Article

Bioactive substance contents and antioxidant capacity of raw and blanched vegetables

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Five commonly consumed vegetables in Malaysia namely, four-angled bean (Psophocarpus tetragonolobus D.C.), French bean (Phaseolus vulgaris L.), long bean (Vigna sesquipedalis L.), snow pea (Pisum sativum var. macrocarpon L.) and snap pea (Pisum sativum) were blanched in boiling water for 10 min. The contents of total phenolics, ascorbic acid and β-carotene, and the antioxidant capacity as typified by β-carotene and free radical scavenging activity (DPPH) assays were determined for the raw and blanched vegetables. The study revealed that blanching caused a significant (p < 0.05) increase in β-carotene content [fresh (389–539 µg/100 g), blanched (510–818 µg/100 g)], except in snow pea. Conversely, there was a significant (p < 0.05) decrease in ascorbic acid content [fresh (1.2–7.8 mg/100 g), blanched (0.67–3.8 mg/100 g)]. After blanching, the total phenolic content and antioxidant activity either decreased or increased depending on the type of vegetables. The total phenolic content was positively correlated with the antioxidant activity of the studied vegetables to some extent, but not with ascorbic acid or β-carotene.Industrial relevanceBeans (four-angled bean, French bean and long bean), and peas (snow and snap pea) are commonly consumed vegetables in Malaysia. However, the scientific information regarding blanching and its effect on the total phenolic content and antioxidant activities is very limited. This work showed that blanching caused an increase in the carotene, total phenolic content and antioxidant activities in some of the selected vegetables. This work is important since, consumption of raw vegetables does not have high nutritional qualities and antioxidant activities as shown in this work.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... To have a better insight on the effect of blanching on PS and the oil extraction mechanism, microscopic studies were done on both unblanched and blanched pomegranate seeds using a scanning electron microscope (SEM). The SEM images in Figure 1 confirm that blanching disintegrated the PS cell walls, loosening the hemi-cellulose, cellulose and pectin networks of PS [36,39]. Compared with unblanched PS, the SEM graph from blanched PS exhibited clear pores on the cells walls ( Figure 1A,B). ...
... Further, increasing the blanching time to 5 min at a constant blanching temperature of 90 • C significantly increased the TPC by 1.5 mg GAE/g PSO (Table 2). In the seed cells, the phenolic compounds are bonded to other compounds to form complex structures [36]. Blanching PS could have reduced the complexation of phenolic compounds with the polysaccharides, proteins and pectin, thereby increasing their mass transfer into the oil phase. ...
... Blanching PS could have reduced the complexation of phenolic compounds with the polysaccharides, proteins and pectin, thereby increasing their mass transfer into the oil phase. In addition, blanching PS could have initiated polymerization and increased the phenolic compounds [36]. Apart from enhancing the cell wall permeability, blanching may cause significant degradation or leaching of the phenolic compounds, a phenomenon that may explain the significant decrease in TPC (3.41-2.01 ...
Article
Full-text available
This study investigated the effect of blanching pomegranate seeds (PS) on oil yield, refractive index (RI), yellowness index (YI), conjugated dienes (K232), conjugated trienes (K270), total carotenoid content (TCC), total phenolic compounds (TPC) and DPPH radical scavenging of the extracted oil. Furthermore, phytosterol and fatty acid compositions of the oil extracted under optimum blanching conditions were compared with those from the oil extracted from unblanched PS. Three different blanching temperature levels (80, 90, and 100 • C) were studied at a constant blanching time of 3 min. The blanching time was then increased to 5 min at the established optimum blanching temperature (90 • C). Blanching PS increased oil yield, K232, K270, stigmasterol, punicic acid, TPC and DPPH radical scavenging, whereas YI, β-sitosterol, palmitic acid and linoleic acid were decreased. The RI, TCC, brassicasterol, stearic acid, oleic acid and arachidic acid of the extracted oil were not significantly (p > 0.05) affected by blanching. Blanching PS at 90 • C for 3 to 5 min was associated with oil yield, TPC and DPPH. Blanching PS at 90 • C for 3 to 5 min will not only increase oil yield but could also improve functional properties such as antioxidant activity, which are desirable in the cosmetic, pharmaceutical, nutraceutical and food industries.
... IFPs from each cultivar presented a different behaviour after blanching; while the TPC of those from Medjool fruits (M1, M2 and M3) were not affected (p > 0.05) or reduced by 32% in M4 (p < 0.05), C4 increased its content by 67% (p < 0.05). Both behaviours were detected also by Wen, Prasad, Yang, and Ismail (2010) in vegetables, and these authors summarised different hypothesis: (i) as a possible breakdown of tannins during heating process, what favours their extractability; (ii) as a disruption of the cell membranes by the thermal processing; thus, phenolics in plants that are usually bonded to dietary fibre, proteins or sugars in complex structures become more available; (iii) and as possible formation of phenolic compounds at high temperature due to a higher availability of precursors. It may be also suggested that Confitera dates could have a higher content of polyphenoloxidase (PPO), or diverse type of phenolics with different affinity as a substrate for the enzyme than Medjool dates. ...
... This may suggest that in Confitera dates would be necessary the blanching process to maintain a higher level of phenols in the IFP. In contrary, Wen et al. (2010) also mentioned that some studies found phenolic compounds to be sensitive to heat, and blanching could cause a significant loss of TPC, which can leach into the boiling water, as occurred in Medjool fruits. ...
... This also mirrors that in general IFPs from unripe dates are richer in tannins. Some IFPs (M3B and C4B) had major tannin content when coming from unblanched dates, what could be explained by the inactivation of the PPO after blanching, or by the reasons previously commented for the TPC (Wen et al., 2010). Nevertheless, the rest of IFPs presented a smaller or the same value when dates were submitted to the blanching treatment, as occurred for the TPC. ...
... Blanching, as a vegetable processing method, involves the heating of the vegetables to a temperature sufficiently high to destroy the enzymes present in the tissue. It is a popular method of processing vegetables, including A. digitata leaves, that is intended to terminate the action of enzyme, shorten the drying and dehydration time, and set the color of the vegetables (Wen et al. 2010). However, how it impacts the phenolics composition, antioxidant activity, and inhibitory effect of A. digitata leaves extract on some enzymes associated with T2D has not been reported. ...
... Although blanching is intended to terminate the action of enzyme, shorten the drying and dehydration time, and set the color of vegetables (Wen et al. 2010), studies have shown that it influences the functional attributes of several plant products including the polyphenol content of Coriandrum sativum leaves and fruits (Kaiser et al. 2013); the total phenolics content and antioxidant activity of turnip greens (Martínez et al. 2013); the color, texture, polyphenols, and antioxidant capacity of Irish York cabbage (Jaiswal et al. 2012); and the inhibitory ability of Amaranthus cruentus extract on αamylase and αglucosidase activities (Oboh et al. 2013). Hence, the influence of blanching on the phenolics composition, antioxidant activity, and inhibitory effects of A. digitata leaves extract on the activities of αamylase, αglucosidase, and aldose reductase was evaluated in this study. ...
... Against the losses recorded for all other phenolics, the level of quercetin increased by 45.4% after blanching. This exclusive increase may be attributed to enhanced extractability (Wen et al. 2010), following the disruption of the cell wall of the leaves, as well as the hydrolysis of quercitrin. The extracts scavenged DPPH* and ABTS* + , and reduced Fe 3+ to Fe 2+ (Table 2), and these represent their antioxidant activity. ...
Article
Full-text available
Adansonia digitata (A. digitata) leaves serve as food and have several medicinal uses in many parts of the world. This study evaluated the influence of blanching on the phenolics composition, antioxidant activity, and inhibitory effect of methanol extract of A. digitata leaves on the activities of some key enzymes (α‐amylase, α‐glucosidase, and aldose reductase) implicated in type 2 diabetes (T2D) in vitro. Reverse‐phase HPLC analysis revealed that the leaves had appreciable levels of flavonoids and phenolic acids, including catechin, epicatechin, rutin, quercitrin, quercetin, kaempferol, and luteolin (flavonoids); gallic, chlorogenic, caffeic, and ellagic acids (phenolic acids). Blanching caused significant (P < 0.05) decrease in the flavonoids and phenolic acids contents; DPPH* (2,2 diphenyl‐1‐picrylhydrazyl radical) and ABTS*⁺ [2,2‐azinobis (3‐ethyl‐benzothiazoline‐6‐sulfonic acid) radical cation] scavenging ability; reducing power; and Fe²⁺‐induced lipid peroxidation inhibitory capacity of the extract. Similarly, the inhibitory effect of the extract on the activities of α‐amylase, α‐glucosidase, and aldose reductase was significantly (P < 0.05) reduced due to blanching. Thus, A. digitata leaves extract could be effective for the management of T2D due to its flavonoids and phenolic acids content, antioxidant properties, and inhibitory potency on the activities of α‐amylase, α‐glucosidase, and aldose reductase. However, blanching militated against the levels of these functional attributes of the leaves and, therefore, may not be recommended for their optimal retention.
... Therefore, the slightly increase in the content of βcarotene could be due by a better release of the food matrix. These findings are in agreement with those found by Wen et al. (2010) who revealed an increase in βcarotene content in different plant tissues such as Fourangled bean, long bean, French bean, snow pea, and snap pea by blanching treatment. In addition, it has been observed that the growing area could affect the content of phytochemicals among cultivars (Kevers et al., 2007; Lu et al., 2009). ...
... L2 had about 20% higher DPPH @BULLET radical scavenging activity for blanched and for fresh mangoes. The DPPH @BULLET method has been recently used by Jaiswal et al. (2012) and Wen et al., (2010), they observed that antioxidant capacity measured as radical scavenging activity was lower compared with nontreated produce. In contrast, Vina et al. (2007) found an increase in radical scavenging activity in Brussels sprouts after blanching treatment which is in agreement with our results. ...
Article
Mangoes are an important worldwide tropical fruit and are best noted for their color, juicy texture, and sweet flavor, along with important phytochemical constituents. Phenolic compounds influence the organoleptic quality of fruits and provide health benefits thanks to their antioxidant capacity. Mango cultivars differ in their content of antioxidant components due preharvest factors including climatic conditions, agricultural practices, and geographical localization. However, food composition databases never take into consideration the fact that concentrations of nutrients and their activity may change through cooking practices such as blanching. The aim of this research was to investigate the influence of blanching and the geographical growing area on physiological and antioxidant parameters of 'Tommy atkins' mango fruits. They were harvested at the physiologically ripe stage in two regions. Two groups were established: blanching treatment and control fresh fruits. Chemical properties and antioxidant evaluations were determined. The blanching treatment showed positive effect on fruit from both regions increasing the antioxidant constituents. Also, the geographical origin presented influence on the antioxidant parameters. We concluded that hot treatment like blanching is a recommended practice to increase the antioxidant status of mango fresh produces. Therefore, 'Tommy' mango should be considered a good source of these compounds providing important health benefits.
... and 29.35 mg/100g for papaya pulp, pumpkin and sweet potato, respectively, as reported by Luximon-Ramma et al. (2003), El-Fiky et al. (2007). Total carotenoids and total phenolic compound were increased after blanched process for pumpkin and sweet potato these results are agreement with those reported by Hart and Scott (1995) and Wen et al. (2010). Organoleptic evaluation of mango pulp and its blends: Data in Table 3 revealed that the mango pulp (T) as well as those blended with papaya pulp, pumpkin puree and sweet potato puree had the highest scores of color, taste, odor, appearance and overall acceptability. ...
... respectively. While, radical activities scavenging (RAS%) for blanched pumpkin and blanched sweet potato increased from 33.47 to 41.88% and from 31.03 to 46.46 %, respectively, these results are in agreement with those obtained by (Wen et al., 2010) who has reported a blanching caused an increase in the carotene, total phenolic content and antioxidant activities. Also, Rossi et al. (2003) reported that blanching of fruit greatly increased the radical-scavenging activity of the juice. ...
Conference Paper
Full-text available
Continuous biological H2 production from pre-treated rice straw waste using a mesophilic up- flow anaerobic staged reactor (UASR) at different organic loading rates (OLRs) was investigated. OLR was varied from 7.1 to 26 g COD/l. d. A steady improvement in H2 yield (HY) was recorded from 7.1 g COD/l. d. (95.5 mmol/d.) up to 21.4 g COD/l. d. (117 mmol/d.), and showed a decreasing trend of 107.1 mmol/d. at OLR of 26 g COD/l. d. Likely, H2 production (HP) revealed a gradual improvement in concurrence with OLR from 7.1 to 21 g COD/l.d and decreased thereafter. Carbohydrate degradation and COD conversion efficiency vary also with an increase in OLR. When the OLR was from 7.1 to 21.4 g COD/l.d., the COD and carbohydrate removal was over 70 and 80 %. At higher OLR of 26 g COD/l.d., the COD conversion and carbohydrate degradation efficiency was declined.
