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Effect of Different Cooking Methods on Vegetable Oxalate Content
Abstract
Approximately 75% of all kidney stones are composed primarily of calcium oxalate, and hyperoxaluria is a primary risk factor for this disorder. Nine types of raw and cooked vegetables were analyzed for oxalate using an enzymatic method. There was a high proportion of water-soluble oxalate in most of the tested raw vegetables. Boiling markedly reduced soluble oxalate content by 30-87% and was more effective than steaming (5-53%) and baking (used only for potatoes, no oxalate loss). An assessment of the oxalate content of cooking water used for boiling and steaming revealed an approximately 100% recovery of oxalate losses. The losses of insoluble oxalate during cooking varied greatly, ranging from 0 to 74%. Because soluble sources of oxalate appear to be better absorbed than insoluble sources, employing cooking methods that significantly reduce soluble oxalate may be an effective strategy for decreasing oxaluria in individuals predisposed to the development of kidney stones.
... O oxalato, frequentemente encontrado em vegetais, não pode ser metabolizado pelos humanos e é excretado na urina. Segundo Chai & Liebman [23] , cerca de 75% de todos os cálculos renais são compostos, principalmente, de oxalato de cálcio e a hiperoxalúria é um dos principais fatores de risco para esta doença porque o oxalato origina de uma combinação de absorção de oxalato da dieta e sintetizados endogenamente. A restrição da ingestão de oxalato na dieta tem sido sugerida como um tratamento para prevenir a nefrolitíase recorrente em alguns pacientes. ...
... Sabe-se que o tratamento térmico, dentre outras funções, é um método bastante utilizado para redução e/ ou inativação de substâncias indesejáveis em alimentos. Desse modo, vários estudos [17,23,45,46] têm sido realizados para avaliar o efeito da temperatura nos teores dos fatores antinutricionais em produtos alimentícios. [17] estudaram o efeito da extrusão na biodisponibilidade do cálcio e de fatores antinutricionais em sementes de amaranto. ...
... Chai & Liebman [23] avaliaram o efeito de diferentes métodos de cozimento em vegetais no conteúdo de oxalato e observaram que a fervura promoveu uma maior redução no teor de oxalato (30-87%) e foi mais eficaz do que cozinhar (5-53%) e do que o forneamento (usado apenas para a batata, sem perda de oxalato). Os autores afirmam que o emprego de métodos de cozimento reduzem significativamente o oxalato e pode ser uma estratégia eficaz para diminuir oxalúria em indivíduos com predisposição para o desenvolvimento de pedras nos rins. ...
Os alimentos, além de apresentarem substâncias nutritivas essenciais para o desenvolvimento do organismo, podem também conter uma variedade de fatores antinutricionais, como os inibidores de proteínas, oxalatos, taninos, nitritos, dentre outros, assim denominados, devido ao fato de interferirem na absorção de nutrientes, podendo acarretar danos à saúde quando ingeridos em altas quantidades. Assim, esse artigo tem como objetivo discutir as possíveis consequências dos fatores antinutricionais em alimentos, assim como os efeitos do processamento sobre essas substâncias e apresentar estudos biológicos sobre os mesmos.
... (1) Vegetable samples: according to the previous literature (Chai & Liebman, 2005), the procedures of sample preparation were as follows (Scheme 1a): ...
... A linear range of 0.1-6 μmol mL − 1 was obtained, its linear correlation coefficient (R 2 ) was 0.9990. According to the literatures (Chai & Liebman, 2005;Siener, Seidler, Voss, & Hesse, 2017), the oxalate concentrations in vast majority of the samples were within this linear range, meeting the demand for daily analysis. Besides, as above-mentioned, Mn 2+ can be served as a catalyst to accelerate the reaction rate, the addition of Mn 2+ can shorten the reaction time. ...
A gas pressure meter-based portable/miniaturized analytical kit was established for rapid and on-site detection of oxalate. Potassium permanganate (KMnO4) and oxalate solution were mixed together in bottle-in-bottle reaction device, a simple oxidation reaction process occurred within 6 min and carbon dioxide (CO2) was generated, inducing the pressure of the sealed bottle changed, which was measured by a portable gas pressure meter. A detectable range of 0.1–6 μmol mL⁻¹ and a detection limit of 0.064 μmol mL⁻¹ were achieved. The proposed analytical method was further used for the analysis of several real samples (spinach, beverages and water samples), with the recoveries of 89–111%. Considering the interferences from the complicated matrix, calcium chloride (CaCl2) was served as a precipitant, oxalate (C2O4²⁻) was precipitated with Ca²⁺ to form precipitation (CaC2O4), CaC2O4 was then separated from the matrix by centrifuge/filter, eliminating the interferences. It is a rapid, easy-used and interference-free analytical system/device for oxalate on-site and real time analysis.
... In the use of foods of plant origin, the identification of compounds considered as "antinutrients" must also be considered due to their adverse effects. One of these compounds is oxalate, which is present in chaya [37][38][39]. Excessive consumption of oxalates is contraindicated due to their ability to generate insoluble complexes with minerals such as calcium (Ca 2+ ), iron (Fe 2+ ), and magnesium (Mg 2+ ) by promoting their accumulation [38]. In this sense, many strategies such as soaking, steaming, boiling, or cooking have been reported to reduce the oxalate concentration from foods. ...
... Our results showed a significant decrease in the oxalate content in the different formulations of cookies in comparison with the chaya flour, indicating that the baking temperature has an important role in decreasing this antinutritional component. Similar results reported a decrease of 30% and 87% in the total oxalate content of boiling vegetables compared with that of baked or steamed vegetables [39]. ...
