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Effects of Different Cooking Methods on Nutritional and Physicochemical Characteristics of Selected Vegetables
Abstract
The objective of the present study was to evaluate the effect of three common cooking practices (i.e., boiling, steaming, and frying) on phytochemical contents (i.e., polyphenols, carotenoids, glucosinolates, and ascorbic acid), total antioxidant capacities (TAC), as measured by three different analytical assays [Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP), ferric reducing antioxidant power (FRAP)] and physicochemical parameters of three vegetables (carrots, courgettes, and broccoli). Water-cooking treatments better preserved the antioxidant compounds, particularly carotenoids, in all vegetables analyzed and ascorbic acid in carrots and courgettes. Steamed vegetables maintained a better texture quality than boiled ones, whereas boiled vegetables showed limited discoloration. Fried vegetables showed the lowest degree of softening, even though antioxidant compounds were less retained. An overall increase of TEAC, FRAP, and TRAP values was observed in all cooked vegetables, probably because of matrix softening and increased extractability of compounds, which could be partially converted into more antioxidant chemical species. Our findings defy the notion that processed vegetables offer lower nutritional quality and also suggest that for each vegetable a cooking method would be preferred to preserve the nutritional and physicochemical qualities.
... However, limited data specifically address the impact of sous-vide cooking on carrot color [20,22,26], total phenolic content [20,22,26], phenolic compound profiles [3], and antioxidant properties [4,20,22,27]. Despite growing interest in the effects of thermal processing on the bioactive compounds in carrots, research on the phenolic compound profile remains scarce and inconclusive, indicating variability in the presence and/or degree of degradation of phenolic acids during processing [4,28,29]. Additionally, studies on the levels of specific bioactive compounds often yield ambiguous conclusions, suggesting either their degradation or release as a result of thermal treatments. For example, Zavadlav et al. [17] demonstrated that phenolic compounds were better preserved in vegetables cooked sousvide than in conventional methods such as boiling or steaming. ...
... Importantly, no studies to date have directly compared the impact of traditional steaming in a steel pot with steaming in a combi oven on the chemical composition of carrot roots. Furthermore, most research has focused on carrot roots that were peeled and cut into cylindrical specimens [4,26,28,29], cubes [21,22], or slices [20,24] prior to processing. This approach may result in different quality attributes compared to those observed in whole carrot roots, which remain underexplored. ...
... µg/g dw), constituting 58.4% of all detected phenolic compounds. Miglio et al. [28] and Ashour and El-Hamzy [29] identified only three phenolic acids in raw carrots: chlorogenic, caffeic, and p-coumaric acids, with chlorogenic acid being the most abundant. Chiavaro et al. [4] reported the presence of five phenolic acids (caffeic, p-coumaric, sinapic, chlorogenic, and ferulic acids) and three flavonoids (quercetin, kaempferol, and luteolin) in raw carrots, with p-coumaric acid as the dominant compound, accounting for 33.7% of the total phenolic content. ...
Carrot (Daucus carota L.) is a globally consumed root vegetable, enjoyed both raw and after thermal processing. This study aimed to evaluate the effect of different heat treatment methods (traditional boiling in water, steaming in a steel pot, steaming in a combi oven, baking in a combi oven, and the sous-vide technique) on carrot color, total phenolic and flavonoid content, phenolic and carotenoid compound profiles, and antioxidant capacity. It was found that heat treatments resulted in significant (p ≤ 0.05) changes in carrot color, with reductions in lightness (L* decreased by 19–24%), redness (a* decreased by 52–67%), and yellowness (b* decreased by 15–25%). Interestingly, processed carrots showed an increase in total phenolics (by 25–133%), total flavonoids (by 60–126%), and total carotenoids levels (by 16–48%) compared to raw carrots. However, specific phenolic and carotenoid compounds showed notable reductions (p ≤ 0.05) after heat treatment, including vanillic acid and rutin (100% reduction after all treatments), α-carotene (up to 33.3% reduction after baking), zeaxanthin (up to 33.3% reduction after baking), and 13-cis-β-carotene (up to 40.7% reduction after steaming in a combi oven). In addition, heat treatment significantly (p ≤ 0.05) increased the antioxidant capacity of carrots, as determined by DPPH and ABTS assays, with increases up to 2.2-fold and 1.6-fold, respectively. The antioxidant properties of processed carrots were strongly correlated (p ≤ 0.05) with total phenolic content and the levels of chlorogenic acid, p-coumaric acid, and β-carotene (r = 0.86–0.96).
... Kido found that heat treatment increased the total phenol content in sweet potato tubers [16]. The possible reason is that heat treatment can soften and break cell components, thus facilitating the release of phenolic compounds [43]. The analysis of uncooked Chinese yams revealed that cooking times of 40, 80, and 120 min had different effects on the TPC and TFC (p < 0.05) ( Table 1). ...
... Compared with the uncooked sample, the IC 50 of pancreatic lipase of AHPs and BBPs with the samples cooked for 40 min decreased, the IC50 of pancreatic lipase of BHPs, AHPs, and ABPs with the samples cooked for 80 min decreased, and the IC50 of pancreatic lipase of BBPs with the samples cooked for 120 min decreased ( Figure 3B). Heat treatment can soften and break cell components, thus facilitating the release of phenolic compounds [43]. The yams released different polyphenols at different cooking times; thus, the pancreatic lipase inhibition was different. ...
... In this study, Ruichang yam polyphenols were extracted from a mixture of solids and liquids after cooking yams, which was different from the previously reported method of cooking yams. However, during the cooking process, the heat could soften and break cell components, facilitating the release of phenolic compounds [43]. Therefore, part of the soluble polyphenols released during the boiling process of the yam remain in the liquid, resulting in an increase in the TPC and TFC after the yam is boiled. ...
In this study, the total polyphenol content (TPC), total flavonoid content (TFC), and biological activity of yam polyphenols (including free phenolics, conjugated phenolics, and bound phenolics) were investigated during home cooking. Polyphenol components were preliminary detected in raw yam by HPLC, including 2, 4-dihydroxybenzoic acid, syringic acid, vanillic acid, 4-coumaric acid, and sinapic acid. TPC and TFC of soluble conjugated polyphenols were the main phenolic compounds in Ruichang yam. Compared with uncooked yam, cooking times of 80 min and 40 min increased the TPC and TFC of multiple types of polyphenols, while cooking reduced the TPC and TFC of AHP (acid-hydrolyzed soluble conjugated polyphenols). All yam polyphenols exhibited good α-Glucosidase inhibitory activity; α-Glucosidase inhibitory activity was significantly higher for a cooking time of 120 min. Only some types of polyphenols had lower pancreatic lipase half-inhibition concentrations than orlistat when cooked. The pancreatic lipase of FPs (free polyphenols), BHPs (alkali-hydrolyzed soluble conjugated polyphenols), and ABPs (acid-hydrolyzed insoluble bound polyphenols) was the stronges when cooking for 80 min, and the pancreatic lipase inhibitory activity of AHPs and BBPs (alkali-hydrolyzed insoluble bound polyphenols) was strongest when cooking for 40 min. Pearson’s correlation coefficient analysis revealed that the TPC was positively correlated with the TFC, the IC50 value of α-Glucosidase was negatively correlated with the IC50 value of pancreatic lipase, and redox activity was positively correlated with the TPC and TFC, respectively.
... This is because consumer acceptance for cooked meat products is determined mainly by the flavour, which is influenced by different cooking methods and storage conditions (Parvin et al., 2020). These methods might also induce a significant changes in their chemical composition (Miglio et al., 2008) which will invariably result in different concentration and bioavailability of bioactive compounds of the product (Miglio et al., 2008) i.e. heating or cooking influences the rate of lipid peroxidation in meat and meat products (Akinwumi and Olagoke, 2019). Thus, the need to evolve food production processes that will provide not only convenience, high organoleptic qualities, health and nutritional benefits, but also shelf stability of the product. ...
... This is because consumer acceptance for cooked meat products is determined mainly by the flavour, which is influenced by different cooking methods and storage conditions (Parvin et al., 2020). These methods might also induce a significant changes in their chemical composition (Miglio et al., 2008) which will invariably result in different concentration and bioavailability of bioactive compounds of the product (Miglio et al., 2008) i.e. heating or cooking influences the rate of lipid peroxidation in meat and meat products (Akinwumi and Olagoke, 2019). Thus, the need to evolve food production processes that will provide not only convenience, high organoleptic qualities, health and nutritional benefits, but also shelf stability of the product. ...
... As shown on There was significant variation in the parameters of total cholesterol and phenols of the nugget samples obtained through different cooking methods. The differences in phenolic concentration in the nugget samples might be attributed to the different degree of heat treatment they were subjected because the types of cooking process can either cause damage to the active constituents or increase the content of bioactive compounds (Miglio et al., 2008;Mena-García et al., 2021). Also, most of the phenolic compounds are relatively unstable when subjected to heat and a significant amount of it is lost during high heat treatment (Abd Ghani et al., 2023). ...
The growing concern over consumption of fatty foods had increased the focus on formulating and developing nutritious and tasty low-fat meat products. However, the cooking methods employed during preparation of a food can change consumer’s perception about the product. Breast and thigh muscles were deboned, grounded, mixed with nugget ingredients to form an emulsion, and then divided into two. Each part was deep-fried or oven-cooked after cutting into nugget pieces (3.5 cm diameter, 1.5 cm thickness, 20.5 g weight). Yield (%), moisture (%), organoleptic characteristics (9 point hedonic scale), cholesterol (%), phenol (mgGAE/100g), were assessed on fresh while Thiobarbituric Acid Reactive Substances (TBARS µg MDA/Kg) and Total Viable Counts (TVC cfu/g) were observed at 0, 7, 14 days of storage. Data were analysed using T-test and factorial analysis @ α = 0.05. Oven cooked nuggets yield (90.43) and moisture (55.84) were significantly higher (Pr t <0.05) than 79.94 (yield) and 52.39 (moisture) deep fried nuggets. No significant differences (Pr t>0.05) in colour, aroma, tenderness and overall acceptability were observed in both nuggets. Flavour (6.00) and juiciness (5.00) of oven-cooked nuggets are significantly higher (Pr t<0.05) than 4.83 (flavour) and 3.17 (juiciness) of deep-fried nuggets. Cholesterol (62.74) and phenol (176.12) contents of deep-fried nuggets were higher (Pr t<0.05) than 55.72 (cholesterol) and 144.53 (phenol) of oven cooked nuggets. Oven-cooked nuggets TBARS (2.44, 2.69, 4.21) were significantly higher (p<0.05) than 2.18, 2.41, 3.96 in deep-fried nuggets at 0, 7 and 14 days respectively. Oven-cooked TVC at 0 (2.50), 7 (4.51) and 14 (5.98) days were significantly higher (p<0.05) than 2.10, 4.09 and 5.62 of deep-fried nuggets at 0, 7 and 14 days respectively. The high yield and organoleptic scores elucidated that oven-cooked nuggets are well accepted and this method can be used in the preparation of chicken nuggets.
... Therefore, changes in the surface reflective properties and the depth of light penetration into the tissues of boiled OFS might be responsible for the rise in greenness, as indicated by the a* value [40]. These alterations are likely caused by the expulsion of air and other dissolved gases from cells and their substitution with cooking water and cell juices, as previously indicated [39,41]. The increase in YI is probably due to the slight increase in pheophytin content. ...
... The current study focused on boiling at a standardized temperature (100 • C) for methodological consistency and comparability. However, considering various cooking methods such as steaming, microwaving, etc. would reflect real-world practices and enhance the practical relevance of the findings [41]. L*, a*, b* represent brightness, redness to greenness, and yellowness to blueness respectively. ...
... Several studies have shown that food processing disrupts cellular structures like lignin and polysaccharides and releases phenolic compounds [48]. As a result, the polyphenolic compounds in vegetables were lost completely in the process of diffusion into the boiling water during cooking [41]. The results of Gorinstein, Leontowicz (2006) [49] also indicated that the total polyphenol content of cooked garlic (100 • C, 40 or 60 min) was lower than that found in fresh garlic. ...
Consuming vegetables is linked to health benefits. Onion flower stalk (OFS) is a green vegetable with a mild onion flavor and is widely consumed in South Asia. The objectives of this study were to evaluate and understand the effect of boiling time (5, 10, 15, and 20 minutes at 100°C) on physicochemical, bioactive compounds, and antioxidant activity of OFS. After boiling, moisture content and pH increased, whereas total soluble solids, water activity, titratable acidity, and ascorbic acid content decreased with increasing boiling time. The ascorbic acid content of fresh OFS was 20.59 mg/100g fresh weight (FW), which decreased by 71.45% after 20 minutes of boiling. The total phenolics, flavonoids, and tannin content in fresh OFS were 517.16 mg GAE/kg FW, 341.55 mg QE/kg FW and 517.28 mg TAE /kg FW, respectively. However, prolonged boiling caused a damaging effect on these bioactive compounds. It was observed that 20 min of boiling caused about 55.50% loss in total phenolic, 58.44% loss in total flavonoids, and 55.88% loss in total tannin. The decrease in antioxidant capability was associated with the depletion of phytochemicals. The results also demonstrated that the ethanolic extract of OFS was effective in DPPH free radical scavenging activity. For extended boiling, the IC50 values rose gradually, indicating a decrease in antioxidant activity. Kinetic modeling showed that a first order model could more accurately anticipate changes in ascorbic acid and bioactive components with a higher R2. Findings from this research would be useful in designing thermal processing equipment for fruits and vegetables.