... Ranganathan et al. Further, the presence of other antioxidants like carotenoids, phenolics, enhancers, etc., in the premix may also protect the L from oxidation that could have been another reason for the higher levels of L bioavailability compared to the purified L (Wen, Prasad, Yang, & Ismail, 2010). Hence, preprocessing of food is one of the critical factors in determining the bioavailability of L from foods. ...
... Hence, preprocessing of food is one of the critical factors in determining the bioavailability of L from foods. Wen et al. (2010) have shown that the blanching caused a greater increase in β-carotene content (31.1%) than the fresh except in snow pea. Maiani et al. (2009), Valduga et al. (2009 and Mamatha, Arunkumar, & Baskaran (2012) have reported that thermal processing enhances the extractability and bioavailability of carotenoids by disrupting food matrices. ...
Article
Full-text available
ABSTRACT Health food (ready-mix) was prepared from maize and vegetables a source of lutein (L) and zeaxanthin (Z) and studied for its quality characteristics (moisture sorption isotherm, sensory, microbiological, chemical composition, and storage stability) on storage at varying temperatures for 3 months and L+Z bioavailability in mice. Results revealed a decrease in the L+Z level (4.70, 9.24, and 13.85%) of ready-mix stored at 4, 27, and 37°C, respectively. Critical relative humidity and critical moisture content of the product was 64% and 12.24%, respectively. The product is well accepted and was not affected adversely during storage. L+Z bioavailability from ready-mix in mice was higher in plasma (29.4%), liver (58.7%), and eye (14.6%) than control (mice received diet with purified L). To conclude, L+Z in the ready-mix is stable and more bioavailable than control. These findings may help in understanding the importance of simple food processing to improve L bioavailability under its deficient condition among an elderly population.
... Isabelle et al. (2010) reported that the TPC of French bean, cowpea, snap pea and snowpea were 30, 129, 41, and 141 mg GAE.100 g −1 , respectively, which was higher than in this study. Wen et al. (2010) reported that the TPC of winged bean, French bean, cowpea, snow pea, and snap pea were 63. 73, 49.73, 93.28, 114.60, and 127.05 mg GAE.100 g −1 , respectively. ...
... Kevers et al. (2007) reported that antioxidant activity (DPPH) of French bean was 0.68 µmol TE•g −1 that is comparable to the present results. Wen et al. (2010) reported that the DPPH radical scavenging potential of cowpea, snow pea and snap pea was higher than winged bean and French bean. It is difficult to compare the result of those studies with this study since results were reported as percent inhibition of radical DPPH, not as Trolox equivalents. ...
Article
Full-text available
Underutilized, or lesser-known legumes, adapted to local conditions, could be a good source of nutrients, but have not received sufficient examination. Of particular interest is amounts of antioxidants in underutilized legumes. The underutilized legumes winged bean [Psophocarpus tetragonolobus (L.)], sword bean [Canavalia gladiata (Jacq.) DC.], jack bean [C. ensiformis (L.) DC.], scarlet bean (Phaseolus coccineus L.), and velvet bean [Mucuna pruriens (L.) DC], were evaluated for phenolics content and antioxidant potential. For comparison, the commercially cultivated legumes vegetable such as French bean (Phaseolus vulgaris L.), green and purple, cowpea [Vigna unguiculate (L.) Walp.], garden pea (Pisum sativum L.), edible-podded pea (Pisum sativum var. macrocarpon L.), and fenugreek (Trigonella foenum-graecum L.) were also evaluated for phenolics content and antioxidant potential. Antioxidant activity was measured using the in vitro assays: ferric reducing antioxidant power (FRAP), cupric reducing antioxidant power (CUPRAC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and Trolox equivalent antioxidant capacity assays (TEAC). Total phenols and total flavonoids varied from 18.38 to 595.50 mg/100 g fresh weight (fw) and 4.24–154.58 mg/100 g fw, respectively. Velvet bean seed and pods were the richest sources of phenolic antioxidants with very strong potential. A high, positive, correlation exists between phenolics and antioxidant potentials indicating phenolics are the principal natural antioxidants present in the legumes. Agglomerative hierarchical clustering was used to understand possible classification of legume vegetables based on their bioactive antioxidant compounds and antioxidant potential. The distance between velvet bean seed and pods was less pronounced than the distance between them and the other samples indicating they have greater antioxidant potential than the other legumes. Use of velvet bean in the diet could increase intake of health-promoting compounds.
... However, published data on the contents of phenolic acids are limited for fresh beans, such as kidney bean (Phaseolus vulgaris L.), cow pea (Vigna unguiculata), and hyacinth bean (Lablab purpureus). Most of the literature focused on the determination of total polyphenols by Folin-Ciocalteu colorimetry in these above vegetables [22]. Additionally, daylily (Hemerocallis fulva L.) and soybean sprouts, as traditional Chinese food, are consumed widely and deeply loved by people for their high nutrition value. ...
... Meanwhile, p-coumaric acid was detected in minute amounts in snow pea (0.09-0.22 mg/kg fresh weight (FW)). According to the published data, only the determination of total polyphenols by Folin-Ciocalteu colorimetry in cow pea and snow pea exists [22]. For the free-form phenolics, p-hydroxybenzoic acid was the only phenolic acid detected in green soy bean and soybean sprouts. ...
Article
Full-text available
Phenolic acids are thought to be beneficial for human health and responsible for vegetables’ health-promoting properties. Free, conjugated, and bound phenolic acids of seven commonly consumed vegetables, including kidney bean, cow pea, snow pea, hyacinth bean, green soy bean, soybean sprouts and daylily, from the regions of Beijing, Hangzhou, and Guangzhou, were identified and quantified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Three vegetables, namely green soy bean, soybean sprouts, and daylily (Hemerocallis fulva L.), from the Beijing region contained higher concentrations of total phenolic acids than those from the Hangzhou and Guangzhou regions. The results indicated that the phenolic acid content in the seven vegetables appeared to be species-dependent. The highest content of phenolic acids was found in daylily, followed by green soy bean, while the least amounts were identified in kidney bean and hyacinth bean. Typically, phenolic acids are predominantly found in conjugated forms. Principle component analysis (PCA) revealed some key compounds that differentiated the seven vegetables. Green soy bean, compared to the other six vegetables, was characterized by higher levels of syringic acid, ferulic acid, vanillic acid, and sinapic acid. Other compounds, particularly p-coumaric acid, neochlorogenic acid, and caffeic acid, exhibited significantly higher concentrations in daylily. In addition, p-coumaric acid was the characteristic substance in cow pea. Results from this study can contribute to the development of vegetables with specific phytochemicals and health benefits.
... Also, a decrease in b-carotene content was observed at high PT and DT. It is believed that the decrease of b-carotene content at high PT could be due to thermal degradation, whereas during high DT could be due to oxidation by air and light exposure (Wen et al. 2010) in addition to thermal degradation. This can be due to the high heat sensitivity inherent to the highly unsaturated chemical structure of carotenoids (Rawson et al. 2011). ...
Article
Full-text available
The aim of this work was to optimize the effect of the precooking time (PT; 0, 4 and 8min), and the drying temperature (DT; 60, 72 and 84C) on physicochemical, microstructural and nutritional characteristics of winter squash flours (WSF). A hot-air dryer was used, and for data analysis, the response surface methodology was applied. As PT and DT were increased, β-carotene content, water absorption index (WAI), water solubility index, and the equilibrium moisture time were diminished, whereas total color difference was increased. SEM analysis showed cell disruption as DT was increased. The WSF obtained at optimal conditions (PT=2min; DT=72C) showed high WAI values, high content of bioactive compounds and antioxidant activity, and good sensory acceptability of a prepared product (creamy soup). Therefore, it could be proper the inclusion of WSF for the nutraceutical enrichment of ready-to-eat foods such as snacks, desserts and creamy soups. Practical Applications: The winter squash flours obtained by the optimized precooking-air-drying process can be used as ingredient for manufacturing different prepared food with potential health benefits, such as ready-to-eat-type food, enriched snacks, desserts and creamy soups, all of them with improved physicochemical properties (high water absorption) and content of bioactive compounds (β-carotene, dietary fiber and phenolic compounds).
... maxima. The decrease in phenolic compounds after blanching and boiling was in accordance with the studies of Myojin et al. (2008), Amin et al. (2006), Wen et al. (2010) and Miglo et al. (2008). These researchers reported that the phenolic compounds in the vegetables studied were sensitive to heat and the heat treatment caused a significant loss of phenolic content which leached into the water. ...
Article
Full-text available
The antioxidant properties of whole fruits and fruits without seeds and pith of two varieties of Momordica charantia (commonly known as bitter gourd), var. minima and var. maxima were investigated. The antioxidant content was investigated using ascorbic acid and total phenolic contents whereas the antioxidant activity was investigated using 2,2-diphenyl-1-picryl hydrazyl radical scavenging activity and ferrous ion chelating activity. The results showed that the fruits without seeds and pith and whole fruits of the two varieties of Momordica charantia exhibited different antioxidant content and activities. The ascorbic acid content ranged from 8.12 mg/100g to 24.46 mg/100g whereas the total phenolic content ranged from 1.47 mg GAE/100g - 27.23 mg GAE/100g. The antiradical power ranged from 4.67 to 5.94 and the ferrous ion chelating activity using the fruit extract concentration of 0.34 g/mL ranged from 10.6% to 89.3%. The effect of blanching and boiling on the antioxidant properties of fruits without seeds and pith of Momordica charantia var. maxima and minima was also investigated. Blanching and boiling of fruits without seeds and pith of M. charantia var. maxima and var. minima induced changes in the antioxidant content differently. The radical scavenging activity of the fruits without the seeds and pith of M. charantia var. maxima and var. minima increased as a result of blanching and boiling but their ferrous ion chelating activity became undetectable. There was no clear correlation between the antioxidant content and the antioxidant activities.
... In many developing countries, the largest contribution of vitamin A intake comes from the provitamin A carotenoids in plant foods, which may contribute up to 82% of the total vitamin A intake, whereas the contribution from fish and meat is of minor importance, because these foods are expensive and/or are not accessible (van den Berg et al., 2000). Malaysians mostly consume green vegetables such as Chinese mustard leaves, Chinese kale, lettuce, spinach and swamp cabbage (Amin and Cheah, 2003;Wen et al., 2010). According to the Nutrient Composition of Malaysian Foods (Tee et al., 1997), these green vegetables have been found to contain about 1825-4760 μg of β-carotene/100g edible portion. ...
Article
Full-text available
Green leafy vegetables are good sources of carotenoids. Generally, food composition databases related to raw foods are available, but data on cooked foods in Malaysia are still lacking. Since carotenoids are prone to degradation during cooking processes, the present study was undertaken to evaluate the extent of nutrient loss in vegetables subjected to two conventional cooking methods, which were boiling and stir-frying with cooking durations of 4 and 8 minutes. The vegetables selected were Chinese cabbage (Brassica Pekinensis var. cephalata), swamp cabbage (Ipomoea aquatica), spinach (Spinacia oleracea), Ceylon spinach (Basella rubra), red spinach (Amaranthus gangeticus), white spinach (Amaranthus viridis) and tapioca shoots (Manihot utilissima). Percentage losses of nutrients after cooking treatment were calculated based on retention factors. Results obtained showed that stir-frying had reduced lutein content for all vegetables ranging from 8-89% while the effect of boiling for lutein varied (0-428%) with different vegetables at bothcooking durations of 4 and 8 min. Boiling for 8 min increased retention of β-carotene in all vegetables ranging from 18-380% except for Chinese cabbage and spinach compared with 4 min, while stir-frying generally increased the retention of β-carotene for all vegetables 2-3 times except for spinach. Cooked vegetables have variations in carotenoids composition brought by varying cooking conditions (time and temperature), type of vegetables and the interaction between cooking methods and type of vegetables.
... The yield of methanol extract and TPC value increased slightly in the osmo-dried EFY, but this increase was not significant. It could be because of the tannin breakdown (Crozier, Lean, McDonald, & Black, 1997) or increased extractability because of heating temperature (Wen, Prasad, Yang, & Ismail, 2010) during OD. The TFC and AOA of optimized sample significantly decreased may be due to breakdown or eruption by water and heat (Park & Kim, 1995) during OD. ...