Chaya and amaranth are Mexican traditional foods with a high nutritional value. Many studies have demonstrated the individual beneficial effect of each. However, there is no evidence of the use of these foods on the formulation of functional foods. This study evaluated the effect of replacing 5–20% of wheat flour with chaya and amaranth flours to generate four different formulations of cookies. Proximal analysis, total polyphenols and oxalate content, antioxidant activity, fatty acid profile, and sensory analysis were performed on the cookies. The results of the chemical composition showed that all cookies have a high protein content (9.21–10.10%), an adequate amount of fiber (5.34–6.63%), and a balanced ratio of unsaturated–saturated fatty acids (70:20), and they contain PUFAs (50.4–53.2 g/100 g of fatty acids), especially α-linolenic and oleic acids. All formulations presented antioxidant activity (2540 ± 65.9 to 4867 ± 61.7 Trolox equivalents (μmoles/100 g)) and polyphenols (328–790 mg/100 g); in particular, quercetin was identified in their composition. Results of the sensory analysis indicated that incorporation of chaya and amaranth flour in cookies does not affect the acceptability of the products. The inclusion of traditional foods, such as chaya and amaranth, in cookies enhances their nutritional value and increases the content of bioactive compounds associated with health effects.
... Traditionally, dietary oxalate intake has been associated with the pathophysiology of kidney stone disease risk (Crivelli et al., 2021), and a relationship between dietary oxalates and kidney stone formation has been observed in human studies (Curhan, Willett, Knight & Stampfer, 2004). In relation to oxalate content, it is important to take into consideration that soluble oxalates have a greater impact on bioavailability and the risk of stone formation than insoluble oxalate (Chai & Liebman, 2005). Thus spinaches contain an average of 1145 mg total oxalate/100 g fresh weight, with 803 mg being soluble oxalate (Petroski & Minich, 2020). ...
... A boiling process for 12 min resulted in a reduction between 30% and 87% of soluble oxalates. Whereas, in steam cooking the reduction in oxalates is around 42% to 46% (Chai & Liebman, 2005). Similarly, with soaking a loss of oxalate content between 40.5% and 76.9%, can be achieved (Akhtar, Israr, Bhatty & Ali, 2011). ...
The intake of foods derived from plants has been proposed as an useful strategy in the prevention of several chronic diseases. However, plants also possess a group of substances known as antinutrients, which may be responsible for deleterious effects related to the absorption of nutrients and micronutrients, or exert beneficial health effects. This review compiles scientific evidence regarding the physiological impact of some antinutrients (lectins, goitrogens, phytates and oxalates) in the human health, their negative effects and the culinary and industrial procedures to reduce their presence in foods. It can be concluded that, the effects of antinutrients on human health could change when consumed in their natural food matrix, and after processing or culinary treatment. Accordingly, some of these compounds could have beneficial effects in different pathological conditions. Future research is required to understand the therapeutic potential of these compounds in humans.
... These findings contrast with higher values reported by Olatunde et al. [24] and Adane et al. [25], who noted oxalate levels up to 243.06% in raw taro. Variations in oxalate levels may result from differences in plant parts, species, and growth conditions [26]. Processing methods like fermentation have been shown to reduce oxalate content, as indicated by Igbabul et al. [19]. ...
This study investigated the proximate composition, phytochemical content, and amino acid profiles of cocoyam (Colocasia esculenta) tuber and leaves. Proximate analysis revealed that the samples contained 16.63% crude protein, 3.19% fat, 8.38% ash, 6.37% crude fiber, 6.51% moisture, and 58.94% carbohydrate on average. Phytochemical screening identified the presence of oxalates, saponins, alkaloids, flavonoids, tannins, and cyanide in varying concentrations. Amino acid profiling showed that the samples contained all essential amino acids with leucine (6.99%), lysine (4.46%), and isoleucine (4.21%) being the most abundant. Glutamic acid (10.29%) and aspartic acid (8.87%) were the predominant non-essential amino acids. The total amino acid content ranged from 54.84 to 74.85 g/100g protein. Essential amino acid scores indicated that most amino acids met or exceeded FAO/WHO reference values, with phenylalanine + tyrosine having the highest score. The study reveals that cocoyam tubers are excellent sources of energy, while the leaves are significantly higher in protein and essential amino acids than other widely consumed leaves, highlighting its potential as some nutrient-dense food source rich in essential amino acids and carbohydrates.
... This decrease in oxalate levels highlights the potential impact of freezing storage on the nutritional quality of peas. Further research and analysis could provide valuable insights into the mechanisms behind this reduction and its implications for the nutritional value and safety of peas during freezing storage as reported by Chai et al. (2005). The data from Figure (5) for green peas during freezing over six months at approximately -20°C indicates a negative correlation between nitrite and nitrate, as well as nitrite and oxalate. ...
This study investigates the effect of the blanching, refrigeration, and freezing on nitrate, nitrite, and oxalate levels in green beans and peas. Besides, the impact of these preservation methods on the nutritional and safety aspects of these vegetables was studied. The data revealed that the refrigeration significantly impacts nitrate levels in both green beans and peas, potentially due to biochemical and metabolic processes. Furthermore, there was a notable decrease in nitrate content from 2121.17 mg.kg-1 to 1371.74 mg.kg-1 in green beans after blanching and six months of freezing storage. This reduction in nitrate levels is attributed to both blanching and freezing storage, potentially influenced by enzymatic activities and chemical reactions. The study also observed a decline in oxalate levels, suggesting that blanching and freezing storage contribute to reduced oxalate content, likely influenced by enzymatic and chemical reactions. These findings align with previous research indicating significant reductions in nitrates, nitrites, and oxalates due to blanching, particularly for leafy vegetables, reinforcing the observed trends during freezing storage. In essence, the cold storage, blanching, and freezing processes led to reduced levels of nitrate, nitrite, and oxalates in green beans and peas.