... The use o the raw leaves is the most common ways to consume basil; however, it is also popular to consume its cooked orm at home and restaurants. Although consumption o resh unprocessed vegetables is widely advocated, evidence is emerging that many natural compounds is increased when vegetables are cooked (Miglio et al., 2008). It has been reported that cooking enhanced the content o bioactive compounds such as phenols, favonoids, and carotenoids, at-soluble vitamins, and antioxidant activities remarkably, while decreased the level o condensed tannin, proximate composition (ash, bre, and protein), water-soluble vitamins, and minerals in vegetables (Thi and Hwang, 2015;Knecht et al., 2015;Lee et al., 2018;Lima et al., 2019;Moorthy et al., 2020;Boua et al., 2020;Neves et al., 2021;Zhou et al., 2022). ...
... Group th was ovenbaked in a conventional oven at 180 • C or 30 min. The last group microwaved at high power (850 W) or 5 min (Miglio et al., 2008;Ateea et al., 2012;Hossain et al., 2017;Mwebi and Ogendi, 2020;Neves et al., 2021). Finally, the samples were reeze-dried (Lyophilizer, CHRiST, Germany). ...
... Green leay vegetables have a high ability to preserve α-tocopherol, which may be due to the increase in the ability to extract this vitamin, ollowed by the denaturation o proteins and the complete decomposition o the plants cell wall, which occurs during cooking. In the present study, the signicant reduction o at-soluble vitamins in the cooking method is attributed to the instability o this group o vitamins at higher temperatures (170 • C) (Miglio et al., 2008). ...
In the present study, the effect of boiling, stir-frying, steaming, oven-baking, and microwaving on vitamins content, proximate composition, minerals content and their bioaccessibility, pigments level, phenolic compounds (rutin, rosmarinic acid, and quercetin), and antioxidant activity of basil (Ocimum basilicum L.) leaves were evaluated. Cooking was reduced the mineral content and the lowest bioaccessibility were interestingly found for heavy minerals. Boiling caused a significant decrease in water-soluble vitamins and minerals content, whereas, stir-frying caused losses the fibre, protein, and carbohydrate content more than the other cooking methods. Furthermore, steaming and microwave methods were able to retain most of the protein, water-soluble vitamins, minerals, phenolic compounds, and antioxidant activity and may thus be selected as suitable methods for cooking basil based foods and recipes.
... Parallel to the results of this study, Miglio et al. (2008) found that the β-CAR content of boiled courgette and broccoli increased significantly after boiling compared to uncooked vegetables (18% for courgette, 15.78% for broccoli), but during frying the β-CAR content was significantly lost (10.41% for zucchini, 64.91% for broccoli). In addition, Granado et al. (1992) found that the β-CAR values in raw and boiled (38 min) red pepper were 414 μg⋅100 g⁻ 1 fw and 683 μg⋅100 g⁻ 1 fw, respectively. ...
... In a study in which dried red peppers were fried, it was reported that DPPH and FRAP values did not show significant changes compared to unfried dried peppers (Loizzo et al., 2013). In another study conducted by Miglio et al. (2008), it was reported that the DPPH and FRAP values of carrots, zucchini and broccoli increased significantly after boiling, steaming and frying processes, while Armesto et al. (2016Armesto et al. ( , 2019 pointed out that the cooking time did not make a significant difference in the DPPH and FRAP values in any of the cooking methods they applied to Galega cabbage. The cooking process may affect the antioxidant capacity of different vegetables. ...
... Similar findings were suggested by Sergio et al. [22] who tested the impact of various cooking methods (e.g., boiling, steaming, and microwaving) on the content of total phenolic compounds of various wild edible greens and reported a negative impact of cooking depending on the method and the species. The same findings were suggested by Miglio et al. [68] for carrots, broccoli florets, and courgettes, although the authors identified a varied impact depending on the species and the individual compound. ...
... Moreover, the decoctions recorded a different profile, with several compounds being identified in amounts between 0.501 and 0.78 mg/g of extract. According to the literature, apart from the cooking method [22,68], agronomic practices may have an impact on the phenolic compound composition of raw leaves of wild edible species [21,45,46]. ...
Wild edible greens are a key ingredient of the so-called Mediterranean diet and they are commonly used in various local dishes in their raw or processed form. Domestic processing of edible greens may affect their nutritional value and chemical profile. In this work, six wild species (e.g., Cichorium spinosum L. (S1); Centaurea raphanina subsp. mixta (DC.) Runemark (S2); Picris echioides (L.) Holub (S3); Urospermum picroides (L.) Scop. ex. F.W. Schmidt (S4); Sonchus oleraceus L. (S5); and S. asper L. (S6)) were assessed for the effect of domestic processing (boiling) on chemical composition and bioactivities. Concerning the chemical composition, glucose, oxalic acid, α-tocopherol, and α-linolenic acid were the most abundant compounds, especially in P. echiodes leaves. After decoction, mainly sugars, tocopherols, and oxalic acid were decreased. The species and processing affected the phenolic compounds content and antioxidant, cytotoxicity, and anti-inflammatory activities. Specific compounds were not previously detected in the studied species, while hydroethanolic extracts contained a higher total phenolic compound content. Hydroethanolic and aqueous extracts were effective towards a range of bacterial and fungi strains. Therefore, the consumption of leaves has health-promoting properties owing to the bioactive compounds and can be integrated into healthy diets. However, domestic cooking may affect the chemical profile and bioactivities of the edible leaves, especially in the case of free sugars and phenolic compound content where a significant reduction was recorded in leaves after decoction. On the other hand, domestic processing could be beneficial since it reduces the oxalic acid content in edible leaves, which is considered an antinutritional factor.
... Ghana Price and Jorgensen (1985); Kpodo et al. (1996) Mawè Muchoki et al. (2011) Igbatim et al. (2014 composition, concentration and bioavailability of nutrients and bioactive compounds (Miglio et al., 2007). During cooking, protein quality is improved due to the inactivation of proteinase inhibitors such as tannins and trypsin inhibitors, as well as, to the heatinduced structural changes that facilitate proteolysis (Liener and Thompson, 1980;Van Der Poel, 1990;Patterson et al., 2016;Drulyte and Orlien, 2019). ...
... Roasting generally imparts desirable sensory qualities, enhances palatability, and reduces antinutritional factors in peanuts (Lund, 1989;Olaoye and Onilude, 2008). Thermal treatments such as boiling, blanching, frying, and steaming have all been reported to increase phenolic content and antioxidant activity of vegetables (Miglio et al., 2007;Mwebi and Ogendi, 2020;Huarte et al., 2021). During the processing of yellow yam (Dioscorea cayenensis), roasting and frying are reported to increase the carbohydrate and gross energy content significantly. ...
... Ghana Price and Jorgensen (1985); Kpodo et al. (1996) Mawè Muchoki et al. (2011) Igbatim et al. (2014 composition, concentration and bioavailability of nutrients and bioactive compounds (Miglio et al., 2007). During cooking, protein quality is improved due to the inactivation of proteinase inhibitors such as tannins and trypsin inhibitors, as well as, to the heatinduced structural changes that facilitate proteolysis (Liener and Thompson, 1980;Van Der Poel, 1990;Patterson et al., 2016;Drulyte and Orlien, 2019). ...
... Roasting generally imparts desirable sensory qualities, enhances palatability, and reduces antinutritional factors in peanuts (Lund, 1989;Olaoye and Onilude, 2008). Thermal treatments such as boiling, blanching, frying, and steaming have all been reported to increase phenolic content and antioxidant activity of vegetables (Miglio et al., 2007;Mwebi and Ogendi, 2020;Huarte et al., 2021). During the processing of yellow yam (Dioscorea cayenensis), roasting and frying are reported to increase the carbohydrate and gross energy content significantly. ...
Foods that are produced and processed locally using some forms of traditional knowledge are important for achieving food and nutrition security in Africa. These food crops are generally nutritious, being rich in essential nutrients and bioactive food compounds necessary for health promotion. Additionally, most African indigenous food crops are better adapted to local growing conditions, fulfil economic needs and are highly resistant to abiotic and climate-induced stresses. Hence, the proper utilisation of locally grown and wild foods crops will help contribute to the improvement of food security, nutrition value, health, and income generation in the African continent. In this review, we focus not only on the determinants of food insecurity in Africa but also discuss the scope, nutrition, and health impact of some common locally grown foods in Africa. We also highlight some traditional processing methods for harnessing the value of these foods, as well as farming and economic/agribusiness practices that can be used to promote the cultivation of foods in an African context. In conclusion, we reiterate that the production and processing of sustainable, locally available foods is essential to providing long-term food security for Africa. There is, therefore, the need for empowerment of local farmers and increased investments in research as well as the formulation of national/regional policies that intend to reduce food insecurity with emphasis on indigenous sustainable food systems for improved access to locally available, nutritious, and healthy foods in Africa.
... Thus, when the mature pods were cooked, they lost color purity, whereas, when tender, their color chrome increased during cooking. This has been related to a modification in the surface-reflecting properties caused by the replacement of intercellular air with cell juice [34]. On the other hand, the hue of the cooked pods increased during the first 5 min of boiling, and then decreased until it remained stable between 12 and 20 min of heat treatment regardless the stage of ripening of the samples. ...
... The retention of antioxidant activity brought about by blanching could be related to the development of enzymatic reactions (PPO) [33]. Furthermore, according to [34] an overall increase of total antioxidant capacities was observed in cooked carrots, courgettes, and broccoli by different methods (boiling, steaming, and frying). This may be because of matrix softening and increased extractability of compounds, which could be partially converted into more antioxidant chemical species. ...
Moringa oleifera is a plant native to India that is well adapted to warm climates with a high yield and low agronomic requirements. Pods are one of the edible parts of this plant and are commonly consumed in some places, (India, Morocco, etc.) when in an early vegetative state. However, both production and consumption of this plant are scarce and seasonal in Europe and treatments to extend its shelf life are required. Therefore, the aim of this study has been to evaluate the variation in the physicochemical properties of Moringa oleifera pods at two stages of maturity, tender and mature, in terms of mass variation, optical and mechanical properties, protein content, total antioxidant capacity and phenolic profile, after boiling them in tap water at 100 °C for different lengths of time (0, 2, 5, 8, 12, 16, and 20 min). The mass of the tender pods increased by 15% during cooking, while the mature pods gradually lost weight. The protein content was approximately 4% with no significant change brought about by cooking. Ferulic, trans-cinnamic, p-coumaric, and ellagic acids were found in the fresh pods. During cooking, these phenols disappeared, and others appeared, including epicatechin and quercetin 3-glucoside, especially in the tender pods. In conclusion, boiling could contribute to an improvement in the organoleptic properties of moringa pods and to an extension of their storage and to wider availability on the market.
... This vitamin is sensitive to heat, light, and oxygen. Cooking methods such as boiling or steaming can lead to significant losses (up to 50-70%), while microwaving or steaming helps retain more nutrients [14]. The recommended dietary allowance (RDA) for vitamin C varies by age, sex, and physiological status, thus for adult males the RDA is 90 mg/day, for adult females the recommended dose is 75 mg/day; smokers need an additional 35 mg/day due to increased oxidative stress [15]. ...
Vitamin C or ascorbic acid is essential for human life and is required for a range of physiological functions in the human body. Ascorbic Acid (AA) is a natural and powerful water-soluble antioxidant. The importance of vitamin C in keeping the human organism in good health has been extensively documented. Human beings cannot produce vitmin C on its own, as it does not possess the required enzymes (L-gulonolactoneoxidase), similar to other primates, guinea pigs, rats and bats. In food analysis, the correct method for the determination of vitamin C should measure the combined content of ascorbic acid and dehydroascorbic acid to determine the total content of vitamin C. There are a large number of methods permitting direct analysis of ascorbic. The purpose of this work paper is to present different titration methods used for determination of vitamin C
... Cooking techniques can enhance food safety and organoleptic properties, while also affecting nutrient concentration and bioavailability in vegetables [8,9]. Traditional methods like stewing and boiling may lead to nutrient loss, mainly of antioxidants and water-soluble vitamins [5,7,[10][11][12]. ...
Background/Objectives: The process of cooking food can result in alterations to its nutrient composition due to changes in water content and the destruction or loss of certain micronutrients that occur in response to heat. This study examined the impact of diverse cooking techniques, namely grilling, microwave, and steam, on the macronutrients and minerals of vegetables commonly utilized in Italian cuisine (two varieties of zucchini, eggplants, and potatoes). Methods: The proximate composition was determined according to the Association of Official Analytical Chemists (AOAC) methods. The content of the minerals (Ca, K, P, Mg, Na, Fe, Zn, and Mn) was determined via ICP plasma after liquid washing. Results: Regarding macronutrients, the results revealed a notable difference in the carbohydrate profiles, whereas mineral retention demonstrated considerable heterogeneity. Some minerals, such as Na, Ca, Mn, and Fe, were found to be more prone to significant increases or losses. Moreover, the true retention factor (TR) calculations indicated that microwave cooking resulted in higher retention compared to the other methods for zucchini, while grilling demonstrated higher TR than microwave cooking for eggplants. Potatoes exhibited lower TR values than the other vegetables and their steaming resulted in higher retention than microwave cooking for K, P, Fe, and Zn. Conclusions: The results confirm the heterogeneous behaviors of minerals in commonly consumed Italian vegetables subjected to different cooking methods. The data underscore the need for additional research to understand the effects of heat treatments on mineral profiles and to determine specific retention factors linked to various cooking techniques. The significant gap between “true” and “apparent” retention factors, caused by changes in water content during cooking, highlight the need for new experimental data to update and enrich the existing literature on this topic.
... Cooking methods have a significant influence on the bioavailability of food nutrients. According to Miglio et al.(2008), cooking induces significant changes in the chemical composition, concentration and bioavailability of nutrients and bioactive compounds in vegetables. The proportion at which nutrients in vegetables are retained after cooking relative to the amount of nutrient present in the raw vegetables before processing is referred to as nutrient retention. ...