... This extract was used for subsequent assays. Total antioxidant activity was evaluated by DPPH radical scavenging assay (Wen, Prasad, Yang, & Ismail, 2010). Total phenolic content was evaluated in accordance with Folin Ciocalteu procedure (Han et al., 2011). ...
... AA is especially vulnerable to oxidative and enzymatic degradation in raw fruits and vegetables in which endogenous enzymes are active (Redmond et al., 2003;Francisco et al., 2010;Munyaka et al., 2010a;Wen et al., 2010;Cocetta et al., 2014). Significant and variable post-harvest loss of vitamin C in many fruits and vegetables stored under less optimal conditions has been reported (e.g., Gonzá lez et al., 2003;Lee and Kader, 2000;Munyaka et al., 2010a;Neves et al., 2015;Rybarczyk-Plonska et al., 2014;Szeto et al., 2002;Tiwari and Cummins, 2013;Veltman et al., 2000;Zee et al., 1991). ...
Article
Vitamin C loss was compared in homogenized raw broccoli, potatoes, spinach, strawberries, oranges, and tomatoes; baked potatoes; steamed broccoli and spinach; and pasteurized orange juice after storage under residual nitrogen under refrigeration, and frozen at conventional (-10 to -20. °C) and ultra-low (<-55. °C) temperatures for 1, 3, and 7 days. Additional foods (cantaloupe, green sweet peppers, collard greens, clementines) were monitored for 3-4 years at <-55. °C. Total ascorbic acid was quantified using high-performance liquid chromatography and detailed quality control measures. No decrease occurred in any of the foods after 7 days at <-55. °C. Under refrigeration the largest decreases were in raw spinach and broccoli, averaging (mg/100. g) 9.5 (29%) and 33.1 (29%), respectively, after 1 day and 31.0 and 77.0 after 7 days (94% and 68%, respectively). With conventional freezing, vitamin C was stable for 7 days in most of the products studied; minor losses occurred in raw spinach and broccoli after 1 day but were substantial after 3 days, 6.9. mg/100. g (23%) and 17.0. mg/100. g (15%), respectively; and 7 days (13.1 and 32.0. mg/100. g). For homogenates stored long-term at <-55. °C, vitamin C loss occurred in only cantaloupe, collard greens, and one sample of raw potatoes, all before 50 weeks.
... To meet the food safety and shelf life-stable requirements, however, thermal processing may involve long time heating at high temperatures, promoting chemical and physical reactions in foods, and rendering the product unwholesome or causing quality degradation (Fellows 2009). For example, color changes, development of off-odors or off-taste, and loss of freshness or nutrients occur frequently during and after thermal processing (Liaotrakoon et al. 2013;Song et al. 2003;Wen et al. 2010;Zabbia et al. 2011). It is particularly true for prepackaged solid or semisolid foods in which heat transfer is slow and the center temperature is difficult to raise when using conventional surface heating methods. ...
Article
Full-text available
Thermal treatments are extensively used in the food industry for control of pathogenic and spoilage microorganisms and spoilage enzymes. Food quality degradation during those treatments can be a major concern for consumer acceptance. Kinetic studies and mathematical models on quality changes of foods are essential in proper design of thermal treatments to ensure consumer satisfaction. This study provides a comprehensive review of recent progresses on quality kinetics for thermal treatments to inactivate microorganisms and enzymes in foods of both plant and animal origins. This paper mainly covers the theoretical basis for studying quality kinetics, common and special kinetic models to describe major quality attributes, such as appearance, texture, and nutrients, and potential applications of quality kinetic models to developing thermal treatment protocols. Finally, this review describes the challenges in quality kinetic studies and proposes recommendations for future research to maintain food quality and extend shelf life.
... The sample B and C having higher amount of total phenolics showed the higher antioxidant activity (Table 4). Wen et al. (2010) stated that the total phenolic content was positively correlated with the antioxidant activity of the vegetables like four-angled bean, French bean, long bean, snow pea and snap pea to some extent. Generally, the antioxidant potential of vegetables is affected by thermal processing. ...
Article
The aim of this research was to evaluate sensory quality of canned cauliflower pickles having different ingredients in their brines and the losses occurred in nutritive value especially in total phenolics and antioxidant activity due to processing. For this purpose, cauliflower florets were blanched in water containing NaCl (0.1%), Ca-ascorbate (0.25%), citric acid (0.1%), ascorbic acid (0.5%) and sodium metabisulphite (160 ppm) for inhibiting enzymatic browning. Six different brines consisting of, salt (4%), Ca-ascorbate (0.25%), acetic acid, (1%) lactic acid (1%), citric acid (1%) and their combinations with L-c cysteine (0.25%) were used. The samples were pasteurized at 98°C for 30 min. Head space, net and drained weight, colour (L*, a*, b*), total dry matter, total acidity, salt, SO2, total phenolics and antioxidant activity analysis were done. Blanching and pasteurization significantly reduced the total phenolic compounds levels by 7.12 - 14.78 %. The lowest and the highest reduction ratio of the antioxidant activity were determined in the sample including citric acid and the control sample as 2.90 and 72.79% respectively. Although L - cysteine affected visual appearance and colour positively, it affected taste and odour negatively. While acetic and citric acid containing samples were preferred for odour, acetic and lactic acid containing samples were preferred for taste criteria. Also lactic acid containing sample was preferred for hardness (p < 0.05).
... Although the phenolic content was determined to be higher in WB treatment than in EO, there were no statistically significant differences in dry matter content (Table 1). In a previous study, Wen et al. [2010] explained that blanching process had different effects on different vegetables, and while some vegetables showed increased phenolic content, others revealed a decreasing phenolic content. ...
Article
Full-text available
Background. The strawberry tree (Arbutus unedo L.) fruit contains a higher amount of nutrients and bioactive compounds than many other cultivated species, however, the edi-ble use of this fruit is currently not widespread. In this study, the influences of vacuum drying have been investigated in terms of changing of some nutritional characteristics, an-tioxidant properties, and colour. Material and methods. Fruits were collected from Çanakkale province in Turkey and next vacuum dried. Ethyl oleate and water blanching pre-treatments were applied to fruits before drying. Ascorbic acid, reducing sugar, minerals, colour, total phenolic content, DPPH radical scavenging activity, β-carotene bleaching activity and HMF formation were determined. Results. The EO pretreatment shortened the drying time more than WB and gives a high-er β-carotene bleaching activity, lower HMF and higher yellowness and brightness of ex-ternal colour characteristics. Conclusions. In this research, the effects of vacuum drying process on the colour, antiox-idant activity and nutritional characteristics of fruit have been determined and it has been concluded that the strawberry tree fruit is assessable in food industry by drying due to rich nutritional components, antioxidant activity and attractive colour of the fruit.
... Peas have the potential to provide high antioxidant compounds other than polysaccharides, proteins, and micronutrients. Generally, phenolics found in fruits and vegetables are bonded to dietary fibers, proteins, or to sugars in plants to form complex structures (Wen et al. 2010). Sultana and Anar (2008) reported the presence of flavanols such as kaempeferol, querecetin and myricetin in the pea seeds. ...
Article
A wide variety of waste bioresources are available on our planet for conversion into bioproducts. In the biological systems, microorganisms are used to utilize waste as an energy source for the synthesis of valuable products such as biomass proteins and enzymes. The large quantities of byproducts generated during the processing of plant food involve an economic and environmental problem due to their high volumes and elimination costs. After isolation of the main constituent, there are abundant remains which represent an inexpensive material that has been undervalued until now. Pea peel waste is one of the undervalued, unused sources of energy that can serve as a potential source for cellulase production. Batch experiments have been performed, using pea peel waste as a carbon source for cellulase production under solid state cultivation by Trichoderma reesei. It was observed that 30 o C temperature and pH 5.0 are the most favorable conditions for cellulase production by T. reesei. FPase activity significantly increases by incorporation of whey as well as wheat starch hydrolysate in the basal salt media used in the production study. The present study describes the utility of pea peel waste, whey as well as wheat starch hydrolysate in cellulase production by T. reesei. The utilization of economically cheap, pea peel waste for cellulase production could be a novel, cost effective, and valuable approach in cellulase production as well as in solid waste management.
... Conversely, blanching in boiling water increased total polyphenolic contents of kale (64.65%) and white cabbage (8.44%) ( Table 1). Wen et al. [15] reported that the blanching process showed different effects on different vegetables and some vegetables increased their polyphenolic content while others decreased. Sahlin et al. [16] showed that boiling and baking had a small effect on the ascorbic acid, total polyphenolic, lycopene, and antioxidant activity of the tomatoes, while frying significantly reduced the ascorbic, total phenolic, and lycopene contents of the tomatoes. ...
Article
Full-text available
The aim of this study to investigate the effect of different cooking methods (boiling, steaming, stir-frying, and microwaving) on the total polyphenolic content and total antioxidant activity of selected vegetables (beet, red cabbage, broccoli, white cabbage, black radish, kale, turnip, and red radish) from Turkey. A wide variation on total phenolic content was observed in raw vegetables, ranging from 44.94 ± 0.47 (beet, Beta vulgaris L. subsp. vulgaris) to 350.94 ± 5.18 (red radish, Raphanus sativus L.) μg gallic acid equivalent/mg of sample. Considering uncooked vegetables, the order of total antioxidant activity determined by β-carotene bleaching assay was beet > red cabbage > broccoli > white cabbage > black radish > kale > turnip > red radish. In DPPH• assay, kale had an exceptionally high antioxidant activity followed by red cabbage, broccoli, turnip, black radish, beet, white cabbage, and red radish.
... Antioxidant activity of food samples are affected largely based on different drying treatments. Vitamin C, carotenoids, phenolic compounds and antioxidant vitamins are sensitive to heat and light and could easily is destroyed during drying due to thermal degradation and oxidation (Wen et al. 2010;Yang et al. 2008). Hence, novel drying technologies like freeze drying, spray drying, and vacuum drying among others are used (Sagar and Kumar 2010). ...
Article
Full-text available
This study was aimed to investigate the antioxidant capacities of four common forage legume leaves namely, Arachis pintoi (Pintoi), Calapogonium mucunoides (Calapo), Centrosema pubescens (Centro), and Stylosanthes guanensis (Stylo). Two different drying methods (oven-drying and freeze-drying) were employed and antioxidant activities were determined by DPPH, Ferric Reducing Antioxidant Power (FRAP) and β-carotene bleaching assays. Total phenolic content (TPC) was determined using Folin-Ciocalteu assay. Freeze-dried extract showed the highest antioxidant activities by DPPH (EC50 values 1.17–2.13 mg/ml), FRAP (147.08–246.42 μM of Fe2+/g), and β-carotene bleaching (57.11–78.60%) compared to oven drying. Hence, freeze drying treatment could be considered useful in retention of antioxidant activity and phenolic content.
... This solution was used for subsequent assays. Total antioxidant activity was evaluated by DPPH radical scavenging assay (Wen, Prasad, Yang, & Ismail, 2010). Total phenolic content was evaluated in accordance with FolineCiocalteu procedure (Han et al., 2011). ...
... The results indicated steam blanching as less effectual pre-treatment in retaining polyphenol content than hot water blanching. This could be due to loss of heat sensitive polyphenolic compounds in the vegetables during steam blanching (Myojin et al., 2008;Wen, Prasad, Yang, & Ismail, 2010). ...
Article
Solar drying increases the quality and shelf life of the food product. In this study, three drying methods (solar, hot air, and sun drying) were used to evaluate the physicochemical properties of dried green colored vegetables (bitter gourd and capsicum). In addition, drying treatment was coupled with blanching (hot water and steam) as pre-treatment. It was found that the maximum functional compounds (flavonoid and polyphenol) were retained in solar dried bitter gourd (0.43 ± 0.02 RE mg/g; 0.12 ± 0.01 GAE mg/100 g) and capsicum (1.15 ± 0.11 RE mg/g; 1.29 ± 0.01 GAE mg/100 g), respectively. Moreover, nutritional quality (vitamin A & C) was higher in solar dried (1.50 ± 0.10 I.U., 3.95 ± 0.01 I.U.; 33.2 ± 0.3 mg/100 g, 49.8 ± 0.1 mg/100 g) in comparison to hot air and open sun dried vegetables. However, hot water blanched vegetables showed significant less degradation of polyphenols, flavonoids, and chlorophyll (p > 0.05) in relation to steam blanched vegetables in combination with solar drying. Also, solar dried vegetables attained the highest score of sensory acceptability. Therefore, it can be concluded that solar drying could be an effective technique over hot air and open sun drying for retaining better quality of dried vegetables.