... Evidence from the study by Miller and colleagues was concorded with the EPIC study, where raw vegetable intake was inversely associated with mortality, in particular, cardiovascular mortality [27]. Cooked vegetables alter the nutrients' bioavailability (i.e., phytochemicals, vitamins, minerals, and fiber), structure, digestibility, and destruction of the digestive enzymes, which may affect the health outcomes of the consumers [36,37]. Nevertheless, although the mode of preparation of the FVs was not examined in the present study, cooked vegetables are commonly presented on dining tables, albeit Malaysia is known for cultural diversity. ...
Background/Objective: We investigated the relationship between daily adequate FV intake and risk of all-cause, cardiovascular disease (CVD), and cancer mortalities among Malaysian adults. Methods: Data from a total of 18,211 Malaysian adults aged 18 years and above whom participated in the National Health and Morbidity Survey 2011 were analyzed. The participants were followed up for approximately 11 years, and mortality data were ascertained through record linkages with the death registry from the Malaysian National Registration Department. Multiple Cox regression was applied to assess the association between daily adequate FV intake and risk of all-cause, CVD, and cancer mortalities, adjusting for sociodemographic, lifestyle, and health conditions. Results: During the follow-up period, we observed a total of 1809 all-cause, 374 CVD, and 216 cancer mortalities. No significant association between daily adequate FV intake with all-cause mortality (adjusted hazard ratio (aHR): 1.01, 95% confidence interval (CI: 0.79–1.31), CVD mortality (aHR: 0.91, 95% CI: 0.57–1.47), and cancer mortality (aHR: 1.27, 95% CI: 0.74–2.17) were observed, even after excluding deaths that occurred in the first two years of observation. Conclusions: Further investigation on the type of FV intake and its preparation method with risk of mortality will provide a holistic insight into the causal relationship between FV intake and mortality.
... 32 Oxalates, present in high amounts in spinach, are similar to phytates in that they inhibit calcium absorption, but cooking methods such as boiling help reduce them. 33 Previous studies show that teff is more often consumed by urban than rural populations due to its availability and increasing price. 25,34 Its consumption is low in Somali, SNNPR, Gambella, Benishangul-Gumuz, and western Oromia regions. 1 The price of teff is higher than other grains; however, monitoring of teff's food value chain is limited. ...
Increasing dietary calcium intakes of Ethiopian women of reproductive age (WRA) is a public health priority for reducing pre‐eclampsia in pregnancy. Using linear programming, we determined whether locally available foods consumed by WRA in nine regions (urban and rural) and two administrative cities of Ethiopia could provide 1000 mg/day of dietary calcium, and we identified food‐based recommendations (FBRs) to improve dietary calcium adequacy in each region. Results showed that diets providing 1000 mg/day of calcium were feasible in eight regions (40%) of the target populations examined. It would, however, require marked changes for most populations (90%), increasing the number of servings per week of several food groups to levels close to those of high consumers in each population. The selected calcium‐specific FBRs integrate well into the 2022 Ethiopian Dietary Guidelines, requiring additional messages to consume green leafy vegetables, milk, root crops, or teff (Eragrostis tef) or to consume a higher number of servings of vegetables than currently recommended, depending on the population. In conclusion, these analyses show that a food‐based approach can be used to achieve dietary calcium adequacy among WRA in 40% of the populations examined. For the other populations, food‐based interventions alone may be inadequate and other interventions are likely needed.
... Oxalate can have deleterious effects on human nutrition and health, particularly by decreasing calcium absorption and aiding the formation of kidney stones (Noonan and Savage, 1999). Cooking has been found effective in the reduction of oxalate content in oil seeds (Chai and Liebman, 2005). A decrease in the oxalate content was observed in both cooked samples. ...
This study examined the impact of cooking, Co-60 gamma irradiation (5 kGy and 10 kGy) and combined irradiation (10 kGy) and cooking treatments on the amino acid profile and physicochemical properties of African locust bean (Parkia biglobosa) seeds, as well as the quality of the seed oil. The treated and untreated (control) seeds were mechanically dehulled and milled into flour using an attrition mill, and subsequently analysed for chemical composition, amino acid profile, functional properties and quality of the seed oil. The results showed a significant increase in the fat content (p ≤ 0.05) after cooking and post-irradiation cooking treatments. The cooked seed samples recorded a 3.84% increase in total mineral content although there was a loss in the total percentage minerals after combined irradiation and cooking which could be linked to leaching of soluble minerals into cooking water. The 10 kGy irradiation dose improved the total essential amino acids present in the seed possibly due to the lyses of adherrent microflora. Percentage cysteine was highest in the 5 kGy irradiated seed sample with about 4.8% increase compared to control. There was a 92.6% loss in foaming capacity of the seed flour as a result of processing; however, 5 kGy irradiated sample recorded only about 26% loss in the foaming capacity. The anti-nutrients were significantly reduced by cooking, irradiation, post-irradiation cooking up to about 60%, 40%, 26.7% and 60% for cooked, 5 kGy irradiated, 10 kGy irradiated and post-irradiated cooked samples, respectively. Tannin content was not significantly affected (p<0.05) by the irradiation treatments; it was however reduced significantly by post-irradiation cooking. The 5 kGy and 10 kGy doses did not significantly affect iodine value of the oil sample. There was however an increase in iodine value as a result of cooking and post-irradiation cooking with values as high as 163.53 g I2 and 182.77 g I2 per 100g, respectively. Overall, it could be concluded that medium dose gamma irradiation did not negatively affect the quality of the African locust bean seed, which is desirable for elongation of storage life of the seed.
... Antinutrients can have positive effects in food but often negatively impact metabolic performance. Antinutritional factors in staple crops can reduce the efficiency of protein digestibility and nutrients absorption (Table 1) [27][28][29][30][31][32]. For example, trypsin inhibitors in legumes and grains act as a defense mechanism against insects and other pests though decrease protein digestibility (50%) when ingested by humans, although trypsin inhibitors may be inactivated through minimal processing [27,[33][34][35]. ...