Purpose: The objective of this study was to subject African nightshade and vegetable Amaranth to different household cooking methods (boiling, steaming, microwave and stir frying) and test them on the changes of total phenolic content (TPC), antioxidant property (ferric reducing-antioxidant power (FRAP) activity and DPPH radical scavenging activity), macronutrients and micronutrients. Methodology: The African nightshade, (HB) and the Amaranthus leaves, (AL) used in the preparation of all the dishes were purchased from the same farmer at Nkwen in Mezam division of the North West Region of Cameroon. Standard methods were used to determine each analyte at the Laboratory of Food Science and Metabolism (LabSAM) of the University of Yaounde 1 and Nkolbisson Food Technology Laboratory, Yaounde, Cameroon. Findings: The TPC of leafy vegetables ranged from 256.64 to 1184.08 mg GAE/100g, with higher levels observed in cooked forms compared to raw ones. Steaming significantly increased FRAP in both African nightshade and amaranth, followed by microwaving and boiling, with steamed samples showing the highest antioxidant activity. Cooking methods also enhanced DPPH free radical scavenging activity, with microwaved African nightshade (HBM) and steamed amaranth (ALS) exhibiting the highest activity. Nutritional analysis revealed variations in dry matter, ash, protein, crude fiber, and total sugars, with steamed vegetables (ALS, HBM, HBS) generally having higher nutrient levels. Mineral and vitamin analyses showed iron (19.08–34.87 mg/100g DW), zinc (1.06–3.92 mg/100g DW), vitamin C (93.85–231.42 mg/100g DW), and provitamin A (16.5–62.85 mg/100g DW) levels were higher in cooked vegetables compared to their raw counterparts. Unique contribution to theory, practice and policy: This study demonstrates that different cooking techniques impact the nutritional composition and antioxidant activities of the indigenous vegetables; African nightshade and vegetable amaranth. The findings provide valuable insights for optimizing the cooking methods of these vegetables to enhance their health benefits. Thus this study greatly contributes to providing healthy choices on the different ways in which these vegetables can be cooked.
... In a previous study, ho of broccoli increased from 118 to 124 after microwaved for 60 s; and thus color changed from typical green to yellow green. 23 Broccoli blanched with microwave appeared darker than blanched with hot water. In the previous broccoli study of Yuan,24 no cell disruption leading the release of organic acid for the conversion of chlorophyll (green) into pheophytin (grey-green) was found after 5 or 8 min blanching in boiling water. ...
Broccoli provides a good source of many nutrients and bioactive compounds. However, bitterness of broccoli deterred sensory desirability and furthermore impacted its consumption. Cooking and seasoning addition can be used to reduce the bitterness and to increase the preference of vegetables. The objective of this study aims to investigate the effect of blanching and flavor enhancement with various sauces on the bioactive and organoleptic properties. Broccoli was prepared: raw (C), blanched (B), blanched and flavored with Japanese style sauce (F1), with cheese (F2), and with Chinese style sauce (F3). The bioactive compounds (polysaccharide and phenolic compounds), antioxidant properties (DPPH and ABTS scavenging activities), and sensory preference characteristic were evaluated. The results showed blanching and combined with seasonings significantly altered the color parameters (a*, C* and ho) of broccoli. While blanching and sauces additions improved antioxidant contents and capacity as well as all sensory acceptances tested. Compared to the control, blanching and sauces additions increased the contents of phenolic compounds and polysaccharides from 8.3 to 8.4-10.0 and from 78 to 93-106 mg/g dw, respectively. While blanching and sauces increased the scavenging capacity of DPPH and ABTS from 1.29 to 1.43-1.83 and from 3.28 to 4.52-5.27mg Trolox/100g, respectively. Principal component analysis (PCA) analysis further showed blanching and sauces additions were positively correlated with the acceptance of flavor, taste and overall but negatively correlated to color acceptance. In conclusion, blanching or flavorings retained color acceptance (sensory score >5) and enhanced antioxidant capacity and sensory preference.
... In addition, broccoli remained unchanged during the blanching process, regardless of the presence of leaves or stems. Water-cooking methods including boiling, blanching, and steaming does not seem to significantly alter their carotenoid profiles in vegetables (Granado et al., 1992;Miglio et al., 2007). Briefly blanching or boiling vegetables in water is expected to preserve carotenoids, as it does not involve extreme heat or disrupt plant structure. ...
Phytochemicals are micronutrients known for promoting human health. Among them, carotenoids are natural pigments and crucial bioactive compounds due to their outstanding antioxidant properties. In this study, carotenoids from agricultural crops commonly consumed in Korea were analyzed. Carotenoids were extracted from 61 samples, considering factors such as crop type, color, part, and processing method. Identification and quantification of extracted carotenoids were then performed using HPLC–PDA. The results showed that most green and red leafy vegetables were good sources (> 900 μg/100 g DW) of carotenoids. The carotenoid contents were found to vary depending on the crop part. Colored cereals and their processed products exhibited low carotenoid contents (< 10 μg/100 g DW), while white rice, certain wheat products, adlay, and mushrooms contained no detectable carotenoids. Losses of carotenoids were observed in certain crops during cooking and processing. This study provides valuable insights into the carotenoid content of commonly consumed agricultural crops.
... Preserving the nutritional quality of vegetables post-harvest is essential for maintaining their health benefits and consumer appeal. Minimizing exposure to light, heat, and oxygen, as well as implementing techniques such as blanching and freezing, help retain vitamins, minerals, and phytochemicals (Miglio et al., 2008). ...
This book is an essential resource for anyone involved in the agricultural sector, from farmers to food technologists. The book opens with an exploration of the fundamental concepts, challenges, and importance of post-harvest technology, setting the stage for understanding how to maximize the value and shelf life of agricultural produce. It delves into the post-harvest physiology of crops, providing insights into the processes of maturity, ripening, and senescence, which are critical for maintaining quality and nutritional value.
Handling and transport of agricultural produce are covered comprehensively, with a focus on minimizing physical damage and loss. Techniques for crop cleaning and grading are discussed in detail, highlighting their role in enhancing quality and market value. The book also examines various storage systems and facilities, emphasizing the importance of preserving crop quality and safety over time. A dedicated chapter on post-harvest losses identifies their causes and impacts, offering strategic solutions for mitigation. Advanced storage techniques, such as controlled atmosphere storage, are explored to optimize conditions for long-term preservation. The book addresses traditional and modern drying and dehydration techniques, essential for the preservation of agricultural commodities. Cold chain management is another critical area covered, with strategies for maintaining product quality and extending shelf life. Specific chapters focus on the unique challenges and innovations in post-harvest technology for grain and horticultural crops, ensuring a comprehensive understanding of different agricultural contexts.
Innovation is a key theme throughout the book, with discussions on value addition through food processing, highlighting the potential for product development and market diversification. The emergence of new technologies, including automation, robotics, and the Internet of Things (IoT), is examined for their transformative impact on post-harvest handling. The book concludes with crucial insights into packaging and labeling, ensuring marketability and consumer information, and emphasizes the importance of quality control and food safety standards and regulations in post-harvest processes.
... (Widyastuti et al., 2018). Various cooking methods can aff ect the content of active ingredients and nutritional value of the food, as well as the appearance of the food, which can ultimately aff ect the acceptance of the food (Gliszczynska-Swig et al., 2006;Miglio et al., 2008). The variety of food ingredients and menu preparations also aff ects athletes' acceptance and satisfaction with the food served. ...
Providing food for athletes is a special institutional arrangement that caters to athletes' specific needs. Athletes have different nutritional requirements than the non-athlete population, as they need more nutrients to compensate for the energy expended during training, competitions, and recovery after matches. Additionally, athletes must focus on fluid intake and sufficient nutrients to support post-training recovery for optimal performance. Therefore, meeting the needs and satisfaction of athletes becomes a crucial goal for athlete food service. Satisfaction can be assessed based on various indicators such as variety of menu and ingredients, suitable portion size, taste, serving time, packaging, and food handler hygiene. This study aims to assess athletes' satisfaction with the food service in athlete dormitories. The research is an observational survey with a cross-sectional approach involving 159 athletes aged 13-19 years from PPLP West Java, PPLP DIY, PPLP NTB, and SKO Cibubur. Data collection took place in May and July 2022. The research instrument used was a customer satisfaction survey questionnaire with a Likert scale ranging from 1 to 4, where one indicates 'very poor' and four indicates 'excellent.' The analysis technique used Pearson correlation in SPSS 16.0 software. The research showed a relationship between menu variety, ingredient variety, suitable portion size, serving time accuracy, food packaging, serving area, food handler hygiene, food presentation, and food taste with athletes' satisfaction level. Serving time accuracy, food packaging, hygiene, cleanliness of the serving area, food handler hygiene, food appearance, and taste correlate strongly with satisfaction.
... When the ascorbic acid amounts of the cooked potato samples were examined, the vitamin C value of the sample cooked without oil was determined as 13.32 ± 1.85 mg/kg DW in MW cooking and 11.99 ± 0.46 mg/kg DW in SV cooking (Fig. 3) which were lower than fresh sample's vitamin C value. The initial total vitamin C content generally decreased after all cooking methods (Miglio et al. 2008;Somsub et al. 2008). Cooking can cause up to 100% of a vitamin's labile vitamin C content to be lost. ...
This study aimed to determine the effects of different cooking methods (micro-wave and sous-vide cooking) and different oils (olive, garlic, and thyme) on the bioactive compounds and textural properties as well as sensory properties of yellow-fleshed potatoes. Three different cooking times (10, 15, and 20 min) were applied in sous-vide cooking, while three different power applications (300, 450, and 600 W) were applied in microwave cooking. The highest bioactive components (total phenolic content, antioxidant activity) were found to be significant for the samples cooked with thyme oil at 20 min for sous-vide cooking, and cooked with thyme oil at 300 W for microwave cooking. Total phenolic content and antioxidant activity in the sous-vide cooking method at 20 min for the addition of thyme oil increased by 4.04 and 1.90 times, respectively, while in the microwave cooking at 300 W, they increased by 4.63 and 1.30 times, respectively , compared to the sample cooked without oil. In addition, other oils were found to have significant effects in different time and watt applications. While there was no statistical difference between different cooking methods on vitamin C amounts, olive oil application was the oil that increased vitamin C the most. In addition, the results of sensory analysis and texture analysis were found to be compatible with each other; while thyme oil had a positive effect on bioactive components, it showed negative results in sensory analysis and resulted in low scores. This is considered an important study in terms of adding new information to the literature with the results obtained using different cooking techniques and oils on potatoes.
... Cooking, as a form of thermal processing, is often associated with significant losses of polyphenols, primarily because these compounds are water-soluble and can leach into the cooking liquid [46]. In contrast, cooking in oil tends to result in lower polyphenol losses [47]. The volume of the cooking solution also impacts polyphenol retention, with smaller amounts of water reducing the extent of polyphenol leaching [48]. ...
Polyphenols are organic chemical compounds naturally present in plants, renowned for their anti-inflammatory, antioxidant, immunomodulatory, anticancer, and cardiovascular protective properties. Their bioactivity and bioavailability can vary widely depending on the methods of food processing and interactions with the gut microbiome. These factors can induce changes in polyphenols, affecting their ability to achieve their intended health benefits. Thus, it is essential to develop and apply food processing methods that optimize polyphenol content while maintaining their bioactivity and bioavailability. This review aims to explore how various food processing techniques affect the quantity, bioactivity, and bioavailability of polyphenols, as well as their interactions with the gut microbiome, which may ultimately determine their health effects.
... A diferença observada entre os conteúdos de compostos fenólicos reportados para diferentes flores comestíveis pode ser explicada por fatores como grau de maturação, condições de cultivo, método extrator, tamanho da amostra, condições, tempo, forma de armazenamento, seleção de reagentes e presenças de substâncias interferentes (Naczk;Shahidi, 2006). No entanto, está próximo ao avaliado por Miglio et al. (Miglio et al., 2008) para brocólis in natura que verificou um teor de 4,5 mg EAG/ g amostra. azul. ...
O consumo de flores comestíveis vem se expandindo no Brasil devido as suas propriedades funcionais, que atuam na prevenção de doenças causadas pelo estresse oxidativo nos seres humanos. Apesar disso, poucos estudos foram realizados no Brasil acerca da capacidade antioxidante de flores comestíveis. Assim, o objetivo do presente trabalho foi avaliar as características físico-químicas, quantificar as substâncias bioativas e a capacidade antioxidante da flor comestível Clitória ternatea L. azul e dos seus extratos obtidos por duas técnicas de extração assistida (mecânica e por ultrassom). Inicialmente foi feita uma caracterização físico-química da flor, em seguida foram preparados os extratos seguindo um delineamento fatorial 5x2, níveis de solvente (água, etanol 50%, etanol 60%, etanol 70% e etanol 80%) e métodos de extração (ultrassom e agitador magnético), após produção, os extratos foram analisados. A flor apresentou um teor de umidade de (95,9 ± 6,41%); acidez (0,098 ± 0,008 g ácido cítrico/100g amostra), pH (6,17 ± 0,075), sólidos solúveis (5,00 ± 0,001° BRIX), cinzas (0,56 ± 0,01%), vitamina C (7,58 mg de ác. ascórbico/100g amostra) e carotenoides (22,99 mg de β-caroteno/100g amostra). Os melhores resultados para os extratos avaliados apresentaram elevado conteúdo de compostos fenólicos (9,11 mg EAG/g) e capacidade antioxidante por ABTS (34322,94 μmolTE/g) e Frap (538,61) utilizando a água como solvente e a técnica de extração com o ultrassom.
... On the other hand, cooking with oil can enrich the food, depending on the type of oil. Such is the case of olive oil, which has in its composition high levels of healthy fats such as oleic acid, which reduces bad cholesterol and increases its antioxidant capacity due to an improvement in the content of phytochemicals [12,13]. Heat treatment can cause the appearance of different chemical changes in fruits and vegetables, such as the Maillard reaction. ...