... The essence of studying the correlation between TPC, TFC and antioxidant activity was to insinuate that the phenolic compounds in C. gynandra are highly responsible for its antioxidant activity. A number studies have reported positive correlations between phenolic compounds and antioxidant activity [54], [55], [56], and [57]. ...
Conference Paper
Full-text available
Cleome gynandra is an underutilised leafy vegetable that has a high nutritive value and contains phenolic compounds that are essential in reducing or preventing the occurrence of chronic and infectious diseases. Cooking and drying of the vegetable may induce changes to the vegetable’s phenolic content, antioxidant and antibacterial activity. C. gynandra was subjected to boiling, steaming, blanching and drying processes and analysed for its Total Phenolic Content (TPC), Total Flavonoid Content (TFC), antioxidant and antimicrobial activity as well as Fourier transform infrared spectroscopy (FTIR). Cooking and drying significantly (p < 0.05) increased the levels of phenolic compounds and antioxidant activity in the vegetable. Antibacterial activity was generally negatively affected by cooking while drying improved the activity. Cooking and drying exerted positive effects on the vegetable’s phenolic content and hence its importance in preventing and reducing chronic diseases is enhanced.
... The pictorial representation of Table 2 is given in Fig. 6 Polyphenol content: The results also showed significant decrease in the polyphenol content in case differently treated and differently dried mint. The decrease in phenolic compounds was in accordance with the studies of Myojin et al. (2008) and Wen et al. (2010). These researchers reported that the phenolic compounds in the vegetables studied were sensitive to heat and the heat treatment caused a significant loss of phenolic content which leached into the water (Fig. 7). ...
Article
Full-text available
One of the processes to increase the shelf life of the food products is drying and dehydration. Vegetables may be dried by different methods like solar drying, open sun drying and other mechanical methods so that they can be available during the lean season. In this study, mint was subjected to drying after giving two different treatments and their respective physical and chemical parameters were evaluated. An increase in chlorophyll content, flavonoid content and Vitamin A content was observed in all of the dried samples as they become concentrated source of nutrients. However, a decrease in polyphenol content and Vitamin C content in all of the samples was found. Drying rate of solar dryer was higher than hot air dryer and open sun drying. The aroma of dried mint was maintained in solar dried samples but was lost in hot air dryer and open sun drying.
... The fact that the plant is being used as folk medicine for the treatment of mental disorders, including depression, reinforced this hypothesis [24,26]. In this study, we preferred ethanol extraction because it is known to be a method for obtaining broad spectrum fractions, including phenolic compounds [37]. Imipramine, which we used as a reference, was found to be effective at a dose of 10 mg/kg in other studies [38]. ...
Article
Full-text available
Background: The flowering parts of Gentiana olivieri, known as ‘Afat’ in the southeastern Anatolia region of Turkey, are used as a tonic, an appetizer, and for the treatment of several mental disorders, including depression. The purpose of this study is to investigate the antidepressant effect of G. olivieri ethanol extract (GOEE) in a chronic mild stress-induced rat model, which was used to mimic a depressive state in humans, and to compare the effect with that of imipramine. Methods: Male Sprague-Dawley rats were randomly divided into six groups: control, stress, treated with imipramine (positive control) and treated with GOEE at three different (200, 500, 1000 mg/kg) doses groups. The rats in all groups, except the control group, were exposed to chronic mild stress. At the end of the 3-week experimental period, biochemical and behavioral parameters were examined. Results: The results showed that treatment with GOEE or imipramine significantly improved rats’ sucrose consumption which was diminished by chronic mild stress, restored serum levels of corticosterone and proinflammatory cytokines (interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α)), prevented the increase of liver index of rats. Moreover, in the hippocampus tissue, decreased serotonin and noradrenaline levels were significantly increased by treatment with GOEE or imipramine, and antioxidant parameters (thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), and glutathione (GSH)) were significantly improved by treatment with GOEE though not with imipramine. Conclusion: The data demonstrate that G. olivieri may exert its antidepressant activity by improving monoaminergic system disorders, and by favorably affecting the antioxidant, inflammatory and the endocrine mechanisms.
... Leafy vegetables were blanched in boiling water in a three-legged pot (cast iron) and spread on a corrugated roof iron for sun-drying. There are some evidence that blanching vegetables reduce antioxidant activity (Wen et al., 2010) and vitamin C (Lee et al., 2018). Sun-drying as a method of preservation for vegetables, fruits and meat reduces moisture content (Faber et al., 2010) and thus reduction in microorganism activity. ...
... On the other hand, the TPC of squash, peas and leek significantly reduced by the same level in all cooking methods. On the same, Wen et al. [24] communicated that the total phenolic content of vegetables increased and for some vegetables it decreased when blanched. Likewise, cooking methods were found to significantly affect the total polyphenol content on kale, white cabbage, red radish, beet, black radish, turnip, red cabbage and broccoli. ...
Article
Full-text available
Objective To investigate the effect of cooking temperature and time on the total phenolic content, total flavonoid content and antioxidant activity of aqueous and ethanolic extracts of garlic. Results The mean total phenolic content of fresh garlic were 303.07 ± 6.58 mg gallic acid equivalent per 100 g (GAE/100 g) and 638.96 ± 15.30 mg GAE/100 g of plant material for the aqueous and ethanolic extracts respectively. The mean total flavonoid content 109.78 ± 6.78 mg quercetin equivalent per 100 g (QE/100 g) and 258.47 ± 12.37 QE/100 g for aqueous and ethanolic extracts respectively. Fourier transform infrared spectral data showed absorptions in the range for carboxylic acids, hydroxyl group, esters, and alcohols, confirming the presence of phenols and flavonoids in the extracts. Cooking temperature had a significant effect on total phenolic content and total flavonoid content while cooking time did not have a significant effect on the phytochemicals and antioxidant activity.
... the physical and chemical properties and bioavailability of functional compounds in vegetables (Turkmen et al., 2005;Wen et al., 2010). ...
Article
The boiling process caused decrease from 22.22 mg/100 g to 3.01 mg/100 g in total phenolic content of celery root. Similarly, after boiling process, antioxidant activity of sample reduced from 2.67% to 0.53%. The main phenolic compounds of celery were found as catechin (50.93 mg/100 g), 3,4‐dihydroxybenzoic acid (39.81 mg/100 g), 1,2‐dihydroxybenzene (35.19 mg/7100 g), and gallic acid (19.21 mg/100 g), respectively. Generally, the reduction in phenolic compounds was observed with boiling process. The highest reduction was determined in 3,4‐dihydroxybenzoic acid from 39.81 mg/100 g to 30.62 mg/100 g. Additionally, gallic acid and quercetin contents of celery decreased from 19.21 mg/100 g to 15.75 mg/100 g and from 17.28 mg/100 g to 13.08 mg/100 g, respectively, while catechin content of sample increased from 50.93 mg/100 g to 54.77 mg/100 g after boiling process. A significant decrease in the total phenol and antioxidant activity values of boiled samples was observed. Celery is a rich source of natural active compounds having different biological properties and mechanism of action. The boiling process impacts the physical and chemical properties and bioavailability of functional compounds in vegetables. Most of the vegetables are cooked by boiling in water before consumed. This cooking process would bring about a number of changes in physical and chemical characteristics of vegetables. The present research was carried out for evaluation effects of antioxidant capacity, total phenolic, and phenolic compounds of the celery root by boiling cooking method compare to fresh.
... Consequently, a higher quantity of phenolic compounds, proanthocyanidin and flavonoids were observed in the ethanol samples when compared to the acetone, blanched and aqueous extracts; hence, better activity. This is in agreement with previous reports that ethanol is more suitable for the extraction of phenolic compounds in plants [30][31][32] . Furthermore, high phenolic compounds were indicated in ethyl acetate and methanol extracts, suggesting the reason for its high antioxidant activity 13 . ...
Article
Full-text available
Background: Heteromorpha arborescens (Spreng.) Cham. and Schltdl (Apiaceae) is widely used traditionally for the treatment of a wide range of diseases in Southern and Eastern Africa. Although previous studies have reported the biological activities of hexane, ethyl acetate and methanol extracts of H. arborescens leaves, there is no scientific information on the phytochemical contents, antioxidant and antibacterial activities of acetone, ethanol, aqueous and blanched extracts. This study is therefore aimed to investigate and compare the phytochemical contents, antioxidant and antibacterial activities of acetone, ethanol, aqueous and blanched extracts of H. arborescens leaves. Methods : Phytochemical analysis for the total phenolic, flavonoid, proanthocyanidin, alkaloid and saponin contents of all the fractions were determined by spectroscopic methods, while the free radical scavenging potential of the extracts were evaluated using DPPH, ABTS radical scavenging and total antioxidant capacity assays. Micro dilution method was used to determine the Minimum Inhibitory Concentrations (MIC) of H. arborescens leaf extracts against Bacillus pumilus, Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae . Results : Total phenol content of the extracts ranged between 15.10 mg GAE/g- 42.50 mg GAE/g, proanthocyanidin was 459-8402.1 mg QE/g, and flavonoid content of 109.24-235.79 mg QE/g. In addition, alkaloids (5.59%) and saponins (23.33%) were present in significant amounts. Based on the IC 50 values, the ethanol extract exhibited the highest total antioxidant activity (0.013 mg/mL) with highest inhibition against DPPH and ABTS radicals (0.06 and 0.049 mg/mL respectively). Considerable antibacterial activities were observed in the acetone, ethanol and blanched extracts with MIC values ranging from 1.563-12.5 mg/mL; however, the aqueous extract was inactive against all the bacteria strains. Conclusion : The study suggests that H. arborescens leaves could be a valuable source of bioactive compounds. Although the blanching process significantly decreased polyphenolic contents and antioxidant activities of the extracts, it increased the antibacterial compounds.
... Although the phenolic content was determined to be higher in WB treatment than in EO, there were no statistically significant differences in dry matter content (Table 1). In a previous study, Wen et al. [2010] explained that blanching process had different effects on different vegetables, and while some vegetables showed increased phenolic content, others revealed a decreasing phenolic content. ...
Article
Full-text available
Background. The strawberry tree (Arbutus unedo L.) fruit contains a higher amount of nutrients and bioactive compounds than many other cultivated species, however, the edible use of this fruit is currently not widespread. In this study, the influences of vacuum drying have been investigated in terms of changing of some nutritional characteristics, an-tioxidant properties, and colour. Material and methods. Fruits were collected from Çanakkale province in Turkey and next vacuum dried. Ethyl oleate and water blanching pre-treatments were applied to fruits before drying. Ascorbic acid, reducing sugar, minerals, colour, total phenolic content, DPPH radical scavenging activity, β-carotene bleaching activity and HMF formation were determined. Results. The EO pretreatment shortened the drying time more than WB and gives a higher β-carotene bleaching activity, lower HMF and higher yellowness and brightness of external colour characteristics. Conclusions. In this research, the effects of vacuum drying process on the colour, antiox-idant activity and nutritional characteristics of fruit have been determined and it has been concluded that the strawberry tree fruit is assessable in food industry by drying due to rich nutritional components, antioxidant activity and attractive colour of the fruit.
... In a previous study, researchers expressed that the boiling process had diverse effects on different vegetables. While some vegetables showed an increment in total phenolic contents, others exhibited a loss (Wen et al., 2010). ...
... Furthermore, the parenchymal cells from unblanched PS showed intact cell walls. In contrast, the cell walls of parenchymal cells from blanched PS were deformed suggesting that blanching could have disintegrated the cell walls, loosening the hemicellulose, cellulose and pectin networks of PS ( Fig. 2c and d) [51]. This could have increased the permeability of the PS cell walls and membranes to the solvent and therefore enhancing the mass transfer of the lipids into the extraction solvent. ...
Article
Full-text available
This study investigated the effect of cultivar and blanching of pomegranate seeds (PS) on quality attributes of the extracted oil. The quality attributes studied included oil yield, refractive index (RI), yellowness index (YI), conjugated dienes (K232), peroxide value (PV), ρ-anisidine value (AV), total oxidation value (TOTOX), total carotenoids content (TCC), total phenolic content (TPC), fatty acid composition, phytosterol composition, ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity. Three different cultivars of PS (‘Wonderful’, ‘Herskawitz’ and ‘Acco’) were blanched at 95 °C for 3 min. In each experiment, unblanched PS were used as the control. Blanching of PS improved oil yield, YI and DPPH radical scavenging capacity, while it decreased TCC, FRAP and TOTOX. The effect of blanching PS varied among the individual fatty acids and phytosterols. Interestingly, blanching of PS increased punicic acid content and the ratio of unsaturated to saturated fatty acid (UFA: SFA). The K232, RI and TPC of the oil extracts were not significantly (p > 0.05) affected by blanching. TPC was strongly correlated (r = 0.876) with FRAP. Principal component analysis established that ‘Wonderful’ and ‘Acco’ oil extracts from blanched PS were associated with oil yield, YI and β-sitosterol, whereas ‘Herskawitz’ oil extracts from blanched PS were correlated with punicic acid, FRAP and DPPH radical scavenging capacity. In conclusion, blanching ‘Wonderful’ and ‘Acco’ PS may improve oil yield, β-sitosterol content and colour, whilst blanching ‘Herskawitz’ PS may enhance the antioxidant capacity of extracted oil, which is beneficial in the cosmetic, nutraceutical, pharmaceutical and food industries.