Protein inadequacy is a major contributor to nutritional deficiencies and adverse health outcomes of populations in low- and middle-income countries (LMICs). People in LMICs often consume a diet predominantly based on staple crops, such as cereals or starches, and derive most of their daily protein intakes from these sources. However, plant-based sources of protein often contain low levels of indispensable amino acids (IAAs). Inadequate intake of IAA in comparison with daily requirements is a limiting factor that results in protein deficiency, consequently in the long-term stunting and wasting. In addition, plant-based sources contain factors such as antinutrients that can diminish protein digestion and absorption. This review describes factors that affect protein quality, reviews dietary patterns of populations in LMICs and discusses traditional and novel small- and large-scale techniques that can improve the quality of plant protein sources for enhanced protein bioavailability and digestibility as an approach to tackle malnutrition in LMICs. The more accessible small-scale food-processing techniques that can be implemented at home in LMICs include soaking, cooking, and germination, whereas many large-scale techniques must be implemented on an industrial level such as autoclaving and extrusion. Limitations and considerations to implement those techniques locally in LMICs are discussed. For instance, at-home processing techniques can cause loss of nutrients and contamination, whereas limitations with larger scale techniques include high energy requirements, costs, and safety considerations. This review suggests that combining these small- and large-scale approaches could improve the quality of local sources of proteins, and thereby address adverse health outcomes, particularly in vulnerable population groups such as children, adolescents, elderly, and pregnant and lactating women.
... As for nitrate, soluble oxalate is leached into cooking water and this reduces its content in the eaten leaves (Savage and Klunklin, 2018). For instance, boiling reduced by 85% the content of soluble oxalate in Swiss chard leaves (Chai and Liebman, 2005). Also, appropriate modification of the hydroponic growing technique could reduce leaf oxalate concentration at harvest. ...
... This indicates that the forming process consisting of wet heat treatment followed by heating compression could reduce the soluble oxalate. This result agrees with the reports of Chai and Liebman [55] and Bong et al. [56] revealing that soluble oxalate was easily eliminated during heating, especially boiling and steaming. Because the soluble oxalate could be dissolved in water and eliminated with the water vapor, no significant differences of oxalate reduction in all KF/ MCC specimens were found (Table 4). ...
Common konjac flour, especially of low grade, is a waste material produced in large quantities during purification of konjac glucomannan (KGM). It contains impurities, particularly oxalate salts, which irritate and may cause kidney stones. Konjac flour has glucomannan as a main component. Glucomannan is characterized by low crystallinity, high thermostability, and the ability to form a strong gel. Subsequently, glucomannan has good potential for the production of biodegradable material. However, its high-water affinity limits its use in packaging. The deacetylated by thermal forming process and reinforced konjac flour with 15% and 20% of microcrystalline cellulose showed improved water absorption and thermal properties of the specimen. Moreover, the thermal forming process resulted in the reduction of soluble oxalate. Therefore, due to the conditions used in this experiment, the material will be stronger, more waterproof properties, and more highly resistant to temperatures, so it is suitable to be used as a packaging that is environmentally friendly.
... alba, and Astraeus hygrometricus to reduce their bitterness and to enhance softness. Hot water treatment and boiling are the best possible pre-cooking methods for reducing soluble oxalate content and pyrrolizidine alkaloids in some wild leafy vegetables and underground parts (Chai and Liebman, 2005;Savage and Dubois, 2006;Hajšlová et al., 2018;Takenaka et al., 2022). Local tribes of eastern India followed this method for processing the leaves and petioles of Colocasia esculenta, leaves of Typhonium trilobatum, tuber of Dioscorea spp., and corm of Amorphophallus sylvaticus. ...
Background
Inventorization and promotion of traditionally used local flora can be a better option to gain a wide range of alternative edible resources and multiple nutritional benefits. A perusal of literature highlighted the poor nutritional status of the tribal community living in eastern India and pointed out the potential lack of information regarding locally available wild edible resources.
Objective
Present study aimed to document detailed information on wild edibles of eastern India, evaluate their cultural significance, and understand their role in achieving food security for the local tribes.
Materials and methodology
Traditional knowledge of wild edibles was collected using a semi-structured questionnaire. Standard protocols were followed for collecting data. The collected data were analyzed using specific statistical tools like Relative frequency of citation (RFC), and Cultural food significance index (CFSI) to identify the most cited and culturally significant species. Jaccard similarity index (JI) was used to check the similarity of food plant use in different localities and adjoining areas of the laterite region in eastern India.
Results
A total of 2,603 citations were made by the 153 participants for 83 types of wild edibles spread across 48 families. Among the 83 species, 65 species were angiosperms, three species were pteridophytes and the rest 15 were from fungal groups. The RFC value ranged from 0.04 to 0.76, and Madhuca longifolia (L.) J.F.Macbr. was identified as the most frequently cited species (FC = 116; RFC = 0.76). The Cultural food significance index (CFSI) value varied from 0.2 to 844, and thirteen wild edibles like Colocasia esculenta (L.) Schott, Enydra fluctuans Lour., Marsilea vestita Hook. & Grev., Termitomyces heimii Natarajan, etc. were identified as culturally most important in the locality.
Conclusion
Present study concludes that the local flora and macrofungi diversity is a treasure trove for fulfilling human hunger and gaining enough nutritional benefit. Scientific and sustainable utilization of these wild edibles can be a wise step to attain multiple health benefits and food security for the tribal community of eastern India. Moreover, culturally accepted species can be opted as a good source for bioprospecting nutraceuticals.