Fruits and vegetables are a fundamental part of people’s diets due to their composition of bioactive phytochemical compounds. These act as antioxidants that neutralize free radicals, which are related to various pathologies causing negative effects on the health of the host. Raw materials subjected to heat treatments at different temperatures allow the production of safe and stable foods. However, through a systematic review, the present research focused on determining whether heat treatments exert variations in the antioxidant capacity of fruits and vegetables. The methodology applied in the collected research studies was used to calculate the total antioxidant capacity. It was observed that FRAP, ABTS, ORAC, and DPPH assays were used. Furthermore, the total phenolic content, which is also related to the antioxidant capacity, was calculated and analyzed using the Folin-Ciocalteu method. The results found by several other authors indicate that the majority refers to the thermal treatment that plays a positive role by increasing the antioxidant capacity of fruits and vegetables. This is due to cell breakdown caused by high temperatures. On the other hand, some results of the authors differed from the above, where, they showed that raw materials, when applied to thermal treatments, reduce the antioxidant capacity due to the inactivation effects of oxidative enzymes. Keywords: fruits, vegetables, trials, antioxidants, total phenols, heat treatment. Resumen Las frutas y hortalizas son una parte fundamental en la dieta de las personas, debido a que presentan en su composición compuestos bioactivos fitoquímicos, mismos que actúan como antioxidantes favoreciendo a neutralizar los radicales libres, que se relacionan con diversas patologías ocasionando efectos negativos en la salud del huésped. Las materias primas sometidas a tratamientos térmicos con diferentes temperaturas, permiten la producción de alimentos seguros y estables. Sin embargo, en la presente investigación mediante una revisión sistemática, se fundamentó en determinar si los tratamientos térmicos ejercen variaciones en la capacidad antioxidante de frutas y hortalizas. La metodología aplicada en la recopilada de diferentes investigaciones sirvió para calcular la capacidad antioxidante total, se observó que utilizan ensayos FRAP, ABTS, ORAC, DPPH y para calcular el contenido de fenoles totales que también se relaciona con la capacidad antioxidante lo analizan mediante el método más conocido que es el de Folin-Ciocalteu. Los resultados encontrados por los diferentes autores se pueden conocer que la mayoría refiere a que el tratamiento térmico desempeña acciones positivas al incrementar la capacidad antioxidante de las frutas y hortalizas, esto se debe al rompimiento celular que ocasionan las elevadas temperaturas. Por otro lado, se encontró investigaciones donde autores difieren con lo anterior, siendo así que en sus exploraciones demuestran que las materias primas al ser aplicadas a tratamientos térmicos la capacidad antioxidante se ve reducida por efectos de inactivación de enzimas oxidativas. Palabras Clave: frutas, hortalizas, ensayos, antioxidantes, fenoles totales, tratamiento térmico.
... Cooking methods such as boiling, steaming, and frying can either enhance or degrade the antioxidant levels in food. For instance, steaming vegetables often preserves more antioxidants compared to boiling, which can lead to significant losses of water-soluble antioxidants like Vitamin C [16]. Storage and preservation effects also play a crucial role; prolonged storage can lead to a reduction in antioxidant levels, while certain preservation techniques, such as freezing, may help maintain them. ...
Antioxidants play a pivotal role in protecting the body from oxidative stress and associated diseases. This review
explores various antioxidant-rich foods and their health benefits, focusing on the types of antioxidants present,
including vitamins (Vitamin C and E), polyphenols, flavonoids, and carotenoids. We examine top antioxidant-rich
foods such as berries, green leafy vegetables, nuts, seeds, herbs, and spices, highlighting their nutritional profiles
and health benefits. Mechanisms of antioxidant action, including free radical scavenging, oxidative stress reduction,
and cellular defense enhancement, are discussed. The review also covers the impact of food preparation on
antioxidant levels and the synergistic effects of combining different antioxidant sources. Additionally, dietary
recommendations for maximizing antioxidant intake are provided, along with future research directions and gaps.
The review concludes that incorporating a variety of antioxidant-rich foods into the diet is crucial for maintaining
optimal health and preventing chronic diseases.
... To ensure the safe consumption of edible oils and fats, several best practices should be followed. Opt for baking and roasting instead of frying to reduce the formation of harmful compounds like acrylamides and PAHs, and avoid excessively high cooking temperatures by choosing oils with high smoke points to prevent degradation [34][35][36][37][38][39][40][41][42][43]. Select high-quality oils with a favorable fatty acid profile and avoid partially hydrogenated oils that contain trans fats; instead, choose oils rich in monounsaturated and polyunsaturated fats, such as olive oil, avocado oil, and canola oil. ...
This review delves into the toxicology of edible oils and fats, focusing on their health implications, processing methods, contaminants, and safety practices. It discusses the types of fats, processing techniques, contaminants, health effects, safe consumption practices, current research, and future directions. The review distinguishes between saturated, unsaturated, and trans fats, examines harmful contaminants, and provides guidelines for healthier choices. It also highlights the impact of dietary fat choices on health and identifies potential future research areas such as personalized nutrition and sustainable fat sources. The review aims to provide practical recommendations for improving health and safety.
... Previous studies have shown that some vegetables reduce their phytochemical contents, for example, polyphenols, carotenoids, and ascorbic acid, after cooking compared to raw. 1 Another study revealed that raw vegetables and salad cause an increase in serum levels of vitamins, including vitamin C, vitamin E, folic acid, β-carotene, and lycopene, in their consumers' bodies. 2 Hence, consuming fresh and raw vegetables like ulam can be one of the best choices for a healthy diet, as its nutritional value, including phytochemical contents remains unchanged due to no heat applied. ...
This study aims to isolate and characterise the Pink Pigmented Facultative Methylotrophs (PPFM) bacteria from the leaves of common Malaysian table salad (ulam). The colonies of PPFM bacteria were obtained using selectively modified Pseudomonas agar based on the appearance of the pink pigment colony. The three selected isolates labelled OJ4, OJ154 [Oenanthe javanica (Blume) DC.] and ML8 [from Melicope lunu-ankenda (Gaertn.) T. G. Hartley] were chosen for characterisation. The result showed the PPFM bacteria colonies (log CFU/g) at the leaf surface of C. caudatus are 4.4 ± 0.1, significantly higher than O. javanica, 3.8 ± 0.2, and M. lunu-ankenda, 3.2 ± 0.1. The selected isolates belong to the Gram-negative group, motile with rod shape with size [length (l) × width (w)] in µm unit 4.3 ± 1.1 × 1.6 ± 0.6, 5.4 ± 0.2 × 1.2 ± 0.1, and 3.5 ± 0.7 × 1.0 ± 0.0, respectively. They show positive urease, catalase, and oxidase activities, while none of them can degrade starch, gelatine, or cellulose, as well as glucose fermentation (MR test) and metabolism actions (VP test), producing indole and hydrogen sulphide gaseous. Only isolate OJ154 demonstrates positive casein hydrolysis and nitrate reduction activities, while only isolate ML8 can utilise citrate but not in lipid degradation. Their sequence analysis of the 16S rRNA indicated that OJ4 and ML8 are Methylobacterium radiotolerans with a similarity of 99%, whereas, OJ154 is Methylorubrum salsuginis with a similarity of 99%. To conclude, PPFM bacteria from the leaves of C. caudatus, O. javanica, and M. lunu-ankenda have been isolated and characterised in particular.
... Conversely, baking at 210°C for 20 min resulted in an increase of 300% of 15Z-PT and 240-360% of PF isomers, compared to raw carrot. Likewise, Miglio et al. 29 reported an increase in PT and PF concentrations after three cooking treatments (boiled, steamed and dried), especially in the case of frying. ...
The effect of different cooking methods (boiling, baking, steaming and microwaving) on the colour and texture of carrots, and on carotenoid bioaccessibility, was investigated to identify the more “sustainable cooking” methods.
... It is understood that the thermal approach induces considerable alterations in the chemical composition and the number of bioactive compounds in plant leaves. Therefore, the utilization of heat during the extraction process of the leaves is anticipated to facilitate the degradation of bioactive compounds (Miglio et al., 2008). Herein, we report the green synthesis of SnO2 NPs using an extract of ground C. odorata leaves, whereby the extraction process was conducted with heat-free treatment, and a comparison was made to the boiled extract. ...
In this research, tin(iv) oxide nanoparticles (SnO2 NPs) using leaf extract of Chromolaena Odorata was successfully synthesized. Although the traditional extraction method typically requires heating for collecting the extract, this study performed the extraction utilizing free heat. Subsequently, a comparative analysis was performed with the boiled version to recognize any distinctions in the formation of SnO2 NPs. Leaves of C. odorata contain bioactive compounds, particularly polyphenolic flavonoids, which potentially serve as effective agents in green synthesis, acting as both reducing and capping agents for Sn 4+. The synthesis was conducted at ambient temperature, followed by calcination at 700°C. FESEM images revealed that the morphologies of SnO2 NPs in both samples were uniform and spherical. The presence of O and Sn elements was further confirmed by EDX analysis, with an atomic composition of approximately 76% and 23%, respectively. XRD obtained the most prominent peaks of SnO2 NPs which are (110), (101), and (211) with fair sharpness for both samples with tetragonal structure. Furthermore, the FTIR spectrum affirmed the presence of pertinent functional groups through the vibration and stretching pattern of SnO2 and Sn-OH groups. Based on these findings, the heat-free treatment of C. odorata extract proves to be comparable to the boiled version in mediating biosynthesis. Nevertheless, the preference is towards the traditional process, as the use of heat enhances the extraction process by increasing the abundance of bioactive compounds without undergoing degradation. Additionally, bioactive compounds aid in stabilizing the structure of SnO2 NPs and preventing agglomeration.
... Specifically, there is a quantitative reduction in aldehydes, alcohols, and ketones in raw samples in comparison to cooked samples (except alcohols in sample CK_ST and RAW_ST, which are 9 in both, and ketones in sample CK_LL and RAW_LL, which remain 1), an increase in esters, carboxylic acids (except carboxylic acids in sample CK_CONTROL and RAW_CONTROL, which are 2 in both), and ethers, while alkanes and alkenes remain nearly unchanged. This behavior is primarily due to two factors: cooking processes and variations in specific compounds [44]. ...
Incorporating insect meals into poultry diets has emerged as a sustainable alternative to conventional feed sources, offering nutritional, welfare benefits, and environmental advantages. This study aims to monitor and compare volatile compounds emitted from raw poultry carcasses and subsequently from cooked chicken pieces from animals fed with different diets, including the utilization of insect-based feed ingredients. Alongside the use of traditional analytical techniques, like solid-phase microextraction combined with gas chromatography-mass spectrometry (SPME-GC-MS), to explore the changes in VOC emissions, we investigate the potential of S3+ technology. This small device, which uses an array of six metal oxide semiconductor gas sensors (MOXs), can differentiate poultry products based on their volatile profiles. By testing MOX sensors in this context, we can develop a portable, cheap, rapid, non-invasive, and non-destructive method for assessing food quality and safety. Indeed, understanding changes in volatile compounds is crucial to assessing control measures in poultry production along the entire supply chain, from the field to the fork. Linear discriminant analysis (LDA) was applied using MOX sensor readings as predictor variables and different gas classes as target variables, successfully discriminating the various samples based on their total volatile profiles. By optimizing feed composition and monitoring volatile compounds, poultry producers can enhance both the sustainability and safety of poultry production systems, contributing to a more efficient and environmentally friendly poultry industry.
... In both boiling and frying, broccoli and courgettes lost a significant proportion of their total phenolic content. 36 Proteins can go through significant chemical changes during food preparation and storage that lower their nutritional value. 37 The presence of antinutrients in the food matrix or the formation of antinutrients by heat or alkaline treatment can alter the amino acid bioavailability and protein digestibility of food. ...
Currently, a large number of people favor meals that are rich in nutraceuticals and phytochemical compounds, which help with the treatment or prevention of chronic diseases. Oral bioavailability is a crucial component of phytochemical bioefficiency, and endogenous mechanisms have a significant impact on how well nutraceuticals and phytochemicals are absorbed by the body. In addition to endogenous variables, exogenous factors that impact the bioavailability of bioactives include the food matrix, food processing, and food storage. Different delivery systems have evolved in this regard, and nanoscale delivery tools have also been created. Delivery methods that use nanostructured lipid carriers show benefits such as enhanced loading capacity, solubility, encapsulation effectiveness, storage stability, bioavailability, and half-life. They also provide safe food systems and regulated release. In this review, the outcomes of recent experimental reports are comprehensively reviewed. In addition, the food processing, storage, gut milieu circumstances, the release process from the food and nano delivery systems in the gastrointestinal tract (GIT) milieu, interactions with other GIT constituents, main delivery systems based on nanostructured lipid carriers for their encapsulation and eventually encapsulating technological barriers, food safety concerns, and regulatory issues of nutraceutical and phytochemical compounds are discussed.
... [7,35] The capacity of VGCE to promote cell viability might be regarding flavonoids containing in the water extract that could easily be released by water. [22,36] Recently, it was found that casticin a polymethoxyflavone isolated from V. trifolia could promote T-cell and B-cell proliferation in leukemia mice. [37] ...
... Broccoli contains significant amounts of health-beneficial compounds, which has increased its consumption by people. Minerals are the building blocks of bones, teeth, blood, and muscle cells, and increase the usefulness of vitamins [9][10][11]. Phenolic compounds play a crucial role in exerting a wide variety of biochemical and pharmacological effects [12,13]. ...