... Thus, a higher quantity of phenolic compounds, proanthocyanidin and flavonoids were observed in ethanol samples than water hence, better activity. This agrees with other reports that ethanol is more suitable for the extraction of phenolic compounds in plants 37,38 . ...
Article
Full-text available
This study aimed at profiling the biological activities of Amaranthus caudatus cultivated on different soils in a glasshouse experiment. Five soil types namely; sandy clay loam, silty clay loam, clayey loam, loam and control (unfractionated soil) were experimentally formulated from primary particles of clay, sand and silt following the United State Department of Agriculture’s (USDA) soil triangle technique. After harvesting at pre-flowering (61 days after planting), flowering (71 days after planting) and post-flowering (91 days after planting) stages, crude extracts were obtained with water and ethanol. Total flavonoids, phenolic and proanthocyanidin contents of the extracts, as well as their biological activities, were determined using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2 diphenyl-1-picrylhydrazyl ethanol (DPPH), nitric oxide and phosphomolybdate assays. It was observed that biological activity of A. caudatus varied with soil types, stages of maturity and solvents of extraction. The highest phytochemical yield was recorded in ethanolic extracts of clayey loam harvested prior to flowering and the same trend was replicated in the antioxidant properties of the plant. For optimal biological activity, it is recommended that clayey loam soil should be used for cultivation of A. caudatus and harvest should be made near flowering to capture high phytochemical yield from the species.
... In our study we used two solvents for extraction of polyphenolic substances: methanol (Germany, Sigma Aldrich) and water. Methanol was chosen based on previous studies [8,13], while water was selected because it is the natural solvent in the human body [14]. The samples (morphological parts of tartary buckwheat) were incubated in methanol or water for 1 h at 60°C. ...
Article
Full-text available
In this report, we presented the profile of polyphenolic substances in flowers, leaves, stalk and roots of Fagopyrum tataricum estimated by using RP-UHPLC-ESI-MS equipment (reversed-phase ultra-high-performance liquid chromatography electrospray ionisation mass spectrometry). The neutral detergent fibre, acid detergent fibre, acid detergent lignin, cellulose and hemicellulose were also determined. Flowers, leaves, stalk and roots showed varying levels of dietary fibre and polyphenols. The highest content of neutral and acid detergent fibre were found in the roots (63.92 and 45.45% d.m., respectively) while the most rich in phenolic compounds were flowers (4.8 mg/1 g d.m.). Root and stalk contained the highest level of cellulose, 38.70 and 25.57% d.m., respectively. Among the investigated polyphenolic substances such as: 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 4-hydrobenzoic acid, caffeic acid, catechin, chlorogenic acid, fagopyrin, ferulic acid, myricetin, gallic acid, isovanilic acid, isovitexin, kaempferol, luteolin, p-coumaric acid, procyanidin B2, quercetin, quercetin 3-D galactoside, rutin, syringic acid and vitexin, we observed that the contents of rutin and chlorogenic acid were the highest. We found some correlation between dietary fibre fractions and individual phenolic substances. The levels of acid detergent fibre (ADF), cellulose and hemicellulose were negatively correlated with isovitexin, kaempferol, vitexin, fagopyrin, caffeic acid and procyanidin B2 content. In this investigation, two solvents (water and methanol) were estimated regarding their extraction efficiency of phenolic compounds. Taking these results into consideration, we recommend using methanol as the extractor to isolate chlorogenic acid, fagopyrin, kaempferol, procyanidin B2, quercetin, quercetin 3-D-galactoside, rutin, vitexin, and water for other investigated polyphenolic substances obtained from Fagopyrum tataricum.
... In some vegetables, blanching might actually improves the availability of the naturally occurring antioxidant components besides improving the palatability of the vegetable. Therefore, moderate blanching time and proper handling of vegetable are important in order to preserve the antioxidant properties [19]. ...
Article
Full-text available
The present study is aimed at analyzing the antioxidant activity using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) method and the texture using the Brookfield texture analyzer for blanched-solar dried, blanched-cooled with dehumidification, unblanched-solar dried, and unblanched-cooled with dehumidification mesocarps of two varieties of tender coconut, such as King coconut and Young coconut. Under the different treatments, there was a significant difference in the antioxidant activity and texture parameters such as “hardness” and “chewiness” at 5% level of significance. The highest (421.8 ± 12.33 mg/L) and the lowest (856.67±6.72 mg/L) antioxidant activities were recorded for blanched-solar dried mesocarp of King coconut and unblanched-cooled with dehumidification mesocarp of Young coconut, respectively. The texture analysis shows that there is a significant difference in the “hardness” and “chewiness” under different treatments at 5% level of significance. Among the treated mesocarps highest “hardness” value (6619.7±147.1) and “chewiness” value (1079.3±54.90) were recorded for King coconut blanched-solar dried mesocarp and lowest “hardness” value (595.67±36.88) and “chewiness” value (12.634±0.836) were recorded for Young coconut blanched-cooled with dehumidification mesocarp. Since the blanched-solar dried mesocarp of King Coconut has highest antioxidant activity and lowest “chewiness”, it is more suitable to develop a food product.
... Among the top 10 disease risk factors, improper consumption of fruits and vegetables has been considered as the prime most risk factor (Wen et al., 2010). It leads to the increase in the number of researchers working actively on the health benefits of fruits and vegetables in recent years (Khanam et al., 2012). ...
Article
Full-text available
In the present work, the impact of microwave pretreatment on the thermal degradation of color (chlorophylls) in mustard greens was studied. The drying experiments were conducted in the range of temperatures from 50 to 80°C. The degradation in the levels of chlorophylls has been quantified using Hunter color values (L*, a*, and b*) and calculating total color difference (ΔE). From the color results, the changes in color values (L*, a*, and b*) were observed as inappreciable, and changes in ΔE were found to be increased during drying. Analysis of kinetic data displayed a first-order reaction kinetics for chlorophyll degradation. Arrhenius equation was used to calculate the activation energies for rate constants, and it has been varied from 13.3 to 27.4 kJ/mol. Thermodynamic parameters, enthalpy of activation (ΔH#), and entropy activation (ΔS#) were found to be in the range of 1.40–2.63 J/mol and −293 to −305 J/mol · K, respectively. The data from the present work revealed that the microwave pretreatment of mustard greens remarkably influenced the retention of chlorophylls in the final dehydrated powder.
Article
Background: Cardiac failure is on the increase due to inadvertent exposure to both aquatic and terrestrial toxicants. It is one of the most common incapacitating, painful, and deadly ailment. Synthetic drug intervention of the disease has some negative impacts on the patients, which means that it is not completely safe to intervene with the artificial drugs, there is need for alternative safe therapeutic agents. However, phenolic compounds of Launea taraxacifolia may serve as a complementary medication against cardiac failure. The study therefore examines the protection of Launea taraxacifolia methanolic extract (LTME) on cardiovascular toxicity induced by metropolitan surulere polluted river water (SPRW). Method: Forty-eight (48) animals were divided into six groups (n = 8): Group I was orally given 1 ml of distilled water only; Group II received 1 ml of SPRW only; Group III (Pre-treated) received 200mg/kg LTME before + 1ml of SPRW after; Group IV (Co-treated) received 200mg/kg LTME + 1ml of SPRW; Group V (post-treated) received 1ml of SPRW before + 200mg/kg LTME after. Group VI received 200mg/kg LTME only. The experiment lasted for 28 days. Results: The generation of OH. radical and elevated activity of eco-5¹-nucleotidase, α-glucosidase, α-amylase, and aldose-reductase by SPRW intoxication was abrogated by LTME with corresponding LDH increase. Additionally, SPRW caused systemic alteration of CAT and SOD activity with decreased GSH level. The cardiomyocytes showed necrosis with the accumulation of inflammatory cells; indicating myocarditis compared to normal and treated groups. These abysmal were reversed by LTME treatment. The upregulation of α-glucosidase, α-amylase, aldose-reductase and eco-5¹ nucleotidase activities with low intracellular ATP in the heart may explain the underlying mechanisms of cardiovascular dysfunctions in rat exposed to SPRW toxicant. Conclusion: The treatment with active constituents from LTME may be the chemotherapy agent against cardiac necrosis.
Article
The present study was conducted in order to evaluate the effects of blanching on the total and individual phenolic and antioxidant activities of 4 young sprouts of medicinal plants: dureup (Aralia elata), caster aralia (Kalopanax pictus), tree-of-heaven (Cedrela sinensis), and ogapi (Acanthopanax sessiloflorus). Caster aralia and dureup displayed significant reduction of Fe2+ chelation following blanching, but no alteration of DPPH or ABTS radical scavenging activity. Blanched ogapi displayed lower Fe2+ chelation as well as decreased DPPH and ABTS radical scavenging activities compared to raw sample. In contrast, tree-of-heaven displayed significantly increased antioxidant activity after blanching. Major phenolic compounds in mountain vegetables were chlorogenic acid and vanillic acid. In particular, chlorogenic acid contents increased by 11.2–68.1% in all vegetables except for ogapi after blanching. The results of this study show that blanching might be a useful tool for improving the beneficial properties of tree-of-heaven.
Article
The antioxidant activity and content of phenolic substances in vegetable broths were determined. Green beans, beetroots, courgettes, onions, parsley, carrots, cabbages, celery, broccoli, spinach, cauliflowers, and tomatoes were subjected to boiling. Fresh vegetables and vegetable broths were analysed for ascorbic acid content, total phenolic content, ORAC and TEAC values. Phenolic acids were quantified using HPLC. The ascorbic acid content of vegetables ranged from 5–109 mg/100 ml, while no ascorbic acids could be detected in vegetable broths. Total phenolic content was between 17–1729 mg GAE/l for all samples. ORAC and TEAC values of vegetable broths were between 0–3 µmol TE/ml and 0–2 µmol TE/ml, respectively. Gallic, chlorogenic, caffeic, p-coumaric, and ferulic acid were detected in both fresh vegetables and vegetable broths. The highest phenolic acid content was observed in water in which beetroots were boiled. It was found that the vegetable broths of beetroots, celery stalks, cabbages, parsley and broccoli harboured remarkable antioxidant activity.
Article
The nutritive, physicochemical and technological characteristics of several intermediate food products (IFPs) from Spanish Confitera fresh date co-products were investigated. Three IFPs were obtained, two from unblanched dates in different ripening stages (Khalal and Rutab), and a third one from blanched Khalal fruits. The IFPs were rich in dietary fibre (13–16%, dry matter), phenolics (0.56–4.26 g GAE/100 g dry matter) and sugars (55–82%, dry matter), with glucose and fructose as the predominant sugars. Malic acid was the major organic acid, and potassium was the main mineral. Blanching Khalal dates aided to prevent browning in the IFP, but also the thermal treatment modified the sugars profile. The results indicated that both maturity stages yield IFPs with potential in the food industry; and according to their sugar and phenolic content they could be suitable for the elaboration of new ingredients with different industrial applications. In addition, it would be recommendable blanching unripe fruits.
Article
This study assessed the influence of blanching and frying heating rate/time on the antioxidant capacity and (poly)phenols of cardoon stalks (Cynara cardunculus L. var. altilis DC). Blanching (98 °C, 30 s) increased the total native chlorogenic acids content (1.2-fold vs raw cardoon), with no significant changes in DPPH antioxidant capacity, but with a decrease in ABTS antioxidant capacity (0.6-fold). Specifically, total di-caffeoylquinic acids (CQAs) increase (1.6-fold) counterbalanced the losses of 5-CQA (0.8-fold). All frying conditions (t85ºC = 5, 12 or 10 min, ttotal = 15, 15 or 30 min, respectively) decreased the antioxidant capacity (0.5–0.7-fold in DPPH, 0.5–0.9-fold in ABTS) of cardoon, but increased total flavonoid amount (3.6–3.7-fold) that remained at low levels. The Short (15 min) and Intense-heat Frying (t85ºC = 5 min) favoured the release of chlorogenic acids, particularly 5-CQA, from the food matrix. However, a longer frying process (30 min) induced an almost complete degradation of di-CQAs. Thus, it is desirable to limit the frying duration. When blanching and frying were combined, a higher thermal degradation of (poly)phenols was observed, but the Short and Intense-heat Frying remained the most suitable. This study highlights the importance of selecting optimal culinary conditions for vegetables that favour a high content on bioactive compounds and, therefore, their potential healthy properties.