... According to the literature, various methods have been employed for the determination of oxalate in foods, including enzymatic assays [4][5][6][7][8][9][10][11], spectrofluorimetry [12], spectrophotometry, amperometry [9,13,14], electrochemical [15,16], capillary electrophoresis [17,18], titration [19][20][21][22][23][24][25][26][27], gas chromatography (GC) [28], and high-performance liquid chromatography (HPLC). HPLC is the most recently referenced method used for the determination of oxalates because of its high sensitivity, accuracy, versatility, and reliability, despite being expensive to purchase, repair, and maintain [29]. ...
Oxalate is an antinutrient present in a wide range of foods, with plant products, especially green leafy vegetables, being the main sources of dietary oxalates. This compound has been largely associated with hyperoxaluria, kidney stone formation, and, in more severe cases, systematic oxalosis. Due to its impact on human health, it is extremely important to control the amount of oxalate present in foods, particularly for patients with kidney stone issues. In this review, a summary and discussion of the current knowledge on oxalate analysis, its extraction conditions, specific features of analytical methods, reported occurrence in foods, and its health implications are presented. In addition, a brief conclusion and further perspectives on whether high-oxalate foods are truly problematic and can be seen as health threats are shown.
... Oxalates could also affect mineral absorption, mostly calcium. Chai and Liebman [100] reported a wide range (from 4 to 80 mg/100 g) of oxalate levels in cooked dry bean samples, among which green and yellow split peas, as well as black-eyed peas, contain relatively lower oxalate concentrations. ...
... Although vegetables have been reported to one of the main calcium sources in Japan ( Ministry of Health, Labour and Welfare in Japan 2019 ) , the absorption rate of vegetables is not good due to the presence of oxalic acid. They are not considered as a good source of calcium ( Ogawa et al. 1994 ;Chai and Liebman 2005 ) . It has been reported that vinegar or mayonnaise increases the absorption of calcium ( Ji et al. 2019 ) . ...
This study aims to confirm the "vegetable-first" effect. In addition, because we aimed dietary fiber in vegetable salad, the effect after the ingestion of vegetable salad extract (vegetable salad from which solids have been removed) before carbohydrates on postprandial serum glucose level was also evaluated. Thirteen healthy men were given meals after one-night fasting: rice-vegetable salad, vegetable salad-rice, and vegetable salad extract-rice. Blood samples were taken at 0, 30, 45, 60, 90, and 120 min after the ingestion of the test meal to measure serum glucose levels. Serum glucose level was significantly lower after 45 and 60 min in the vegetable salad-rice group compared to the rice-vegetable salad group. No significant difference was found between the vegetable salad extract-rice group and the vegetable salad-rice/rice-vegetable salad group. The result suggested that it might be important to ingest vegetables to obtain the "vegetable-first" effect.
... However, the management of the domestication and the fertilization (by manure in the present experiment) might be useful to decrease the content of oxalates in S. minor edible parts. Boiling, steaming, or other cooking technologies could also be very useful to reduce oxalic acid content since it is well known that this organic acid is very sensitive to high temperatures [24]. ...
Sanguisorba minor Scop. is a wild edible species distributed in the Mediterranean area and present in numerous traditional food recipes. In the present study, the assessment of nutritional value (ash, carbohydrates, fat, proteins, energy, free sugars, organic acids, tocopherols, fatty acid composition, and minerals) of wild and domesticated S. minor plants was performed. Results showed an increase in ash, protein, fat, organic acid, and α-tocopherol content after the plant’s domestication. Retention of free sugars, especially sucrose, was observed from wild plants to domesticated ones. However, the cultivated plants reported a higher content of polyunsaturated fatty acids than saturated molecules, and both wild collection and domestication maintained a low ω6/ω3 ratio, confirming the role of this species in the prevention of oxidative and inflammatory processes. This aspect is also suggested by the high α-tocopherol content, a vitamin known for its ability to scavenge free-radical species. Nevertheless, a high oxalic acid content was found in domesticated plants. However, the management of fertilization in open field cultivation can be robust in terms of organic acid and mineral (e.g., calcium) content. Indeed, the most representative macrominerals found in domesticated plants were Ca and Mg. The present study suggests a possible introduction of S. minor species in the human diet as a functional food or ingredient by virtue of its high nutritional properties and contents. Moreover, the management of fertilization and domestication might be a solution to maintain/enhance the nutritional profile of this wild species.
... According to García-Herrera and Sánchez-Mata (2016), green leafy vegetables (i.e., such as some Rumex spp., S. vulgaris, and some Taraxacum spp.) should be avoided by people who suffer from kidney stones and other renal disorders despite their high content in Ca, due to the presence of high concentrations of this organic acid, and the preferable oxalic acid/Ca ratio in plant foods should be lower than 2.5 [60]. Furthermore, food processing, such as cooking, might alter, either by increasing or reducing, the influence of these anti-nutritional factors [64,65]. Therefore, ad hoc analyses are currently being planned in order to evaluate this aspect. ...
Background:
Along the Alps, the Alpine diet is considered to be one of the most common nutritional models. Next to traditional animal-based products, spontaneous plants of the territory are collected and eaten.
Aim:
The aim of this study is to evaluate the nutritional features of selected autochthonous plants of the territory and the typical recipe of green gnocchi.
Methods:
The analyses of proximate composition, carotenoid, total phenol, and mineral contents in raw and cooked plant samples and the chemical composition and in vitro starch digestibility in green and control gnocchi were performed.
Results:
Except for Aruncus dioicus, all the wild plants contained high levels of carotenoids (15-20 mg/100 g FW), mainly as xanthophylls. Rumex acetosa showed the highest levels of total phenols (554 mg GAE/100 g FW), and Urtica dioica can be considered to be a good dietary source of iron, calcium, and magnesium (4.9, 410, and 72 mg/100 g FW). Cooking significantly decreased the potassium and magnesium contents in all wild species, and total phenols and carotenoids in Aruncus dioicus, Blitum bonus-henricus, and Silene vulgaris (p < 0.05). The slowly digestible fraction of starch (%SDS/available starch), which is inversely correlated to insulin demand, was significantly increased in green gnocchi compared to matched control gnocchi (p < 0.05).