In this study, the effect of different cooking techniques on broccoli moisture, total phenolic, total flavonoid, and radical scavenging capacity results, polyphenol contents, and their quantitative values was investigated. The total phenolic quantities of fresh and cooked broccoli samples were assessed to be between 36.32 (conventional boiling) and 423.39 mg GAE/100 g (microwave heating). The radical scavenging activities of the broccoli samples were reported between 2.55 (conventional boiling) and 4.99 mmol/kg (microwave heating). In addition, catechin and rutin quantities of the fresh and cooked broccoli samples were measured to be between 2.24 (conventional boiling) and 54.48 mg/100 g (microwave heating), and between 0.55 (conventional boiling) and 16.33 mg/100 g (microwave heating), respectively. The most abundant elements in fresh and cooked broccoli samples were K, Ca, P, S, and Mg. The results showed some changes depending on cooking techniques compared to the control. The bioactive properties of broccoli samples cooked by means of conventional boiling, boiling in vacuum bag, and high-pressure boiling were established to be lower compared to the fresh sample. Catechin, 3,4-dihydroxybenzoic acid, rutin, and gallic acid were the key phenolic compounds of fresh and cooked broccoli samples. The phenolic components of broccoli were significantly affected by the applied cooking techniques. The highest protein in broccoli samples was determined in the broccoli sample cooked by boiling in a vacuum bag. There were statistically significant changes among the mineral results of broccoli cooked with different cooking methods.
... However, in a study on jujube puree, vanillic and ferulic acid contents decreased after fermentation [62]. This was assumed to occur due to the loss of heat-labile phenolic compounds and the degradation of polyphenols by lactic acid bacteria [62][63][64]. Even so, avenanthramide A, which showed the highest rate of content increase through germination among the three major isoforms of avenanthramides, is expected to withstand fermentation by being heat-stable and pH-stable [65][66][67]. ...
Hyperpigmentation occurs due to irregular secretion of melanin pigment in the skin. This can affect quality of life depending on its severity, so prevention and management are essential. Oats (Avena sativa L.), a grain consumed worldwide, are known to offer improved health benefits upon germination and fermentation. This study is aimed to investigate the protective effects of lactobacilli-fermented sprouted oat extracts on oxidative stress and melanin overproduction in vitro. The anti-melanogenic effect was investigated using melanin content and tyrosinase activity assays in B16F10 cells, as well as a mushroom tyrosinase-based enzyme inhibition assay. The results showed that L. casei-fermented oat extracts were the most effective for reducing melanin formation by reducing the mRNA expression of microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related protein 2 mRNA expression. Furthermore, L. casei fermentation was effective in improving the total phenolic, flavonoid, and avenanthramide A contents of sprouted oat extracts. The results also demonstrated the antioxidant effects of L. casei-fermented sprouted oat extracts in promoting DPPH radical-scavenging activity, superoxide dismutase-like activity, and reduction in reactive oxygen species levels. Overall, the findings indicate that fermented sprouted oat extracts are promising candidates for antioxidant and anti-hyperpigmentation treatments.
... T cells that express cytokine interleukin 17 are also essentially involved with psoriasis (32) , while vitamin B12 in beef has immunomodulatory effects on T lymphocytes and cytokines (33)(34) . Vegetables are rich in vitamins, bers, and other nutrients (35) . Cooked vegetables retain antioxidant compounds, carotene, and ascorbic acid well; therefore, the daily consumption of vitamins and polyphenols-rich cooked vegetables can produce antioxidant effects and may be bene cial to these patients (36) . ...
The WHO recognizes psoriatic arthritis (PsA) as a severe non-communicable disease, with Europe having the highest prevalence worldwide, affecting around 6.4 million people. Though dietary factors are closely associated with psoriasis (PsO) in clinical studies, few researchers have explored this link through Mendelian randomization (MR). This investigation analyzes the causal association between psoriasis and dietary factors. This study used MR analysis with publicly available genome-wide association studies to uncover causal relationships. Causal inference and effect estimates were determined using the inverse variance weighted (IVW) method. Additionally, sensitivity analysis included weighted median and MR-Egger methods, with leave-one-out analysis to ensure reliability. It was found that bread intake was associated with increased psoriasis risk (OR: 1.008; 95% CI: 1.003–1.015; p = 0.004), while beef consumption (OR: 0.989; 95% CI: 0.979–0.999; p = 0.043), cooked vegetables (OR: 0.967; 95% CI: 0.936–0.999; p = 0.046), and pork (OR: 0.985; 95% CI: 0.973–0.997; p = 0.016) were protective against psoriasis. No causal link was observed between other dietary factors and psoriasis. Overall, the study found that bread intake increased psoriasis risk, while beef, cooked vegetables, and pork consumption reduced it. Other diets showed no causal association with psoriasis.
... A notable decrease in the anti-nutrient components including phytate, tannin, total alkaloids and cyanide was observed in Gari produced using both the single starter cultures and the combined starter cultures. Antinutrients are capable of interfering with the assimilation of important food nutrients and minerals during digestion [70], although, some studies have reported the positive attributes of some anti-nutrients [71,72,73]. Reduced antinutrient composition of tannins, polyphenols and phytate was reported in Burukutu (a Nigerian fermented alcoholic beverage) produced using combined starter cultures of L. fermentum I and S. cerevisiae [54]. ...
Aim: Fermentation subject microbial cells to stress, such as, acid stress which can lead to inactivation of cells and consequently death. Microbial cells have developed mechanisms of adapting to these stress conditions. In this study therefore, the physiological and proteomic responses of Lactiplantibacillus plantarumLC03 and Candida glabrataYC02 to acid stress and their influence on substrate fermentation for Gari production has been investigated. Methodology: Using the turbidimetry method and SDS-PAGE; LC-MS/MS, the physiological and proteomic responses of the LAB and yeast to acid stress were assessed. Analysis of the physiocochemical and organoleptic properties of the fermented cassava using the LAB and yeast alone and in combination was conducted by means of standard methods. Results: Lactiplantibacillus plantarumLC03 and Candida glabrataYC02 had growth at pH 1, 2 and pH 3 respectively with an increased protein intensity of Type I glyceraldehyde-3-phosphate dehydrogenase and enolase 2 respectively. The lowest cyanide content (6.49d), highest protein content (0.94c) and improved organoleptic acceptability (7.92a) was observed in Gari produced with the combination of Lactiplantibacillus plantarumLC03 and Candida glabrataYC02 as starters with significant differences in Gari produced with single starters of Lactiplantibacillus plantarumLC03 and Candida glabrataYC02 and control. Conclusion: Increased protein intensity during acid stress conditions enhanced the survival of Lactiplantibacillus plantarumLC03 and Candida glabrataYC02 (starters), thereby, improving the quality (improved sensory properties, nutritional and reduced anti-nutrient contents) of Gari produced.
... Although nutrients in raw vegetables may be lost during preparation and cooking, these processes can also enhance food flavor and remove anti-nutrients such as tannins and phytic acid or reduce their concentrations (Fabbri & Crosby, 2016). The antioxidant capacity of carrot, courgette, and broccoli increases during cooking with methods such as boiling, steaming, and frying (Miglio et al., 2008). The effects of boiling, steaming, microwaving, and vacuum cooking on chicory stem quality have been evaluated (Renna et al., 2014). ...
Chicory (Cichorium intybus L.; witloof) is a crisp bitter leafy vegetable, popularly used in western cuisine in salads and soups (leaves) and as an alternative to coffee (roasted roots). In this study, we explored the effect of heat processing under various temperatures and for different durations on the nutritional composition of chicory leaves using gas chromatography–mass spectrometry (GC/MS) and principal component analysis (PCA). “Vintor” chicory leaves were processed and homogenized to obtain lyophilized samples, and their moisture content and pH were measured. Heat processing was conducted at 4, 30, 60, and 100°C. Metabolites were extracted and analyzed using GC/MS. The results were statistically analyzed using multiple t‐tests and Tukey–Kramer method. A PCA was conducted using standardized data. A lower temperature (≤60°C) positively influenced the concentrations of nutritional components (sugars, free amino acids, and organic acids), branched‐chain amino acids (which reportedly improve exercise performance), and γ‐aminobutyric acid (which exerts antihypertensive effects). Whereas, a higher temperature (100°C) and microwave processing induced the generation of low‐molecular‐weight sugars from polysaccharides and glycosides, decreased free amino acid concentrations, and caused heat‐induced aminocarbonyl reactions. This study provides valuable information for enhancing the flavor profiles and potential health benefits of chicory leaves by identifying the optimal heat processing parameters for preserving the desired nutritional value.
Practical Application
The palatability, nutritional content, and health benefits of chicory have been evaluated based on its inherent constituents, but changes in these parameters during food processing remain unclear. Heating at 30 and 60°C activated secondary metabolism in chicory, increasing the amino acid and organic acid concentrations, whereas heating at 100°C and microwave processing increased the sugar concentrations in chicory. Thus, the nutritional value and potential health benefits of chicory could be enhanced by processing it under controlled temperatures; the findings are valuable for both consumers and food processing industry.
The escalating presence of antibiotic-resistant bacteria (ARB) in food systems presents a pressing challenge, particularly in preventing contamination and ensuring food safety. Traditional sanitation methods, such as cooking and chemical disinfectants, provide effective means to reduce ARB, yet there is a growing need for additional preventive measures directly on food surfaces. This review explores the potential of chitosan–phytochemical composites (CPCs) as surface coatings to prevent the initial contamination of food by ARB, thereby offering a novel complementary approach to conventional food safety practices. Chitosan, combined with active plant-derived metabolites (phytochemicals), forms composites with notable antibacterial and antioxidant properties that enhance its protective effects. We examine CPC synthesis methodologies, including chemical modifications, free radical-induced grafting, and enzyme-mediated techniques, which enhance the stability and activity of CPCs against ARB. Highlighting recent findings on CPCs’ antibacterial efficacy through minimum inhibitory concentrations (MIC) and zones of inhibition, this review underscores its potential to reduce ARB contamination risks on food surfaces, particularly in seafood, meat, and postharvest products. The insights provided here aim to encourage future strategies leveraging CPCs as a preventative surface treatment to mitigate ARB in food production and processing environments.
Brassicaceae encompasses the important genus-Brassica with about 37 species, including major vegetable species, cultivated globally and consumed worldwide as a part of diet, either raw or processed. They are rich in nutritional, antioxidant, and bioactive compounds, and their intake has often been linked to positive health benefits. Glucosinolate, a plant secondary metabolite and its breakdown products commonly found in these vegetable crops, have potential health benefits. The glucosinolate content of cruciferous vegetables is greatly influenced by various pre-harvest factors, such as the stage of the plant at the time of harvest, environmental conditions, and agricultural practices. Once harvested, these vegetable crops are subjected to different processing conditions, such as boiling, blanching, frying, fermentation, etc., affecting their glucosinolate content. This review aims to overview the glucosinolates from Brassica vegetables, their structure, biosynthesis, and the impact of various pre and post-harvesting factors on their content
Background: Cereal grains are rich in carbohydrates and could trigger a hyperglycemic response which is closely linked to blood pressure status. We aim to examine the associations between the consumption of cereals with different cooking methods and hypertension risk. Methods: We conducted a prospective analysis utilizing the nationwide data of 11,080 adult participants who were free of hypertension at baseline. Cereal intake was assessed using 3-day 24 h dietary recalls with a weighing technique. Hypertension incidence was identified in adherence with the Seventh Joint National Commission guidelines during the follow-up. Cox proportional hazards regression models were used to extrapolate hazard ratios associated with hypertension risk. Results: Over an average follow-up span of 7 years (77,560 person-years), we identified 3643 new hypertension cases. The intake of total, fried, and baked cereals was associated with 15%, 20%, and 20% higher risk of hypertension, respectively. Whole grain consumers had an 8% lower risk of hypertension compared with non-consumers, while total refined grain consumers showed no significant association. Replacing one daily serving of fried or baked cereals with an equivalent serving of boiled cereals was related to a 28% or 14% lower risk, respectively. Conclusions: Total, fried, and baked cereal consumption was positively associated with hypertension risk, while consuming whole grains was related to a lower risk. Modifying cooking methods from frying or baking to boiling for cereals may be beneficial to lower risk. The current study underscores the significance of considering both the degree of processing and cooking methods applied to cereals in addressing hypertension prevention and management.
Polyphenols, as subordinate metabolites of plants, have demonstrated significant antibacterial, anti-inflammatory, and antioxidant action in scientific learn. These compounds exert their effects through various mechanisms, containing interference with microbial cell structures, rule of host immune responses, and neutralization of free radicals. This multifaceted activity positions polyphenols as promising candidates for maintaining human health and treating related diseases. Notably, in the context of escalating antibiotic resistance, the antibacterial properties of polyphenols offer innovative avenues for the development of new therapeutic agents. Additionally, their anti-inflammatory and antioxidant effects hold substantial potential for treating inflammatory diseases and mitigating the aging process. This review aims to summarize the latest findings on the biological activities of polyphenols, highlighting their mechanisms of action and potential applications in health and disease management. Furthermore, optimizing polyphenol extraction methods aligns with the goals of sustainable and green processing, reducing environmental impact while enhancing food safety and extending shelf life. Employing advanced analytical techniques, such as spectroscopy and chromatography, can ensure the accurate evaluation of polyphenol content and efficacy. These efforts collectively contribute to the ongoing improvement of food processing practices and product quality, promoting a healthier and more sustainable future in the food industry.