Article
Pumpkin seed (Cucurbita pepo) otherwise known as pepitas serves as food and has several medicinal uses in many parts of the world. This study investigated the effect of roasting on the phenolic phytochemicals and antioxidant activities of pumpkin seeds. Reverse-phase HPLC analysis revealed that the seed had appreciable levels of caffeic acid, quinine, rutin, quercetin, and chlorogenic acid. Roasting caused a significant (P < 0.05) increase in the polyphenolic content; reducing power, iron-chelating ability, DPPH* (2,2 diphenyl-1-picrylhydrazyl radical), ABTS*+ [2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) radical cation], NO* (nitric oxide radical), OH* (hydroxyl radical) scavenging abilities; and SNP- (sodium nitroprusside) and Fe2+-induced lipid peroxidation inhibitory capacity of the seed extract. Thus, roasting enhanced the levels of these functional attributes of the seeds due to the release of phenolic phytochemicals, hence contributing to the health-promoting and disease preventing abilities of pepitas.
Article
Full-text available
Рассмотрены возможности получения загустителя для пищевых продуктов с одновременным их окрашиванием при помощи специальной подготовки водного экстрагента за счет контакта воды с природным материалом шунгитом, в состав которого входят фуллерены, представляющие собой аллотропную форму углерода.Представлены теоретические и практические исследования по разработке комплексной технологии выделения природных красителей из жмыха черной смородины, являющегося концентрированным природным сырьем антоциановых красителей. Установлено, что выделение природных красителей необходимо проводить в несколько стадий: 1-предварительная подготовка исходного сырья, 2-экстракция специально подготовленными водными экстрагентами при повышенной кислотности, 3-адсорбция на пищевом адсорбенте - крахмале. В качестве водного экстрагента предложена вода, предварительно обработанная природным материалом шунгитом, содержащем активные наноматериалы - фуллерены. Фуллерены - особая шаровидная форма углеродного материала с сопряженными связями. Одно из свойств фуллеренов – это его взаимодействие с водой. Известно, что кристаллическая форма не растворима в воде. Многие попытки получить водные растворы фуллеренов приводят к образованию коллоидных или грубодисперсных систем фуллерен – вода, в которых частицы содержат большое количество молекул в кристаллической форме. Получение водных молекулярных растворов кажется невозможным. А иметь такой раствор очень важно и в первую очередь для использования их в биологии и медицине. Доказано, что условия проведения экстракции существенно влияют на эффективность экстракции. Установлено, что проведение микроволнового воздействия на замороженную измельченную ягоду увеличивает выход красителя при экстракции на 14%. Использование шунгитовой воды, содержащей фуллерен в качестве экстрагента, резко (на 55%) повышает содержание красителя в экстракте.Представлен механизм получения цветного крахмала, модифицированного фуллереном, обладающего высокими антиоксидантными свойствами. Отмечено повышение экстрактивной способности этой воды по отношению к антоцианам. Установлено, что несмотря на наличие растительных источников антоциановых красителей их технология получения является очень энергозатратной, сложной и малоэффективной. Установлена возможность интенсификации экстрактивного процесса за счет предварительной обработки исходного растительного материала замораживанием, измельчением и кратковременной микроволновой обработкой. Предложен новый способ адсорбции антоцианов из экстрактов на пищевом углеводном материале - на картофельном крахмале. Это позволяет ликвидировать традиционные энергоемкие стадии технологии выделения природных красителей.
Article
Bioactive food components are active ingredients in food or dietary supplements proven to have a role in health and they are safe for human consumption. These compounds exert their antioxidant effects by different mechanisms such as hydrogen atom transfer (HAT) or single electron transfer (SET) and their efficiencies can be evaluated by several methods such as ferric reducing ability of plasma (FRAP), trolox equivalent antioxidant capacity (TEAC), dipheny-picrylhydrazil (DPPH), Folin-Ciocaltue method (FCM), etc. In this review, these mechanisms and methods will be discussed in details.
Article
Full factorial design was employed to study the effect of gamma irradiation (0–2.5 kGy) and storage (up to 28 d) at 10 °C on quality of RTC pumpkin. Data obtained from microbial, color, texture and sensory analysis were fitted into a cubic model. Resulting equations were solved to assess radiation dose and maximum storage period for acceptable microbial quality (< 105 CFU g− 1) and sensory scores (overall acceptability > 5). Radiation dose of 1 kGy resulted in a product with desired microbial and sensory quality up to storage period of 21 d. The processed product (1 kGy) had significantly (p < 0.05) higher total antioxidant and vitamin C content as compared to non-irradiated control after storage of 21 d. HPLC analysis demonstrated that there were no qualitative changes in phenolic and carotenoid constituents due to radiation processing. Thus radiation processing was successfully employed to develop RTC pumpkin with improved shelf-life.
Article
The aim of this study was to review prior studies that have evaluated the effects of cooking techniques on polyphenol levels and antioxidant activity in vegetables and to release a meta-analysis of the findings. Meta-analysis with a random effect model was conducted using the weighted response ratios (R*) that were calculated for each experiment. Baking (R* = 0.51), blanching (R* = 0.94), boiling (R* = 0.62), microwaving (R* = 0.54) and pressure cooking (R* = 0.47) techniques precipitated significant reductions in the polyphenol levels. Significant decreases in the antioxidant activity levels were noted after baking (R* = 0.45) and boiling (R* = 0.76), while significant increases were observed after frying (R* = 2.26) and steaming (R* = 1.52).
Article
Bok choy, Brassica rapa subsp. Chinensis, is a type of Chinese cabbage. Stir frying could affect antioxidant activity and aroma composition of bok choy. Antioxidant activity such as DPPH (diphenyl picryl hydrazinyl radical) and FRAP (ferric-reducing antioxidant power) of the leave and stem samples were determined. The highest FRAP activity was obtained at 1.5 min stir-frying under 160ºC for bok choy leaves (49.7±2.1µmol FeSO4/g DW). In FRAP assay, antioxidant capacities of bok choy stem samples increased significantly after stir-frying. Dimethyl sulfide (DMS), a typical volatile organic sulfur compound with a characteristic cabbage-like odor, was only observed in leave groups. After cooking treatment, antioxidant activities of bok choy stems were higher than those of leaves in DPPH assay. Odor-active compounds were identified using gas chromatography-olfactometry-mass spectrometry (GC-O-MS) technique. Compared to stem sample data, more aroma components were quantified in leaves sample in 160ºC, 180ºC and 210ºC respectively. It was first time to detect and analysis the aroma components and antioxidant activity in different edible part of bok choy after Chinese domestic cooking.
Article
Full-text available
Ground corn tassels, a by-product of corn, were used as a source of phenolic compounds. Water, ethanol, methanol, acetone, hexane, chloroform, butanol, petroleum ether and methylene chloride were evaluated as different polarity solvents to extract these phenolic compounds. Ethanol exhibited the highest extraction ability for such phenolic compounds, followed by methanol and water, where the total phenols were 0.1575%, 0.1125% and 0.0737%, respectively. Antioxidant activity of corn tassels ranged from 83.0% to 85.2%, 69.9% to 83.7%, 69.8% to 80.4%, 22.2% to 49.1% and 14.8% to 19.3% radical scavenging activity (% RSA) for ethanol, methanol, acetone, butanol and water extracts, respectively. The ethanolic extract of the corn tassels was successfully utilised to retard the oxidation of sunflower oil and the obtained induction period values were comparable to those of tert-butylhydroquinone (TBHQ).
Article
Full-text available
As consumer interest in organically grown vegetables is increasing in Malaysia, there is a need to answer whether the vegetables are more nutritious than those conventionally grown. This study investigates commercially available vegetables grown organically and conventionally, purchased from retailers to analyse β-carotene, vitamin C and riboflavin contents. Five types of green vegetables were selected, namely Chinese mustard (sawi) (Brassica juncea), Chinese kale (kai-lan) (Brassica alboglabra), lettuce (daun salad) (Lactuca sativa), spinach (bayam putih) (Amaranthus viridis) and swamp cabbage (kangkung) (Ipomoea aquatica). For vitamin analysis, a reverse-phase high performance liquid chromatography was used to identify and quantify β -carotene, vitamin C and riboflavin. The findings showed that not all of the organically grown vegetables were higher in vitamins than that conventionally grown. This study found that only swamp cabbage grown organically was highest in β -carotene, vitamin C and riboflavin contents among the entire samples studied. The various nutrients in organically grown vegetables need to be analysed for the generation of a database on nutritional value which is important for future research.
Article
Full-text available
Five different varieties of cauliflower (Brassica oleracea L. ssp. botrytis); two white (cv. ‘Aviso’, ‘Dania’), one purple (cv. ‘Grafitti’), one green (cv. ‘Emeraude’) and one romanesco/green pyramidal (cv. ‘Celio’) cultivar have been studied. All samples were thermally processed and the effects on the levels of glucosinolates (GLS), total phenols (TP), total monomeric anthocyanins (TMA), l-ascorbic acid (l-AA) and antioxidant capacities (FRAP and ORAC) were investigated. Processing methods applied were: blanching (3 min), boiling (10 min) and steaming (10 min). Total GLS were significantly (p < 0.05) affected by processing with the highest losses, 55 and 42% on average, occurring for boiled and blanched samples, respectively. Significant effects were also noted for steaming, but to a lesser extent, i.e. 19% average reduction. Antioxidant-related parameters were similarly affected with average losses of 27, 33, 36 and 46% in boiled cauliflower and 16, 21, 22 and 28% in blanched for TP, FRAP, l-AA and ORAC, respectively. Blanching and boiling reduced TMA in purple cauliflower by 38 and 53%, respectively. Steaming affected the antioxidant-related parameters the least for all cultivars. l-AA was significantly reduced by 14% in all cultivars by steaming. Some differences in behaviour between cultivars were noted, especially between white and coloured cultivars for TP, FRAP and l-AA, but also for some GLS. The main losses were caused by leaching into the processing water.
Article
Full-text available
In this work, pre-blanching of Brussels sprouts was performed – using different heating media – as well as various blanching times, in order to minimize quality factors losses and browning incidence in subsequent stages of product processing and storage. Sprouts were firstly treated for 5 min, either in water at 50 °C or by microwaves, and then blanched in boiling water for 3 or 2 min, respectively. Other samples were directly blanched by immersion in water (100 °C) for 1, 3 or 4 min. Thermal history, surface colour, texture, total chlorophyll, radical scavenging activity, ascorbic acid and total flavonoids content were determined. Microwaves pre-blanching showed no deleterious effects on total chlorophyll, radical scavenging activity, total flavonoids and ascorbic acid content of Brussels sprouts and the moderate heat treatment induced by this method may be considered to be a useful tool to improve health properties of Brussels sprouts.
Article
Full-text available
Effects of microwave and conventional cooking methods were studied on total phenolics and antioxidant activity of pepper, squash, green beans, peas, leek, broccoli and spinach. Total phenolics content of fresh vegetables ranged from 183.2 to 1344.7 mg/100 g (as gallic acid equivalent) on dry weight basis. Total antioxidant activity ranged from 12.2% to 78.2%. With the exception of spinach, cooking affected total phenolics content significantly (p < 0.05). The effect of various cooking methods on total phenolics was significant (p < 0.05) only for pepper, peas and broccoli. After cooking, total antioxidant activity increased or remained unchanged depending on the type of vegetable but not type of cooking.