Conclusions:
Traditional consumption of spontaneous plants in the Alpine regions might increase the dietary intakes of several bioactive substances and contribute to cover the nutritional needs of micronutrients.
... 52 However, carrot has 35.6 mg/100 g of total oxalate, 53 and insoluble oxalate content in carrot reduces with boiling treatment. 24 Therefore, in the present study, the highest oxalic acid content was determined in MYCJ (3.0 g/100 mL) followed by NWCJ (2.1 g/100 mL), however, the lowest oxalic acid contents were in MiOCJ (0.1 g/100 mL) and NOCJ (0.1 g/100 mL). However, a malic acid derivative has been detected in orange carrot juice 38 and purple carrot juice. ...
Background
Carrot is a popular vegetable consumed by people of all age groups and is used in various food products because of its high nutritional content, especially vitamin A.
Results
In the present study, colorful fresh carrot juices of 12 carrot varieties were investigated for in vitro antidiabetic, anti‐aging, and anti‐obesity activities with antioxidant potential by ABTS (2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) and FRAP (ferric reducing ability of plasma) assays. The studied juices were also compared for physicochemical characteristics: titratable acidity, pH, pectin content, total soluble solids, dry mass, ash, viscosity, turbidity, osmolality, and color. The results of the study showed that normal purple carrot juice exhibited the best activities in all biological and antioxidant tests, except for anti‐α‐glucosidase activity. Normal purple carrot juice also had the highest total mineral content with elevated results for titratable acidity, pH, total soluble solids, dry mass, ash, viscosity, and osmolality.
Conclusion
Purple carrot juices demonstrated elevated health‐promoting activities and could be used in blended beverage recipes to attract children's attention. The results of sensorial characteristics (appearance, color, and taste) of juices, however, showed that people are more familiar with orange carrot products. © 2022 Society of Chemical Industry.
... However, no direct evidence has shown that acridity is caused by mechanical puncturing of the skin and several studies suggest that the raphides do not cause acridity (Moy et al., 1979;Paull et al., 1999;Pohl, 1964). Evidence that acridity is due not to the raphides but to a factor on the raphides includes the following: (i) Acridity is lost with cooking and after extraction with methanol, ethanol, distilled water, and water/detergent mixtures with intact raphides remaining (Akpan & Umoh, 2004;Bradbury & Nixon, 1998;Chai & Liebman, 2005;Moy et al., 1979;Payne et al., 1941;Pedler & Warden, 1888;Saha & Hussain, 1983;Tang & Sakai, 1983;Tsai et al., 2006); (ii) there is no strong relationship between acridity and raphide number or amount of calcium oxalate extracted (Halloway et al., 1989;Moy et al., 1979;Payne et al., 1941); (iii) species that have pointed raphides can have very low or no acridity (Bradbury & Nixon, 1998;Ledbetter & Porter, 1970); (iv) the slowness of the acridity response at low concentrations does not suggest mechanical injury; (v) wide variation in sensitivity to taro acridity is not consistent with mechanical penetration; (vi) fewer raphide bundles are often found in the more acrid taro cultivars (Moy et al., 1979); and (vii) treatment of purified acrid raphides with protease leads to rapid loss of acridity with no change in raphide morphology (Paull et al., 1999). An alternate possibility is that chemical irritants or allergens occur on the surface of the raphides (Bradbury & Nixon, 1998;Konno et al., 2014;Nixon, 1987;Paull et al., 1999;Suzuki et al., 1975;Tang & Sakai, 1983), and the raphides play a synergist role as carriers (Konno et al., 2014). ...
Calcium oxalate raphide crystals are found in bundles in intravacuolar membrane chambers of specialized idioblasts cells of most plant families. Aroid raphides are proposed to cause acridity in crops such as taro (Colocasia esculenta (L.) Schott). Acridity is irritation that causes itchiness and pain when raw/insufficiently cooked tissues are eaten. Since raphides do not always cause acridity and since acridity can be inactivated by cooking and/or protease treatment, it is possible that a toxin or allergen‐like compound is associated with the crystals. Using two‐dimensional (2D) gel electrophoresis and mass spectrometry (MS) peptide sequencing of selected peptides from purified raphides and taro apex transcriptome sequencing, we showed the presence on the raphides of peptides normally associated with mitochrondria (ATP synthase), chloroplasts (chaperonin ~60 kDa), cytoplasm (actin, profilin), and vacuole (V‐type ATPase) that indicates a multistage biocrystallation process ending with possible invagination of the tonoplast and addition of mucilage that may be derived from the Golgi. Actin might play a crucial role in the generation of the needle‐like raphides. One of the five raphide profilins genes was highly expressed in the apex and had a 17‐amino acid insert that significantly increased that profilin's antigenic epitope peak. A second profilin had a 2‐amino acid insert and also had a greater B‐cell epitope prediction. Taro profilins showed 83% to 92% similarity to known characterized profilins. Further, commercial allergen test strips for hazelnuts, where profilin is a secondary allergen, have potential for screening in a taro germplasm to reduce acridity and during food processing to avoid overcooking. All edible Aroids cause allergic type responses (acridity) thought to be caused by the sharp calcium oxalate raphide crystals. We have shown that raphide‐associated proteins could guide biomineralization, and the profilins found are potential allergens.