Ülkemizde ağaç bamya olarak bilinen Araujia sericifera Güney Amerika’ya özgü istilacı, yaprak dökmeyen ipeksi bir bitkidir. . Birçok sebze sahip olduğu biyoaktif bileşenleri ile sağlık üzerinde olumlu etkiler göstermektedir. Sebzelerin içermiş olduğu biyoaktif bileşenler pişirilme işlemi sırasında olumsuz etkilenmektedir. Çalışmada farklı pişirme tekniklerinin Araujia sericifera bitkisinin biyoaktif özellikleri üzerine etkisini belirlemek ve çok kriterli karar verme yöntemiyle en iyi biyoaktif özelliğe ve genel kabul edilebilirliğe sahip pişirme yöntemini tespit etmeyi amaçlamıştır. Farklı pişirme yöntemleri uygulanan ağaç bamya örneklerinin toplam fenolik madde miktarları 4,75-15,15 mg GAE/g aralığında değişim gösterirken sotelenmiş örneklerin diğer pişirme yöntemlerine göre daha yüksek fenolik madde içeriğine sahip olduğu tespit edilmiştir. Çok kriterli karar verme teknikleri sonuçlarına göre ağaç bamyayı pişirmek için yapılan soteleme yönteminin biyoaktivite ve genel kabul edilebilirlik açısından en iyi yöntem olduğu belirlenmiştir.
Spine gourd (Momordica dioica.) is very nutritive vegetable available in market for very short period. The selected spine gourd fruits were cut manually with stainless steel knife and 0.5 cm thick slices were prepared. Slices were allowed for pre treatments and blanching was carried out in boiling water for 3 min. The spine gourd slices were dried by vacuum and cabinet drier up to a moisture content of 6%. Among the pre treatment KMS (0.2%) solution for 20 min. and dried in vacuum driver showed batter retention of chlorophyll content (26.75 mg/100g) ascorbic acid (56.55 mg/100g) total phenol (19.28mg/100g) antioxidant (61.05 µmole TE/ gm) and higher rehydration ratio with less moisture content. Among the packaging material of 200g ALPE, HDPE and LDPE, sample packed in 200g ALPE pouches followed by stored at low temperature (7±1) was found best for six month of storage, As it retain higher ascorbic acid, total phenol, total antioxidant and total chlorophyll content, rehydration radio and less moisture during storage.
Alkaloids are considered major secondary plant metabolites and are found mostly in plants. Some alkaloids are used as a spice in foodstuffs such as fenugreek, black pepper, and long pepper. These spices have large quantities of alkaloidal compounds. Trigonelline is a major alkaloidal compound present in fenugreek seeds, and piperine is present in peppers. Black pepper has a long history of usage in traditional medicines all throughout the world as well as food and condiments (Kaltner et al., 2020). In the Piperaceae, or pepper family, there are about 2,000 species in the Piper genus (Durant-Archibold et al., 2018). Only a few spices from the genus Piper include alkaloids, the biggest class of nitrogenous natural chemical substances. The two species that are most well-known are Piper longum and Piper nigrum, also known as pippali and black pepper, respectively. This genus contains piperidine-type alkaloids (Martha Perez Gutierrez et al., 2013). Numerous traditional medical systems, including traditional Chinese medicine, the Indian Ayurvedic system, and folkloric medicines of Latin America and the West Indies, have used plants from the genus Piper as a cure (Zaveri et al., 2010). Another alkaloid-containing species we have included in this chapter is a short-living and annual medicinal herb Trigonella foenum-graecum belonging to the Fabaceae family. Its major alkaloids are Trigonelline and 4-hydroxy-isoleucine (Nagulapalli Venkata et al., 2017).
This chapter provides an overview of food spices containing alkaloids as major chemical compounds. The major focus is on the sources, traditional uses, and phyto-pharmacological properties of food spices containing alkaloids.
Epidemiological and observational studies and research on the impact of diet on health have contributed to increasing demand for foods that have high nutritional value or that are specific to certain target groups of consumers. The study aims to review information regarding the stability of phytochemical compounds in food matrices subjected to heat treatment. Research on the relationship between the nutritional quality of the diet and the values of inflammatory biomarkers measured in chronic non-transmissible diseases has highlighted the protective role of phytochemical compounds that are naturally present in foods. The development of functional foods based on phytochemical compounds must be supported by understanding the mechanisms of action of phytochemicals, strategies to ensure the maximization of their bioaccessibility and bioavailability, and the establishment of the reference dietary intake. Most studies have focused on quantifying the phytochemical response to processing and identifying the main factors of phytochemical compound stability, for example: type of process, food matrix structure and environment, and storage conditions. The development of functional foods based on phytochemical compounds requires a detailed understanding of the stability of these compounds and the uptake of phytochemicals transported by the food matrix. The strategies for maximizing the bioavailability of phytochemical compounds require in vivo evaluation of the mechanisms of action observed within in vitro studies and establishing reference dietary intake limits by identifying and assessing biological responses.
The effect of water- and steam-cooking on the content of vitamin C, polyphenols, carotenoids, tocopherols and glucosinolates, as well as on the antioxidant activity of broccoli, are reported. Flavonoids, phenolic acids, vitamins C and E, beta-carotene, lutein, and glucosinolates in domestically processed broccoli were quantified using high-performance liquid chromatography (HPLC) methods; total polyphenols were determined with Folin-Ciocalteu reagent. The antioxidant capacities of broccoli extracts were evaluated using the Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The results indicated that steam-cooking of broccoli results in an increase in polyphenols, as well as the main glucosinolates and their total content as compared with fresh broccoli, whereas cooking in water has the opposite effect. Steam-cooking of broccoli has no influence on vitamin C, whereas cooking in water significantly lowers its content. Both, water- and steam-cooking of broccoli results in an increase in beta-carotene, lutein, and alpha- and gamma-tocopherols as compared with fresh broccoli. Similar effects of steaming and water-cooking of broccoli on their antioxidant activity were observed.
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Some of the most exciting research in the last decade has been the discovery of a group of nutrients which have protective effects against cell oxidation. These naturally occurring compounds impart bright colour to fruits and vegetables and act as antioxidants in the body by scavenging harmful free radicals, which are implicated in most degenerative diseases. Epidemiological studies have established a positive correlation between the intake of fruits and vegetables and prevention of diseases like atherosclerosis, cancer, diabetes, arthritis and also ageing. So pronounced has been their effect on ageing that they have been called 'fountains of youth'. Fruits and vegetables have thus had conferred on them the status of 'functional foods', capable of promoting good health and preventing or alleviating diseases. Phenolic flavonoids, lycopene, carotenoids and glucosinolates are among the most thoroughly studied antioxidants. The present review highlights the potential of fruits and vegetables rich in antioxidants, their health benefits and the effect of processing on the bioavailability of these nutrients. The paper also reviews some of the important methods used to determine the antioxidant activity.
Isomerization of carotenoids, which is often encountered in food processing under the influence of temperature and light, may play a role in the observed protective effects of this group of secondary plant products. Investigation of in vitro antioxidant activity of prominent carotenoid geometrical isomers was undertaken in light of recent reports illustrating a large percentage of carotenoid (Z)-isomers in biological fluids and tissues. alpha-Carotene, beta-carotene, lycopene, and zeaxanthin were isolated from foods or supplements and subsequently photoisomerized with iodine as a catalyst. Major Z-isomers of each carotenoid were fractionated by semipreparative C-30 HPLC. In vitro antioxidant activity of all isomers collected was measured photometrically using the Trolox equivalent antioxidant capacity (TEAC) assay. TEAC values of 17 geometrical isomers investigated ranged from 0.5 to 3.1 mmol/L. Three unidentified (Z)-isomers of lycopene showed the highest antioxidant activity, being significantly higher than the result for (all-E)-lycopene, which had approximately two times the activity of (all-E)-beta-carotene. On the other hand, (92)-zeaxanthin had a more than 80% lower TEAC value compared to that of (all-E)-lycopene. These results allow for the in vivo relevance of (Z)-isomers of carotenoids to be considered.
The objective of this work was to study the influence of different methods of food preparation routinely used by catering and food services (in large quantities) on the stability of α-carotene, β-carotene and total carotenoids in carrots. Also, the values of vitamin A were evaluated. The methods of preparation studied were: raw shredded, steam cooking, water cooking with pressure, water cooking without pressure and moist/dry cooking. The quantification of α and β-carotenes was carried out by high-performance liquid chromatography (HPLC), using a reverse phase column (RP-18) with methanol: acetonitrile: ethyl acetate (80:10:10) as the mobile phase and a UV-Visible detector. Total carotenoids were quantified spectrophotometrically at 449 nm. The results showed a retention ranging from 56.0 to 89.1% for the carotenoids, with the moist/dry cooking causing the greatest losses in α and β-carotene. Considering the type of utensils used, the time and temperature, it was concluded that water cooking without pressure was best for reducing losses of carotenoids in carrots prepared by food service. Despite considerable losses in vitamin A value, carrots subjected to routine preparation methods by catering and food services remain a rich source of provitamin A. The methodology developed in this study is now being applied to carotenoid analysis in other vegetables prepared in large quantities.
The ascorbic acid (or vitamin C) content of the fruits and vegetables grown in the district of Trabzon (Turkey) was determined by UV−vis spectrophotometry. Fe, Cu, and Zn contents of the same materials were measured by atomic absorption spectrophotometry, and a comparison was made between the values of local and imported produce. Keywords: l-Ascorbic acid; iron; copper; zinc; determination; dry-ashing; atomic absorption; spectrophotometry; vegetable; fruit
Quantitative estimates of conjugated flavonoid content were obtained by using HPLC to analyze the level of free flavonoids present in acid-hydrolyzed extracts from commercial fruits and vegetables. Cherry tomatoes contained 17−203 μg of quercetin g-1 fresh weight compared to 2.2−11 μg g-1 detected in normal-sized Scottish, Spanish, and Dutch beef tomatoes. The quercetin levels in onions ranged from 185 to 634 μg of quercetin g-1 fresh weight. “Round” lettuce contained 11 μg of quercetin g-1 fresh weight compared to 911 μg g-1 in the outer leaves and 450 mg g-1 in the inner leaves of “Lollo Rosso” lettuce. The conjugated flavonoid content of celery was very variable, ranging from undetectable to 40 μg of luteolin and 191 μg of apigenin g-1 fresh weight. Cooking lowered the quercetin content of both tomatoes and onions with greater reductions being detected following microwaving and boiling than after frying. Keywords: HPLC; quantitative analysis; flavonoids; tomatoes; onions; lettuce; celery; diet
Enzymatic and nonenzymatic browning reactions of amino acids and proteins with carbohydrates, oxidized lipids, and oxidized phenols cause deterioration of food during storage and processing. The loss in nutritional quality and potentially in safety is attributed to destruction of essential amino acids, decrease in digestibility, inhibition of proteolytic and glycolytic enzymes, interaction with metal ions, and formation of antinutritional and toxic compounds. Studies in this area include influence of damage to essential amino acids on nutrition and food safety, nutritional damage as a function of processing conditions, and simultaneous formation of deleterious and beneficial compounds. These compounds include kidney-damaging Maillard reaction products, mutagens, carcinogens, antimutagens, antioxidants, antibiotics, and antiallergens. This overview covers the formation, nutrition, and safety of glycated proteins, characterized browning products, and heterocyclic amines. Possible approaches to inhibiting browning reactions and preventing adverse effects of browning during food processing and food consumption, including protection against adverse effects of heterocyclic amines by N-acetylcysteine, caffeine, chlorophyll, conjugated linoleic acid, lignin, and tea extracts, are also described. This research subject covers a complex relationship of the chemistry, biology, and pathology of browning products and the impact on human nutrition and health. Future study should differentiate antinutritional and toxicological relationships, define individual and combined potencies of browning products, and develop means to prevent the formation and to minimize the adverse manifestations of the most antinutritional and toxic compounds. Such studies should lead to better and safer foods and improved human health. Keywords: Browning prevention; food browning; food safety; glycated proteins; glycosylation; heterocyclic amines; human health; Maillard products; nutrition
The effects of various processing methods on carotenoid, color, and vitamin A content changes in carrot juice were studied. Results showed that canning (121 degrees C, 30 min) resulted in the highest destruction of carotenoids, followed by HTST heating at 120 degrees C for 30 s, 110 degrees C for 30 s, acidification plus 105 degrees C heating for 25 s, and acidification. 13-cis-beta-Carotene was formed in largest amount during heating, followed by 13-cis-lutein and 15-cis-alpha-carotene. The formation of 13,15-di-cis-beta-carotene during canning was due mainly to conversion of 13-cis-beta-carotene, Carrot juice color turned from orange to yellow with intensive treatment. The vitamin A content decreased along with increasing temperature and heating time.
Effects of processing variables on color, α- and β-carotenes, and non-starchy polysaccharides (NSP) of carrot juice products were investigated. Unblanched‘carrots produced the highest amounts of juice and lowest amounts of pulp. Compared to color of fresh juice, canned juice from acetic acid-blanched carrots retained redness best, and juice from unblanched carrots retained the least. Juice products from unblanched carrots retained highest total carotenes. Retorting, concentrating, and freeze-drying partly reduced juice product carotenes. In most cases, the reduced amounts from various processing methods were greater for β-carotene than for α-carotene. NSP contents of juice products ranged from 1.1 to 1.5%.
Summary A continuous vegetable cooker was evaluated and shown to produce improved quality-cooked vegetables under more hygienic conditions as compared to batch type conventional cooking. The operating parameters for 85 ± 3% degree of cooking as optimal were determined for green peas, carrot, kohlrabi, and radish. The final product was evaluated in comparison to conventional cooking in terms of the degree of cooking and product quality (retention of chlorophyll, vitamin C and carotenoids; microbial analysis). The thermal efficiency of the cooker and specific energy consumption were compared with published data for steam blanchers.