Article
Full-text available
The antioxidant activities and total phenolics of 28 plant products, including sunflower seeds, flaxseeds, wheat germ, buckwheat, and several fruits, vegetables, and medicinal plants were determined. The total phenolic content, determined according to the Folin−Ciocalteu method, varied from 169 to 10548 mg/100 g of dry product. Antioxidant activity of methanolic extract evaluated according to the β-carotene bleaching method expressed as AOX (Δ log A470/min), AA (percent inhibition relative to control), ORR (oxidation rate ratio), and AAC (antioxidant activity coefficient) ranged from 0.05, 53.7, 0.009, and 51.7 to 0.26, 99.1, 0.46, and 969.3, respectively. The correlation coefficient between total phenolics and antioxidative activities was statistically significant. Keywords: Antioxidant activity; phenolics; medicinal plants; oilseeds; buckwheat; vegetables; fruits; wheat products
Article
Full-text available
Recent epidemiologic study results showed that subjects who had high intakes of whole-grain foods had lower risks of death and heart disease than did subjects who had low intakes. However, the findings were inconsistent for fruit and vegetable intake. The relations of whole-grain, refined-grain, and fruit and vegetable intakes with the risk of total mortality and the incidence of coronary artery disease (CAD) and ischemic stroke were studied in the Atherosclerosis Risk in Communities (ARIC) cohort (baseline: age 45-64 y, n = 15,792). Proportional hazards regression analyses were used to assess the relations of whole-grain, refined-grain, and fruit and vegetable intakes with the risk of death and the incidence of CAD and ischemic stroke, with adjustment for age, sex, ethnicity, energy intake, and cardiovascular disease risk factors. Dietary intakes were assessed by using a food-frequency questionnaire. Over an 11-y follow-up period, whole-grain intake was inversely associated with total mortality and incident CAD. The relative hazards of death for quintiles 2-5 of fruit and vegetable intake were 1.08 (95% CI: 0.88, 1.33), 0.94 (0.75, 1.17), 0.87 (0.68, 1.10), and 0.78 (0.61, 1.01), respectively; P for trend = 0.02. An inverse association between fruit and vegetable intake and CAD was observed among African Americans but not among whites (P for interaction = 0.01). The risk of ischemic stroke was not significantly related to whole-grain, refined-grain, or fruit and vegetable consumption. These observational findings suggest a beneficial effect of whole-grain and fruit and vegetable consumption on the risks of total mortality and incident CAD but not on the risk of ischemic stroke.
Article
There is currently much interest in phytochemicals as bioactive components of food. The roles of fruit, vegetables and red wine in disease prevention have been attributed, in part, to the antioxidant properties of their constituent polyphenols (vitamins E and C, and the carotenoids). Recent studies have shown that many dietary polyphenolic constituents derived from plants are more effective antioxidants in vitro than vitamins E or C, and thus might contribute significantly to the protective effects in vivo. It is now possible to establish the antioxidant activities of plant-derived flavonoids in the aqueous and lipophilic phases, and to assess the extent to which the total antioxidant potentials of wine and tea can be accounted for by the activities of individual polyphenols.
Article
The effects of soaking, boiling and steaming processes on the total phenolic components and antioxidant activity in commonly consumed cool season food legumes (CSFL's), including green pea, yellow pea, chickpea and lentil were investigated. As compared to original unprocessed legumes, all processing steps caused significant (p<0.05) decreases in total phenolic content (TPC), DPPH free radical scavenging activity (DPPH) in all tested CSFL's. All soaking and atmospheric boiling treatments caused significant (p<0.05) decreases in oxygen radical absorbing capacity (ORAC). However, pressure boiling and pressure steaming caused significant (p<0.05) increases in ORAC values. Steaming treatments resulted in a greater retention of TPC, DPPH, and ORAC values in all tested CSFL's as compared to boiling treatments. To obtain cooked legumes with similar palatability and firmness, pressure boiling shortened processing time as compared to atmospheric boiling, resulted in insignificant differences in TPC, DPPH for green and yellow pea. However, TPC and DPPH in cooked lentils differed significantly between atmospheric and pressure boiling. As compared to atmospheric processes, pressure processes significantly increased ORAC values in both boiled and steamed CSFL's. Greater TPC, DPPH and ORAC values were detected in boiling water than that in soaking and steaming water. Boiling also caused more solid loss than steaming. Steam processing exhibited several advantages in retaining the integrity of the legume appearance and texture of the cooked product, shortening process time, and greater retention of antioxidant components and activities. Copyright © 2008 Elsevier Ltd. All rights reserved.
Article
An HPLC study of 18 of the fresh vegetables (raw and cooked) most frequently consumed in Spain was done to determine their carotenoid composition. The results are grouped according to the color of the edible portion of each: green, red-orange, or yellowish-white vegetables. Beta-Carotene and lutein were found to be present in all of the vegetables analyzed except the sweet red pepper, which contains zeaxanthin but not lutein. Lutein and zeaxanthin are present in five of the vegetables analyzed, with the highest concentration of both of these components being found in spinach. In green and yellowish-white vegetables, lutein predominates over beta-carotene. Red-orange vegetables show a wider carotenoid profile, in which the lutein levels are surpassed by other carotenoids (e.g., lycopene in tomatoes, alpha- and beta-carotene in carrots). Boiling was not found to alter the carotenoid profile of the samples, but the amounts of carotenoids quantified were higher when compared to those in raw samples.
Article
The kinetics of ascorbic acid loss and nonenzymatic browning in clarified orange juice (serum) were investigated in an anaerobic environment from 70.3 to 97.6°C and from 11.7 to 80.6Brix. Data were fitted to firstorder kinetic models. Rate constants of ascorbic acid degradation in serum were not different from rate constants in whole juice. Activation energies were ±30 kcal/mol and largely independent of solids concentration. Rate constants of browning pigment formation were 30–50% greater in serum. Activation energies were 19–25 kcal/mol and increased slightly with solids concentration.
Article
Thermally processed fruits and vegetables have long been considered to have a lower nutritional value compared with the fresh produce. This consideration is based on the fact that vitamin C or other thermolabile compounds may lose their activity due to oxidation or in consequences of leaching into the water during home cooking or industrial processing, such as blanching. In this study, broccoli, one of the major agricultural products was exposed to steam; and total antioxidant activity was measured by oxygen radical capacity (ORAC) analysis and a cellular measure of reactive oxygen species (ROS) assay. The study also evaluated the level of total phenolics and total flavonoid content in fresh and steam processed broccoli samples. The result clearly showed that steam-processing elevated the total ORAC (hydrophilic, lipophilic) value by 2.3 fold. Measuring cellular levels of ROS, we found that the hydrophilic part of a steam processed broccoli had a significant reduction of 2,2′-azobis [2-amidinopropane] dihydrochloride (AAPH) induced intracellular ROS level in comparison to that of fresh counterpart. Total phenolic content and total flavonoid content also increased in steamed-processed broccoli. Chromatographic analysis showed that a non-phenolic fraction which appeared unbound on a cosmosil 140 C18 resin contributed 54%, and the phenolic pool eluted by 50–80% methanol contributed 41% of its total increase in ORAC value. Steam processed broccoli gave significant cytoprotection in PC-12 cell line and this neuroprotective efficacy warrant further investigation. This information may have a significant impact on consumers’ food selection, depending on the processing technology used to process agricultural products.
Article
The study was aimed to determine the antioxidant activity (total antioxidant and free radical-scavenging activities) and total phe-nolic content of Amaranthus sp. The effects of different blanching times (10 and 15 min) on antioxidant activity and phenolic content were also studied. Four types of Amaranthus species locally known as spinach, namely Ôbayam putihÕ (Amaranthus paniculatus) (BP), Ôbayam merahÕ (Amaranthus gangeticus) (BM), Ôbayam itikÕ (Amaranthus blitum) (BI) and Ôbayam panjangÕ (Amaranthus viridis) (BPG), were selected. Total antioxidant activity of water-soluble components in raw spinach was in the order of BI % BM % BPG > BP, whereas free radical-scavenging activity was in the order of BI > BPG > BM > BP. The total phenolic con-tents of BM and BP were significantly higher (p < 0.05) than other samples. All the studied spinach species possessed different anti-oxidant activities and phenolic contents. Antioxidant activities and phenolic contents of all the spinach were in the order of raw > blanched 10 min > blanched 15 min. Blanching up to 15 min may affect losses of antioxidant activity and phenolic content, depending on the species of spinach.
Article
As a promising technique, high-pressure extraction (HPE) method was used to extract bioactive compounds from litchi fruit pricarp. The study involved in different experimental factors such as solvent, ethanol concentration (35-95, v/v), material to solvent ratio (1:25-1:100, w/v), acidic medium, extraction pressure (200-500 MPa), time (2.5-30 min) and temperature (30-90 °C). The extraction yield, total phenolic contents, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and superoxide anion scavenging capability of the HPE sample were examined and then compared with those of ultrasonic extraction and conventional extraction samples. The application of HPE obtained higher extraction yield compared to other extraction methods. However, there were no significant differences (P > 0.05) in the total phenolic content and the antioxidant activities among these various extractions. Compared with some conventional extraction method, the HPE exhibited higher extraction efficiency in terms of higher extraction yield and extraction time.
Article
In this second part of our review, we examine the literature for changes in carotenoids, vitamin E, minerals, and fiber due to processing, storage, and cooking of fresh, frozen, and canned fruits and vegetables. While inconsistencies in methodology and reporting methods complicate interpretation of the data, the results show that these nutrients are generally similar in comparable fresh and processed products. The higher levels of carotenoids typically found in canned as compared to fresh products may be attributed to either reporting results on a wet rather than dry weight basis, greater extractability, or differences in cultivars. There are relatively few studies on processing, storage, and cooking effects on vitamin E in fruits and vegetables. Further research is needed to understand nutritional changes in those few fruits and vegetables rich in vitamin E, such as tomatoes. Minerals and fiber are generally stable to processing, storage, and cooking, but may be lost in peeling and other removal steps during processing. Mineral uptake (e.g., calcium) or addition (e.g., sodium) during processing can change the natural mineral composition of a product. Sodium concerns in canned food can be addressed by choosing products with no salt added. Since nutrient content varies considerably by commodity, cultivar, and postharvest treatments, inclusion of a wide variety of fruits and vegetables in the diet is encouraged. Copyright © 2007 Society of Chemical Industry
Article
The effect of microwave heating of extra virgin olive oil (EVOo), olive oil (Oo) and pomace olive oil (Po) in domestic appliances, was investigated in terms of chemical oxidative indices (peroxide, p-anisidine and Totox values), free acidity, water content, total phenol content and different classes of phenolic compounds.Water content of unheated EVOo was higher as compared to the other two oils and it was found to decrease with increasing treatment time in all oils, especially in EVOo. Lipolysis was noticeable in EVOo only at highest treatment times. p-Anisidine values showed a sinusoidal trend in EVOo and Oo with a maximum at 6 and 15 min, respectively, while they gradually increased in Po.Significant amounts of phenols were detected only in unheated EVOo, even though about 30% were lost after 6 min. Among the different classes of phenolic compounds, o-diphenols and lignans displayed the highest microwave heating resistance in the whole time range of microwave application, which is of great importance from a nutritional standpoint. The utilisation of Po may be encouraged especially at short microwave treatment times for both domestic and food catering applications.
Article
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.
Article
Red pepper has been recognised as an excellent source of antioxidants, being rich in ascorbic acid and other phytochemicals. Drying conditions, particularly temperature, leads to pepper modifications that can cause quality degradation. In this work, the effects of process temperatures between 50 and 90 °C on physico-chemical properties, rehydration, colour, texture, vitamin C, antioxidant capacity and total phenolics during the drying of red pepper were studied. The rehydration ratio decreased with temperature and the maximum water holding capacity was achieved at 50 °C. Both vitamin C content and the total phenolic content decreased as air-drying temperature decreased. The radical scavenging activity showed higher antioxidant activity at high temperatures (i.e. 80 and 90 °C) rather than at low temperatures (i.e. 50, 60 and 70 °C). Chromatic parameters (L*, a*, b*, C* and H°), non-enzymatic browning compounds and extractable colour were affected by drying temperature, which contributed to the discolouring of pepper during this process.
Article
Phenolic compounds and antioxidant capacities of bayberry juices from 14 cultivars were investigated. HPLC–DAD and Folin-Ciocalteu methods were used for the analysis of the phenolic compounds. Biqi had the highest content of total flavonols (56.75 ± 4.68 mg/l), Wuzi had the highest content of phenolic acids (30.1 ± 0.05 mg/l), and Lizhizhong had the highest content of anthocyanins (514 ± 46.1 mg/l) and total phenolics (1055 ± 9.32 mg GAE/l). The FRAP and ABTS+ assay indicated that bayberry juices possessed considerable antioxidant activities, and all the analysed phenolic components contributed to the antioxidant capacities. The results also showed that bayberry juices from red coloured cultivars possessed higher contents of phenolic compounds than those from white coloured cultivars. The higher antioxidant capacities of red bayberry juices implied that they might be potential resources for the development of functional drinks.