... Although these are calcium-rich vegetables, they are also high in oxalic acid, and calcium bioavailability appears to be only ~5% (Heaney, Weaver, and Recker 1988;Mangels 2014). However, steaming and especially boiling (and discarding the water) can considerably reduce oxalic acid content (by ~30-80%) (Massey 2007;Chai and Liebman 2005). Thus, more human studies assessing bioavailability with different cooking methods would be helpful in this field (Heaney, Weaver, and Recker 1988). ...
... Dietary oxalates that occur due to the presence of calcium oxalate are detrimental to health as they are associated with aggravation of kidney stones and malabsorption of calcium when foods containing high amounts of oxalate are consumed [25]. For this reason, they need to be eliminated or reduced to acceptable levels since the oxalate restriction, which is defined as the dietary oxalate limit, is no more than 40 -50 mg [26]. ...
... Although these are calcium-rich vegetables, they are also high in oxalic acid, and calcium bioavailability appears to be only ~5% (Heaney, Weaver, and Recker 1988;Mangels 2014). However, steaming and especially boiling (and discarding the water) can considerably reduce oxalic acid content (by ~30-80%) (Massey 2007;Chai and Liebman 2005). Thus, more human studies assessing bioavailability with different cooking methods would be helpful in this field (Heaney, Weaver, and Recker 1988). ...
Since the beginning of the 21st century, interest in vegan diets has been rapidly increasing in most countries. Misconceptions about vegan diets are widespread among the general population and health professionals. Vegan diets can be health-promoting and may offer certain important advantages compared to typical Western (and other mainstream) eating patterns. However, adequate dietary sources/supplements of nutrients of focus specific to vegan diets should be identified and communicated. Without supplements/fortified foods, severe vitamin B12 deficiency may occur. Other potential nutrients of focus are calcium, vitamin D, iodine, omega-3 fatty acids, iron, zinc, selenium, vitamin A, and protein. Ensuring adequate nutrient status is particularly important during pregnancy, lactation, infancy, and childhood. Health professionals are often expected to be able to provide advice on the topic of vegan nutrition, but a precise and practical vegan nutrition guide for health professionals is lacking. Consequently, it is important and urgent to provide such a set of dietary recommendations. It is the aim of this article to provide vegan nutrition guidelines, based on current evidence, which can easily be communicated to vegan patients/clients, with the goal of ensuring adequate nutrient status in vegans.
... The concentrations of phytates, oxalates, tannins and Cynogenic glyconides in S. alternata are 5.37 mg/100g, 2.95 mg/100g, 4.29 mg/100g and 7.53 mg/100g respectively shown in Figure 2. Cynogenic glyconides has the highest value while oxalate has the least value. High value of oxalate in human diet can increase the risk of renal calcium absorption and has been implicated as a source of kidney stones [8]. Whereas high value of tannin in foods interferes with protein absorption and digestive enzymes [3]. ...
Plant leaves play an essential part in health service as source of medicines. Since ancient age, plants are exploited as medicinal source. Various medicinal plants and their purified constituents have exposed helpful therapeutic potentials. The present study revealed the nutritional and antinutritional content of S. alternata which are known to possess the active medicinal chemical constituents. S. alternata has high content of the following essential minerals; Calcium, and Sodium with the following concentrations; 15.82 ± 0.01mg/100g and 10.55 ± 0.01 mg/100g, respectively. While relative amount of Potassium (5.89 ± 0.03mg/100g), Phosphorus (3.97 ± 0.02mg/100g) and Magnesium (6.29 ± 0.02mg/100g) were found to be present in the sample. The presence of Phytochemicals; Saponins, Alkaloids, Flavonoids Tannins and Hydrogen cyanide were evaluated to be 5.23± 0.01 mg/100g, 5.54 ± 0.0102mg/100g, 31.60 ± 0.0202mg/100g, 12.59 ± 0.0102mg/100g and 10.11 ± 0.0102mg/100g respectively. Anti-nutritional factors were recorded, thus; Phytate (5.37 ± 0.02 mg/100g), Oxalate (2.95 ± 0.01 mg/100g), Tannin (4.29 ± 0.01 mg/100g) and Cynogenic glyconide (7.53 ± 0.01 mg/100g). The presence of these phytochemicals and minerals point to the medicinally and nutritionally potent and should be used in the pharmaceutical industries for the formulation of drugs. All the anti-nutrient concentrations found exceeded the acceptable levels for human and animal consumption. However, the levels of anti-nutrients can be reduced through traditional processing techniques such as boiling, steaming, and cooking to make it safer for drugs development.
... The antinutritional composition of tomato fruits was determined by following different methods: the phytate content was measured according to the method described by Lucas and Markaka [35]; the tannins were determined using the method of Ogawa and Yazaki [36]; the oxalate content was measured using the methods of Chai and Liebman [37] and Umogbai et al. [38], and the results were calculated according to Attalla et al. [39] and Chai and Liebman [40]; the saponins content were measured according to AOAC, 1990 [41]; the trypsin inhibitors were determined as described by Korsinczky et al. [42] and calculated according to Lukanc et al. [43]; the α-amylase inhibitors were measured as described by Barrett and Udani [44]. ...
The tomato is one of the most important species in the food sector. For farmers, the increase in yield in greenhouse conditions by keeping a high quality of fruits represents a goal which is very difficult to achieve in these conditions. Therefore, the present study evaluates the influence that a continuous electric current might have on some biometrical, physiological and quality parameters of tomato fruits. The study was carried out in a greenhouse where tomato plants belonging to Qualitet F1 hybrid were treated with different continuous electric currents, under 5 DC sources, stabilized by the laboratory 0–30 V/0–5 A. During the research, the tomato plants were exposed to different electric current intensities or voltages on the plants or in the soil (T1-0.15 A; T2-0.30 A; T3-0.45 A; T4-1.5 V; T5-1.5 V-soil). The tomato plant samples were compared with an untreated control. In order to determine the influence of a continuous electric current, observations and determinations were made on tomato plants and fruits. The results highlighted significant differences between the treated and not treated plants, regarding the plant height, yield, firmness, acidity, total soluble solids, antioxidant activity, crude and dietary fibres, tannins, oxalates, saponins, α-amylase inhibitors, K, Mg, Fe and Zn content. Depending on the intensity of the electric current and the manner of application, the biometrical, physiological and quality parameters of tomato fruits were differently influenced. Both positive and negative influences were registered. More experiments are needed in order to establish a relation between the electric current intensity and the manner of application which can lead to better and higher tomato yields and quality in greenhouse conditions.