Broccoli (cv. Empress) obtained from a local supplier was blanched within 15 h of harvest. It was blanched by four methods in covered containers: conventional boiling water (1900 mL, 4 min) (BW), steam (300 mL water, 4 min) (ST), microwave heated in 1 L glass containers (60 ml water, 4 min, 700 W) (MW), and microwave heated in 1 L Seal-a-MealTM bags (45 ml water, 4 min) (MWB). Aliquots were frozen at -18C for 4 weeks. Fresh unblanched broccoli peroxidase activity ranged from 389 to 829 units/min; activity was essentially zero immediately after all blanching treatments. The highest reduced ascorbic acid (RAA) content occurred in fresh unblanched broccoli. Some peroxidase regeneration occurred during frozen storage. Immediately after blanching, all blanched broccoli had lower RAA content than control broccoli. MW-blanched broccoli retained the greatest amount of RAA and had appearance, visual color, texture scores, and chroma of florets and stems equivalent to ST-blanched broccoli. MW-blanched broccoli had flavor and general acceptability scores similar to BW-blanched broccoli. After 4 weeks in frozen storage, MW-blanched broccoli had the highest RAA content.
Glucosinolates, phenolic compounds and vitamin C were evaluated in two commercial and 12 experimental cultivars of broccoli ( Brassica oleracea L var italica ) grown under uniform cultural conditions. The predominant glucosinolates in all broccoli cultivars were 4‐methylsulphinylbutyl glucosinolate (glucoraphanin) and 3‐indolylmethyl glucosinolate (glucobrassicin). Other glucosinolates such as 4‐OH‐glucobrassicin and N ‐methoxyglucobrassicin were detected in lower amounts. The total glucosinolate concentration ranged from 3.0 µmol g ⁻¹ dw (dry weight) in Pentathlon (experimental cultivar) to 28.3 µmol g ⁻¹ dw in I‐9905 (experimental cultivar). Flavonoids, caffeic acid derivatives and sinapic acid derivatives were quantified in methanol extracts. The largest content of flavonoids was found in the commercial cultivars Marathon and Lord, around 60 mg kg ⁻¹ fw (fresh weight). The vitamin C content of broccoli ranged from 43.1 mg per 100 g fw in Lord (commercial cultivar) to 146.3 mg per 100 g fw in SG‐4515 (experimental cultivar).
© 2002 Society of Chemical Industry
Our objective was to develop a reduced-fat deep-fried carrot chip. Moisture contents of the carrot slices were altered, and fat uptake and quality parameters were measured. Decreasing moisture content of carrot slices significantly decreased (P < 0.05) the yield, hue∘ value, and fat uptake, and increased the redness value, which correlated with increased carotenoid content, but did not influence chip lightness, yellowness, water activity, and moisture content. Removing 50% of the initial moisture content of the carrot slices decreased the chips' fat content from 57% to 38.5%. Adjusting the moisture level of the carrot slices appears to influence fat uptake and carotene content of deep-fried carrot chips.
The effect of microwave and conventional cooking methods on chlorophyll pigments and colour properties of squash, green beans, peas, leek, broccoli and spinach were studied, by HPLC and colorimetry, respectively. In five of six vegetables, chlorophyll a was found more heat resistant compared with chlorophyll b, except in peas. Chlorophylls in peas were retained to the 80–90%, the highest in all vegetables evaluated. Chlorophylls were retained to 19–100%, depending on the vegetable type and cooking method. Pheophytins increased in all vegetables after cooking. Highest chlorophyll a and chlorophyll b losses were observed in boiled leek while microwaved peas and boiled peas retained the most chlorophyll a and chlorophyll b, respectively. Pheophytin a and pheophytin b formation was highest at boiled squash and boiled green beans, which were fifty-ninefold and twenty-onefold compared with fresh ones, respectively. Most of the pheophytin formations occurred in boiled and the least in microwaved vegetables. Surface colour changed depending on the type of vegetable and cooking method.
Public awareness of the purported health benefits of dietary antioxidants has increased the demand for fruit and vegetable products with recognized and improved antioxidant quality and has created new opportunities for the horticulture and food industry to improve fruit and vegetable quality by enhancing antioxidant content. This review describes the production and processing factors that influence the content of the major fruit and vegetable antioxidants, namely vitamin C, carotenoids, and phenolics. There is substantial genetic variation in the content of each of these antioxidant types among fruit and vegetable cultivars. Compared with vitamin C and carotenoids, the levels of phenolic antioxidants appear to be more sensitive to environmental conditions both before and after harvest. Although vitamin C can be readily lost during fresh storage, the content of certain carotenoids and phenolics can actually increase during suitable conditions of fresh storage. Vitamin C and phenolics are more susceptible to loss during processing, especially by leaching from plant tissues into processing water. The combination of cultivar variation and responsiveness to specific environmental conditions can create opportunities for the production and processing of fruits and vegetables with improved antioxidant properties.
Total aliphatic and indole/aromatic glucosinolates and vitamin C content (ascorbic+dehydroascorbic acid) were evaluated in the edible portions of fresh harvested broccoli (Brassica oleracea L. var. italica) florets (Marathon cv.) before and after cooking and in the cooking water. High pressure boiling, steam cooking, microwaving and low pressure boiling (conventional) were the four domestic cooking processes used in this work. Results showed great differences among the four cooking processes and their influence on the content of glucosinolates and vitamin C. Thus, clear disadvantages were detected when cooking in a microwave due to the high loss of vitamin C (40%) and total glucosinolates (74%) in comparison with the rest of treatments. High pressure and conventional boiling had a significant loss rate of total glucosinolates (33% and 55% respectively) regarding fresh raw broccoli, due to the leaching into the cooking water. On the other hand, steaming had minimal effects on glucosinolates and vitamin C. Therefore, we can conclude that a large quantity of glucosinolates and vitamin C will be consumed in steamed broccoli when compared to the other cooking processes.
This study further examines the factors which affect the chromatographic response of carotenoids and contribute to analytical variation and inaccuracies in their quantitative determination. A method for the analysis of carotenoids in vegetables and fruits is described and data are presented for the carotenoid content of vegetables and fruits commonly consumed in the UK. The addition of a solvent modifier (triethylamine) to the mobile phase was shown to improve the recovery of carotenoids from the column from around 60% to over 90%. The linearity and reproducibility of the chromatographic response was investigated and the robustness and reproducibility of the method was measured using a reference vegetable material developed in the laboratory. Short and longer term reproducibility showed an average CV of around 8% for all carotenoids. Analysis showed that good sources (>1000 μg/100 g) of lutein were broccoli, butterhead lettuce, parsley, peas, peppers, spinach and watercress; of lycopene: tomatoes and tomato products; and of β-carotene: broccoli, carrots, greens, butterhead lettuce, mixed vegetables, parsley, spinach and watercress. There was little or no loss of carotenoids on cooking, green vegetables showed an average increase in lutein levels of 24% and in β-carotene levels of 38%. This study and previous studies in our laboratory have demonstrated that a number of factors affect the validity of the ‘peak response’ and are likely to contribute to within and between laboratory variation. It is suggested that the development and use of standard reference materials would significantly improve the quality of data.
The thermal stability of lycopene was evaluated in a carrot cultivar with a high lycopene content (Daucus carota var. Nutri Red) by (a) exposure of carrot homogenates (with/without the addition of oil) to temperatures ranging from 25 to 140 °C; (b) applying convection and microwave vacuum drying to carrot slices. Heating carrot homogenates at temperatures above 100 °C initiated isomerisation of all-trans-lycopene under non-oxidising conditions, as indicated by a significant increase in 9-cis-lycopene. Isomerisation was enhanced at short treatment times, when sunflower oil was added prior to thermal treatment. Independent from an oil supplement, all-trans-lycopene was degraded at temperatures above 70 °C. The ratio of all-trans- to total-cis-isomers changed from 90:10 to 40:60, indicating a higher lycopene bioavailability due to generated cis-isomers. In oil containing carrot homogenates antioxidant properties of the methanol-soluble components raised after heat treatment at 130 °C for 0.5 h. Lycopene remained stable in dried carrots.
Nutritional factors are widely considered to be critical for human health. Overwhelming evidence from epidemiological studies indicate that diets rich in fruit and vegetables are associated with a lower risk of several degenerative diseases. These results have created a new perspective concerning the potential of diet in preventing serious diseases in the future. However, the health-promoting capacity of fruit and vegetables strictly depends on their processing history. This aspect has been generally neglected or scarcely considered in present nutritional and epidemiological studies. Processing is expected to affect content, activity and bioavailability of bioactive compounds.The aim of this article, therefore, is to review the effects of processing on the antioxidant properties of foods by means of a multidisciplinary approach. It is believed that the implications of this challenging and rapidly advancing area may contribute to enhanced industrial competitiveness as well as consumer health and well-being.
The green colour of vegetables changes considerably during heat treatments like blanching. Green beans from two different countries and growing seasons, and the stems and florets of broccoli were heat-treated from 40 up to 96°C. The colour was monitored with the CIE-Lab system. Expressing the green colour as −a*/b* proved to considerably reduce the observed variance within measuring samples. It can be considered as a kind of internal standardisation. The colour was modelled by a simplified kinetic mechanism of two consecutive reactions: one that increases colour, one that degrades colour. First, all data sets were analysed separately using non-linear regression. The obtained percentage variance accounted for (R2adj) ranged from 75.7 to 90.8%. Allowing separate initial conditions but with the kinetic parameters in common, the data of the same vegetable type (green beans and broccoli separately) could be pooled and analysed together (R2adj=87.4 and 77.2%, respectively). The kinetic parameters obtained were so similar that a complete pooled and generic analysis was possible even for green beans and broccoli together. These findings greatly validate the developed model and indicate that the formation and degradation of visible colour in vegetables is governed by processes related to the colouring compounds (like chlorophyll and chlorophilides), irrespective of the vegetables under study.
The Total Radical-Trapping Antioxidant Parameter (TRAP) of 10 freshly prepared human plasmas was measured by a new fluorometric assay. In this method, the rate of peroxidation induced by 2,2′-diazobis (2-amidinopropane) dihydrochloride (ABAP) was monitored through the loss of fluorescence of the protein R-Phycoerythrin (R-PE). The lag-phase induced by plasma was compared to that induced by 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox, a water-soluble analogue of vitamin E). Proteins (but not their sulphydryl groups) interfere with the analysis, partially protecting R-PE when all plasma antioxidants are exhausted. A Trolox-induced lag-phase must therefore be measured on each plasma sample. We found that ascorbate (2.5–5.3%), α-tocopherol (2.9–8.5%), urate (19.6–61.0%), and thiol groups (17.3–42.3%) jointly explain up to 70% of TRAP. Thus, either other compounds present in plasma are likely to exert antioxidant action, or a marked synergistic action between antioxidants should be postulated to exist. This latter hypothesis is supported by the finding that the simultaneous inactivation of ascorbate and thiol groups produces a loss in antioxidant capacity of plasma greater (26%) than the sum of the decreases produced by the separate inactivation of each of the two compounds. The proposed method appears simple, reliable, and allows the rapid handling of a reasonable number of freshly prepared plasma samples. Given the rapid loss of TRAP upon storage, the latter characteristic is crucial in studies on humans, involving a large number of subjects.
Dietary antioxidants, such as water-soluble vitamin C and phenolic compounds, as well as lipid-soluble vitamin E and carotenoids, present in vegetables contribute both to the first and second defense lines against oxidative stress. As a result, they protect cells against oxidative damage, and may therefore prevent chronic diseases, such as cancer, cardiovascular disease, and diabetes. Brassica vegetables, which include different genus of cabbage, broccoli, cauliflower, Brussels sprouts, and kale, are consumed all over the world. This review focuses on the content, composition, and antioxidant capacity both lipid- and water-soluble antioxidants in raw Brassica vegetables. The effects of post-harvest storage, industrial processing, and different cooking methods on stability of bioactive components and antioxidant activity also are discussed.
Texture is a major quality attribute of plant-based foods. The plant cell wall is a key determinant of texture in fruit and vegetables; its properties influence the way in which plant tissues undergo mechanical deformation and failure during mastication. Processes such as cooking, and physiological events such as ripening can reduce the strength of cell adhesion in many vegetables and fruit through depolymerization of pectic polysaccharides. There is considerable interest in reducing such cell separation to prevent over-softening, loss of juiciness and development of mealiness. Recent research on Chinese water chestnut has implicated diferulic acid cell-wall crosslinks in the thermal stability of cell adhesion and, therefore, maintenance of crispness after cooking. In this review, we discuss the potential for exploiting this finding in other edible plant organs, and assess the likely effects that enhanced crosslinking might have on other quality attributes.
Vitamin C, including ascorbic acid and dehydroascorbic acid, is one of the most important nutritional quality factors in many horticultural crops and has many biological activities in the human body. The content of vitamin C in fruits and vegetables can be influenced by various factors such as genotypic differences, preharvest climatic conditions and cultural practices, maturity and harvesting methods, and postharvest handling procedures. The higher the intensity of light during the growing season, the greater is vitamin C content in plant tissues. Nitrogen fertilizers at high rates tend to decrease the vitamin C content in many fruits and vegetables. Vitamin C content of many crops can be increased with less frequent irrigation. Temperature management after harvest is the most important factor to maintain vitamin C of fruits and vegetables; losses are accelerated at higher temperatures and with longer storage durations. However, some chilling sensitive crops show more losses in vitamin C at lower temperatures. Conditions favorable to water loss after harvest result in a rapid loss of vitamin C especially in leafy vegetables. The retention of vitamin C is lowered by bruising, and other mechanical injuries, and by excessive trimming. Irradiation at low doses (1 kGy or lower) has no significant effects on vitamin C content of fruits and vegetables. The loss of vitamin C after harvest can be reduced by storing fruits and vegetables in reduced O2 and/or up to 10% CO2 atmospheres; higher CO2 levels can accelerate vitamin C loss. Vitamin C of produce is also subject to degradation during processing and cooking. Electromagnetic energy seems to have advantages over conventional heating by reduction of process times, energy, and water usage. Blanching reduces the vitamin C content during processing, but limits further decreases during the frozen-storage of horticultural products.