Article
This study was conducted to investigate the antioxidant vitamin (vitamin E, vitamin C and β-carotene) content of one of the most important vegetables, tomato, using modern analytical techniques. High-performance liquid chromatographic procedures allowed the separation and quantification of these vitamins as well as their analogues in different cultivars.Carotenoid extract could be fractionated into 14 components, including lycopene, β-carotene and lutein as the major ones. Paired-ion liquid chromatography provided excellent separation of ascorbic acid with high peak purity. In addition to different analogues of tocopherol, ubiquinone-10 could also be separated and sensitively detected by normal-phase chromatography and fluorescence detection.The highest concentrations (3.15–3.98 μg g−1) of total tocopherol (mainly α-analogue) were found in tomato fruits of Katinka, Gitana and Floriset cultivars. The vitamin C content was maximal (36–48 mg per 100 g) in DRW 3126, Primato, Tampo and Monika cultivars. The highest values for β-carotene were found in Monika, Ultimo and Falcato cultivars (3.5–3.9 μg g−1). The dynamics of fruit ripening were also examined.
Article
This study provides new data on the the total carotenoids and β-carotene content of commonly consumed cereals, pulses, vegetables, spices and condiments. Separation of carotenoids by HPLC showed that β-carotene is the predominant carotenoid in all the foods studied. Cereals and pulses appear to be poor sources of provitamin A precursors. Among the vegetables studied pumpkin, ridge gourd, green chillies, tomato, green peas, field beans and French beans are not only inexpensive but are better sources of β-carotene (20–120 mg/100 g). Among the spices and condiments, red chilli (1310 mg/100 g) and Smilax (2136 mg/100 g), which are regularly used in Indian recipes are good sources of provitamin A precursors. The study also identified unconventional sources like Gulmohar, Peltiforum ferruginum,Lucern and Spirulina as rich sources of β-carotene. Considering that Indian diets predominantly consist of cereals and pulses, choosing appropriate combinations of cereals and pulses will contribute significantly to overall vitamin A intakes. Together with our earlier efforts, the present study has generated a database of β-carotene contents of Indian plant foods, which could be of help in the elimination of vitamin A deficiency.
Article
Eight popularly consumed green leafy vegetables in Nigeria namely: Structium sparejanophora, Amarantus cruentus, Telfairia occidentalis, Baselia alba, Solanum macrocarpon, Corchorus olitorus, Vernonia amygdalina, and Ocimum gratissimum were blanched in hot water for 5 mins. The antioxidant properties of the fresh and blanched green leafy vegetables were subsequently determined. The total phenol, ascorbic acid and the antioxidant potentials as typified by reducing property and free radical scavenging activity was also determined. The results of the study revealed that blanching cause a significant (P<0.05) increase in the total phenol [fresh (0.1–0.3 g/100 g), blanched (0.2–0.6 g/100 g)] content of the green leafy vegetables except in Amarantus cruentus and Vernonia amygdalina where there was no change. Conversely, there was a significant (P<0.05) decrease in the vitamin C [fresh (43.5–148.0 mg/100 g), blanched (15.8–27.3 mg/100 g)], reducing property [fresh (0.5–1.5 absorbance), blanched (0.1–0.6 absorbance)] and free radical scavenging ability [fresh (20.0–51.4%), blanched (16.4–47.1%)] of the blanched green leafy vegetables except in Structium sparejanophora, where there was no change in the reducing property (0.6 absorbance) and free radical scavenging ability (59.8%) of the blanched vegetable. In view of this it could be concluded that blanching of vegetables though makes green leafy vegetables more palatable and less toxic, however it reduces their antioxidant properties drastically.
Article
Dry beans are rich sources of dietary fiber and phytochemicals such as flavonoids and phenolics. In the current study, we determined the effects of two processing methods (soaking and toasting) on total phenolics, flavonoids, proanthocyanidin and antioxidant potential by 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity and ferric reducing antioxidant potential (FRAP) in selected dry beans (red kidney beans (K), black-eyed peas (B), pinto beans (P) and soy beans (S)).Total phenolics (mg/g dwb) expressed as gallic acid equivalents (GAE), total flavonoids (mg/g dwb) as catechin equivalents (CE) and proanthocyanidin expressed as leucocyanidin equivalent (mg LE/g) ranged from 3.42 to 7.21, 0.61 to 0.84 and 0.51 to 3.13 in raw beans; 3.58 to 6.94, 0.19 to 0.99 and 0.43 to 3.13 in soaked beans and 4.55 to 9.52, 0.23 to1.00 and 0.20 to 3.25 in toasted beans, respectively.FRAP (μg/g) in raw, soaked and toasted dry beans ranged from 0.00097 to 0.00424 while DPPH(T30) (%) ranged from 43.9 to 62.61.Our results indicate that processing methods (soaking and roasting) influenced total phenolic, flavonoid and antioxidant contents (DPPH, FRAP) in selected dry beans.
Article
Polyphenols constitute one of the most numerous and ubiquitous groups of plant metabolites and are an integral part of both human and animal diets. Ranging from simple phenolic molecules to highly polymerized compounds with molecular weights of greater than 30,000 Da, the occurrence of this complex group of substances in plant foods is extremely variable. Polyphenols traditionally have been considered antinutrients by animal nutritionists, because of the adverse effect of tannins, one type of polyphenol, on protein digestibility. However, recent interest in food phenolics has increased greatly, owing to their antioxidant capacity (free radical scavenging and metal chelating activities) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Much of the literature refers to a single group of plant phenolics, the flavonoids. This review offers an overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, as well as a brief description of the chemistry of polyphenols and their occurrence in plant foods.
Article
This study aimed at evaluating the antioxidative activity of crude hsian-tsao leaf gum extracted by sodium bicarbonate solutions and precipitated by 70% ethanol. The antioxidative activities, including the radical-scavenging effects, Fe(2+)-chelating ability, and reducing power as well as the inhibition of FeSO(4)-H(2)O(2)-induced malondialdehyde formation in rat tissue homogenate were studied in vitro. It was found that the antioxidative effect provided by hsian-tsao leaf gum was strongly concentration dependent. In general, the antioxidative activity increased with increasing gum concentration, to a certain extent, and then leveled off with further increase in gum concentration. A concentrtaion-dependent kinetics for the rate of change in antioxidative activity was proposed. The antioxidative activity constant (k) and the half-inhibition concentration (IC(50)) for each antioxidative reaction studied were calculated. From a comparison of the IC(50) values for different antioxidative reactions, it seemed that hsian-tsao leaf gum was more effective in scavenging superoxide radicals than chelating Fe(2+) or scavenging alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radicals. As compared to the commercial antioxidants, hsian-tsao leaf gum showed less scavenging effect on the DPPH radical and reducing power but better superoxide radical-scavenging effect and Fe(2+)-chelating ability than alpha-tocopherol and BHT.
Article
Fourteen tropical fruits from south Florida (red guava, white guava, carambola, red pitaya (red dragon), white pitaya (white dragon), mamey sapote, sapodilla, lychee, longan, green mango, ripe mango, green papaya, and ripe papaya) were evaluated for antioxidant activity, total soluble phenolics (TSP), total ascorbic acid (TAA), total dietary fiber (TDF), and pectin. ORAC (oxygen radical absorbance capacity) and DPPH (1,1-diphenyl-2-picrylhydrazyl, radical scavenging activity) assays were used to determine antioxidant activity. The TSP, ORAC, and DPPH ranged from 205.4 to 2316.7 g gallic acid equiv/g puree, <0.1 to 16.7 micromol Trolox equiv/g puree, and 2.1 to 620.2 microg gallic acid equiv/g puree, respectively. The TAA, TDF, and pectin ranged from 7.5 to 188.8 mg/100 g, 0.9 to 7.2 g/100 g, and 0.20 to 1.04 g/100 g, respectively. The antioxidant activities, TSP, TAA, TDF, and pectin were influenced by cultivar (papaya, guava, and dragon fruit) and ripening stage (papaya and/or mango). Antioxidant activity showed high correlations with levels of TSP compounds (r = 0.96) but low correlations with levels of ascorbic acid (r = 0.35 and 0.23 for ORAC and DPPH data, respectively). The antioxidant activities evaluated by both ORAC and DPPH showed similar trends where red guava and carambola exhibited the highest and sapodilla and green papaya exhibited the lowest levels. Guava and mamey sapote exhibited the highest TDF and pectin levels. Many of the tropical fruits were shown to contain an abundance of hydrolyzable tannins, ellagic acid conjugates, and flavone glycosides. Preliminary descriptions are given of the phenols in red/white pitaya (dragonfruit), lychee, and mamey sapote, these fruit being thus far uncharacterized in the literature.
Antioxidant activity and phenolic content of raw and blanched Amaranthus species Effect of processing on antioxidant contents in selected dry beans Polyphenols: Chemistry, dietary sources, metabolism and nutritional significance
  • I Amin
  • Y Norazaidah
  • K I Hainida
  • J Boateng
  • M Verghese
  • L T Walker
  • S Ogutu
Amin, I., Norazaidah, Y., & Emmy Hainida, K. I. (2006). Antioxidant activity and phenolic content of raw and blanched Amaranthus species. Food Chemistry, 94, 47−52. Boateng, J., Verghese, M., Walker, L. T., & Ogutu, S. (2008). Effect of processing on antioxidant contents in selected dry beans (Phaseolus spp. L.). LWT—Food Science and Technology, 41, 1541−1547. Bravo, L. (1998). Polyphenols: Chemistry, dietary sources, metabolism and nutritional significance. Nutrition Reviews, 56, 317−333. Cerretani, L., Bendini, A., Rodriguez-Estrada, M. T., Vittadini, E., & Chiavaro, E. (2009).
The effect of cooking methods on total phenolics and antioxidant activity of selected green vegetables. Food Chemistry, 93, 713−718 Effect of air-drying temperature on physico-chemical properties, antioxidant capacity, colour and total phenolic content of red pepper
  • N Turkmen
  • Sari
  • Y S Velioglu
  • A Vega-Galvez
  • K D Scala
  • K Rodríguez
  • R Lemus-Mondaca
  • M Miranda
  • J Lopez
Turkmen, N., Sari, & Velioglu, Y. S. (2005). The effect of cooking methods on total phenolics and antioxidant activity of selected green vegetables. Food Chemistry, 93, 713−718. Vega-Galvez, A., Scala, K. D., Rodríguez, K., Lemus-Mondaca, R., Miranda, M., Lopez, J., et al. (2009). Effect of air-drying temperature on physico-chemical properties, antioxidant capacity, colour and total phenolic content of red pepper (Capsicum annuum, L. var. Hungarian). Food Chemistry, 117, 647−653.
Carotene content of some common (cereals, pulses, vegetables, spices and condiments) and unconventional sources of plant origin Studies on the antioxidant activities of hsian-tsao (Mesona procubens Hemls) leaf gum Total antioxidant activity and fiber content of select Florida-grown tropical fruits
  • B Kandlakunta
  • A Rajendran
  • L Thingnganing
  • L S Lai
  • S T Chou
  • W W Chao
  • G Luzio
  • S T Talcott
  • K Goodner
  • E A Baldwin
Kandlakunta, B., Rajendran, A., & Thingnganing, L. (2008). Carotene content of some common (cereals, pulses, vegetables, spices and condiments) and unconventional sources of plant origin. Food Chemistry, 106, 85−89. Lai, L. S., Chou, S. T., & Chao, W. W. (2001). Studies on the antioxidant activities of hsian-tsao (Mesona procubens Hemls) leaf gum. Journal of Agricultural and Food Chemistry, 49, 963−968. Mahattanatawee, K., Manthey, J. A., Luzio, G., Talcott, S. T., Goodner, K., & Baldwin, E. A. (2006). Total antioxidant activity and fiber content of select Florida-grown tropical fruits. Journal of Agricultural and Food Chemistry, 54, 7355−7363.
Predicting the bioavailability of antioxidants in food: Antioxidants in foods: Practical applications
  • S Southon
  • R Faulks
Southon, S., & Faulks, R. (2001). Predicting the bioavailability of antioxidants in food: Antioxidants in foods: Practical applications. Abington Cambridge, England: Wood-head Publication Limited.
Total phenolic contents and antioxidant activity of corn tassel extracts Effect of blanching on the antioxidant properties of some tropical green leafy vegetables
  • S M Mohsen
  • A S M Ammar
Mohsen, S. M., & Ammar, A. S. M. (2009). Total phenolic contents and antioxidant activity of corn tassel extracts. Food Chemistry, 112, 595−598. Oboh, G. (2005). Effect of blanching on the antioxidant properties of some tropical green leafy vegetables. Swiss Society of Food Science and Technology, 38, 513−517.
Development and evaluation of an HPLC method for the analysis of carotenoids in foods, and the measurement of the carotenoid content of vegetables and fruits commonly consumed in the UK
  • Hart