The bioavailability of all-trans-β-carotene from vegetables depends among other things on the molecular linkage and the food matrix in which it is incorporated. It is assumed that cooking can increase the bioavailability by disruption of the plant cell wall and releasing from protein complexes. But it can also lead to isomerization and degradation of all-trans-β-carotene. In this investigation the influence of different domestic cooking methods on the all-trans- and cis-β-carotene as well as the α-tocopherol content in fresh and frozen broccoli and red sweet pepper is examined. While in fresh broccoli all cooking methods lead to a significant release of all-trans-β-carotene and α-tocopherol in the frozen broccoli no change or a decrement occurs. In the fresh and frozen peppers no change or a significant loss of α-tocopherol and all-trans-β-carotene is observed. A slight increase in the cis-isomers of β-carotene can only be found by cooking fresh broccoli.
Glucosinolates in different ecotypes of Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort. widely distributed in Southern Italy and locally known as “friariello” and “cima di rapa”, were characterized and their glucosinolate composition was compared with that of broccoli (Brassica oleracea L. var. italica).Although these two vegetables have a similar morphologic aspect, they showed a very different glucosinolate profile. While glucoraphanin, glucobrassicin and 1-methoxyindol-3-ylmethyl were confirmed as the main compounds in broccoli, gluconapin and glucobrassicanapin were identified for the first time as the molecular markers of friarielli and other Brassica rapa plants. Broccoli can by grouped according to their glucosinolates concentration by PCA analysis.
A method for measuring the antioxidant capacity and/or the amount of a specific antioxidant in a sample, which comprises: a) at least two samples (A) and (B) to be assayed in parallel; b) addition of an antioxidant deactivator to sample (A) which selectively deactivates the antioxidant ability of an antioxidant in the sample; c) addition of a redox indicator to both samples (A) and (B), the indicator being capable of indicating the antioxidant capacity of each sample absorbance of electromagnetic radiation; d) measurement of the change in absorbance of electromagnetic radiation of the indicator in each sample at a given time interval, from the time when the redox indicator was added to or mixed with the samples or immediately prior to this addition or mixing until a given time after the redox indicator was added; e) determining the antioxidant capacity of the sample and/or the specific antioxidant in the sample, by relating the change in absorbance of electromagnetic radiation of step (d) to the absorbance value of a standard solution run under the same conditions or to molar absorptivity value. US6177260; US6177260 B1; US6177260B1; US6,177,260; US 6,177,260 B1; 6177260; Application No. 08/893,519
A liquid chromatographic method has been described for the determination of total vitamin C, ascorbic acid (AA) and dehydroascorbic acid (DHAA) in fruits and vegetables. The complete separation of AA and DHAA could be achieved on a C18 column using 0.2 M KH2PO4 (pH adjusted to 2.4 with H3PO4) as the mobile phase at a flow-rate of 0.5 ml/min. Since the detection sensitivity was poor for DHAA even at 210 nm, it was estimated as the difference between the total AA after DHAA reduction and AA content of the original sample, using dithiothreitol (DTT) as the precolumn reductant. The reaction times for the complete conversion of DHAA to AA at room temperatures were 150, 120, 90 and 75 min for 1, 2, 4 and 8 mmol DTT per mmol of DHAA, respectively. The percentage recovery ranged from 81.7 to 105.9. AA contents of some selected fruits and vegetables were analyzed comparatively by liquid chromatography and enzymatic assay to validate the method.
The phytonutrient intake associated with tomato consumption depends also on cultivar and fruit ripening stage. This work associates the antioxidative ability, the level of carotenoids, and the amount of glycoalkaloids to the main carpometric characteristics of four different typologies of tomatoes: "cherry", "cluster", "elongated," and "salad". These typologies have different weights and shapes, and they are usually consumed in the Mediterranean area at different ripening stages. Results showed that the considered tomato typologies also differ in their antioxidative ability and their carotenoid and glycoalkaloid contents. Growing conditions are also important in determining fruit characteristics: the analysis of the same cultivar of cherry tomato produced under the influence of moderate salt stress showed increases in the lipophilic antioxidative ability and the amount of carotenoid, whereas the level of glycoalkaloid decreased.
Methods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H- and 13C-NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included.
Isomerization of carotenoids, which is often encountered in food processing under the influence of temperature and light, may play a role in the observed protective effects of this group of secondary plant products. Investigation of in vitro antioxidant activity of prominent carotenoid geometrical isomers was undertaken in light of recent reports illustrating a large percentage of carotenoid (Z)-isomers in biological fluids and tissues. Alpha-carotene, beta-carotene, lycopene, and zeaxanthin were isolated from foods or supplements and subsequently photoisomerized with iodine as a catalyst. Major Z-isomers of each carotenoid were fractionated by semipreparative C(30) HPLC. In vitro antioxidant activity of all isomers collected was measured photometrically using the Trolox equivalent antioxidant capacity (TEAC) assay. TEAC values of 17 geometrical isomers investigated ranged from 0.5 to 3.1 mmol/L. Three unidentified (Z)-isomers of lycopene showed the highest antioxidant activity, being significantly higher than the result for (all-E)-lycopene, which had approximately two times the activity of (all-E)-beta-carotene. On the other hand, (9Z)-zeaxanthin had a more than 80% lower TEAC value compared to that of (all-E)-lycopene. These results allow for the in vivo relevance of (Z)-isomers of carotenoids to be considered.
A total of 927 freeze-dried vegetable samples, including 111 white cabbages, 59 carrots, 51 snap beans, 57 cauliflower, 33 white onions, 48 purple onions, 130 broccoli, 169 tomatoes, 25 beets, 88 peas, 88 spinach, 18 red peppers, and 50 green peppers, were analyzed using the oxygen radical absorption capacity (ORAC) and ferric reducing antioxidant capacity (FRAP) methods. The data show that the ORAC and FRAP values of vegetable are not only dependent on species, but also highly dependent on geographical origin and harvest time. The two antioxidant assay methods, ORAC and FRAP, also give different antioxidant activity trends. The discrepancy is extensively discussed based on the chemistry principles upon which these methods are built, and it is concluded that the ORAC method is chemically more relevant to chain-breaking antioxidants activity, while the FRAP has some drawbacks such as interference, reaction kinetics, and quantitation methods. On the basis of the ORAC results, green pepper, spinach, purple onion, broccoli, beet, and cauliflower are the leading sources of antioxidant activities against the peroxyl radicals.
The 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS(*)(+)) assay was adapted to a flow injection (FI) system to obtain a sensitive and rapid technique for the monitoring of antioxidant activity of pure compounds and complex matrixes, such as beverages and food extracts. The FI system includes a HPLC pump that flows the mobile phase (a solution of ABTS(*)(+) in ethanol) through a 20 microL loop injector, a single bead string reactor filled with acid-washed silanized beads, a delay coil and a photodiode array UV-visible detector. The technique was very sensitive, with limits of detection and of quantification of 4.14 and 9.29 micromol of Trolox/L, respectively, and demonstrated high repeatability and reproducibility. The proposed technique was then applied to the evaluation of the antioxidant activity of some pure compounds, demonstrating good agreement with published data obtained by the original spectrophotometric ABTS(*)(+) assay. Finally, the total antioxidant activity of 10 beverages was determined by both the proposed and the original method. The values ranged from 0.09 mmol L(-)(1) for cola to 49.24 mmol L(-)(1) for espresso coffee and did not result significantly different from those obtained by the original spectrophotometric ABTS(*)(+) assay (Student's paired t-test: t = 1.4074, p = 0.1929). In conclusion, the proposed FI technique seems suitable for the direct, rapid and reliable monitoring of total antioxidant activity of pure compounds and beverages and, due to the ability to operate in continuous, it allows the analysis of about 30 samples h(-)(1) making the assay particularly suitable for large screening of total antioxidant activity in food samples.
Epidemiologic studies have demonstrated an inverse association between consumption of fruits and vegetables and morbidity and mortality from degenerative diseases. The antioxidant content of fruits and vegetables may contribute to the protection they offer from disease. Because plant foods contain many different classes and types of antioxidants, knowledge of their total antioxidant capacity (TAC), which is the cumulative capacity of food components to scavenge free radicals, would be useful for epidemiologic purposes. To accomplish this, a variety of foods commonly consumed in Italy, including 34 vegetables, 30 fruits, 34 beverages and 6 vegetable oils, were analyzed using three different assays, i.e., Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP) and ferric reducing-antioxidant power (FRAP). These assays, based on different chemical mechanisms, were selected to take into account the wide variety and range of action of antioxidant compounds present in actual foods. Among vegetables, spinach had the highest antioxidant capacity in the TEAC and FRAP assays followed by peppers, whereas asparagus had the greatest antioxidant capacity in the TRAP assay. Among fruits, the highest antioxidant activities were found in berries (i.e., blackberry, redcurrant and raspberry) regardless of the assay used. Among beverages, coffee had the greatest TAC, regardless of the method of preparation or analysis, followed by citrus juices, which exhibited the highest value among soft beverages. Finally, of the oils, soybean oil had the highest antioxidant capacity, followed by extra virgin olive oil, whereas peanut oil was less effective. Such data, coupled with an appropriate questionnaire to estimate antioxidant intake, will allow the investigation of the relation between dietary antioxidants and oxidative stress-induced diseases.
It has been shown that thermal processing of tomatoes and sweet corn results in increased antioxidant activities despite the loss of vitamin C. Until now, it is unclear whether this positive effect of thermal processing occurs with all crop produce. Therefore, analysis of a root vegetable (beets) and of a legume (green beans) was undertaken to address this question. Antioxidant activity of beets processed under typical commercial processing conditions remained constant despite an 8% loss of vitamin C, a 60% loss of color, and 30% loss of dietary folate. There was a slight but significant 5% increase in phenolic content of processed beets. In contrast, vitamin C and dietary folate content of green beans remained constant, whereas a 32% reduction in phenolic compounds occurred after typical commercial processing conditions. The antioxidant activity of green beans was reduced by 20%. These findings along with previous works suggest that the effects of thermal processing vary with the respective produce crop type. It also reinforces the concept that optimal health benefits may be achieved when a wide variety of plant foods (fruits, vegetables and whole grains) and preparation methods are incorporated into the diet.
Glucosinolates (GLSs) are relatively inert (Z)-N-hydroximinosulfate esters, possessing a sulfur-linked beta-D-glucopyranose moiety and a variable side chain, found almost exclusively in cruciferous vegetables. Following cell disruption, they are hydrolysed by plant myrosinases, forming a group of chemically reactive and biologically active compounds. There is considerable evidence that these breakdown products, when consumed in the diet, may affect the risk of developing chronic diseases. However, in order for any compound to exert an activity in vivo, it is necessary to reach the site of action in an appropriate form and sufficient concentration. Deleterious and toxic effects may be observed at high concentrations: hence, bioavailability is a key factor defining the physiological, beneficial dose window of GLS hydrolysis products (GLS-HPs). For some GLS-HPs, this window can be rather narrow, and therefore is a critical parameter to be considered. In this review we critically evaluate the present state of knowledge on all factors that affect bioavailability of GLS-HPs. This includes liberation from the plant material, absorption from the digestive system, distribution around the body, metabolism and excretion.
This review of the medical literature from 1994 to 2003 summarizes the relationship between raw and cooked vegetables and cancer risk and examines whether they may affect cancer risk differently. Twenty-eight studies examined the relationship between raw and cooked vegetables and risk for various cancers. Twenty-one studies assessed raw, but not cooked, vegetables and cancer risk. The majority of these assessed risk of oral, pharyngeal, laryngeal, esophageal, lung, gastric, and colorectal cancers. Most showed that vegetables, raw or cooked, were inversely related to these cancers. However, more consistent results were found for oral, pharyngeal, laryngeal, esophageal, and gastric cancers. Nine of the 11 studies of raw and cooked vegetables showed statistically significant inverse relationships of these cancers with raw vegetables, but only 4 with cooked vegetables. The few studies of breast, lung, and colorectal cancers also suggested an inverse relationship with both raw and cooked vegetables, but these results were less consistent. In the two studies of prostate cancer, there was no association with either raw or cooked vegetables. One of two bladder cancer studies found an inverse relationship with cooked, but not raw, vegetables. Possible mechanisms by which cooking affects the relationship between vegetables and cancer risk include changes in availability of some nutrients, destruction of digestive enzymes, and alteration of the structure and digestibility of food. Both raw and cooked vegetable consumption are inversely related to epithelial cancers, particularly those of the upper gastrointestinal tract, and possibly breast cancer; however, these relationships may be stronger for raw vegetables than cooked vegetables.
The influence of thermal treatment and light exposure on degradation and isomerization of the predominant carotenoids (lutein and beta-carotene) occurring in green leafy vegetables was assessed. The effect of lipid addition on carotenoid stability was also evaluated. For the first time, the stabilities of pure carotenoids and chloroplast-bound carotenoids were compared. Besides degradation, heating caused carotenoid isomerization in all samples. Whereas pure carotenoids favor 13-cis isomers, in native chloroplasts and heated chloroplasts 9-cis isomers were predominant. Illumination of freshly prepared chloroplast isolates caused an initial increase in the level of lutein (9.6%) and beta-carotene (29.8%), while pure carotenoids exhibited time-dependent degradation. The addition of lipids to chloroplast preparations had the reverse effects on the retention of both carotenoids after heating; isomerization was not significantly affected. It was demonstrated that carotenoid stability has to be evaluated for every individual pigment in its genuine environment. Stability data based on model systems (e.g., pure carotenoids) may not be transferred to complex food matrices without intensive investigation.
Glucosinolates profile of Brassica rapa L. subsp SylVestris L. Janch. var. esculenta Hort. Food Chem19) Dürust, N.; Sumengen, D.; Durust, Y. Ascorbic acid and element contents of foods of Trabzon Turkey
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Separation, identification, and quantification of carotenoids in fruits, vegetables and human plasma by high performance liquid chromatography
- F. Khachik
- G. R. Beecher
- M. B. Goli
- Khachik F.