... The oxalic acid and calcium oxalate in the L .minor plant material was 70-110 and 100-160 mg/100 g fresh weight, respectively. For steamed or boiled spinach it was reported to contain between 460 and 800 mg/100 g fresh weight, respectively [21]. Our study resulted in an increase in urinary oxalic acid for both intervention arms, but not significantly different between the spinach and the L. minor group. ...
The growing world population will increase the demand for new sustainable foods and ingredients. Here we studied the safety and tolerance of Lemna minor, a new sustainable vegetable crop from the duckweed family. Twenty-four healthy adults consumed either L. minor plant material or spinach as vegetable (170 g fresh weight) as part of a warm meal on 11 consecutively days in a randomized controlled parallel trial design. The intervention meals had a different recipe for each day of the week. All participants had to report daily if they experienced gastric complaints, feelings of hunger, fullness, desire to eat, thirst, general health, nausea, and stool consistency. Only hunger, flatulence and constipation were significantly different between both intervention groups. At the start and end of the intervention, blood and urine were sampled in order to analyze biomarkers for general health, e.g ., kidney function, liver function, cardiovascular health, inflammation and iron status. Both intervention groups did not show significant differences for these biomarkers. In taste attributes the L. minor -based products showed in only a few specific cases a significant difference compared to the spinach-based products. Based on the results we conclude that 11 consecutive days intake of 170 g fresh weight L. minor plants as a cooked vegetable does not result in any adverse effect in healthy adult subjects.
... The oxalic acid content is suggested to increase with the ripeness of the fruit [66], and one of the suggested mechanisms for this increase is due to the conversion of ascorbic acid to oxalic acid as the fruit ripens. Cooking tomatoes, especially boiling fresh tomatoes, has been suggested to reduce their oxalic acid content [67]. The health-beneficial properties of tomatoes are studied the most in relation to their role in cancer prevention. ...
Simple Summary
The research outlined in this review paper discusses potential health benefits associated with a diet enriched with tomatoes and tomato products. This includes details of previous studies investigating the anticancer properties of tomatoes, protection against cardiovascular and neurodegenerative diseases and diabetes, maintenance of a healthy gut microbiome, and improved skin health, fertility, immune response, and exercise recovery. The specific parts of a tomato fruit that contribute these health benefits are also outlined. The potential disadvantages to a tomato-rich diet are detailed, especially the consumption of supplements that contain compounds found in tomatoes, such as lycopene. This review also discusses how the cultivation of tomato plants can affect the nutritional value of the fruit harvested. Different environmental growing conditions such as light intensity, growing media, and temperature are explained in terms of the impact they have on the quality of fruit, its nutrient content, and hence the potential health benefits acquired from eating the fruit.
Abstract
This review outlines the health benefits associated with the regular consumption of tomatoes and tomato products. The first section provides a detailed account of the horticultural techniques that can impact the quality of the fruit and its nutritional properties, including water availability, light intensity, temperature, and growing media. The next section provides information on the components of tomato that are likely to contribute to its health effects. The review then details some of the health benefits associated with tomato consumption, including anticancer properties, cardiovascular and neurodegenerative diseases and skin health. This review also discusses the impact tomatoes can have on the gut microbiome and associated health benefits, including reducing the risk of inflammatory bowel diseases. Other health benefits of eating tomatoes are also discussed in relation to effects on diabetes, the immune response, exercise recovery, and fertility. Finally, this review also addresses the negative effects that can occur as a result of overconsumption of tomato products and lycopene supplements.
Food insecurity is a pressing issue in Africa, aggravated by escalating drought, jeopardizing the region's ability to meet nutritional requirements for human health. In arid and semiarid regions, crop yield is severely affected by drought and salinity. Thus, obtaining an effective crop development requires striking the right balance between growth and defense. This review delves into the potential of CRISPR/Cas genome editing technology to tackle these challenges by improving the nutritional quality of climate‐resilient crops for SSA in the context of drought and soil salinity. We describe in detail opportunities for climate‐resilient crops with nutritional traits that could be developed using CRISPR/Cas systems for potential cultivation in arid and semiarid regions of Africa. We discussed the crops, genes and specific pathways that could be targeted. Furthermore, we emphasize the importance of aligning these scientific solutions with evolving policy frameworks, particularly favorable biosafety regulations concerning genome editing. In addition, we underscore the significance of capacity‐building programs, which have the potential to revolutionize crop value chains, tapping solutions enabled through genome editing. By strategically integrating CRISPR/Cas technology and supporting policies alongside capacity‐building initiatives and communication strategies, Africa can bolster food and nutritional security amidst climate change challenges. This approach not only addresses immediate nutritional needs but also fosters long‐term resilience in the region's agricultural systems.
The growing focus on balanced diets and health-enhancing foods has underscored the importance of functional crops like yam ( Dioscorea spp.), which serves as both a nutritional staple and a source of medicinal bioactives. Yam is consumable subterranean rhizomes or tubers, derived from plant sources in the Dioscorea genus. More than 90 of the roughly 600 yam species found in the world are found in East Asia. Additionally, yam contains bioactive compounds, which are non-nutritive components with vital health benefits, including phenolic compounds, saponins, tannins, and flavonoids, which contribute to its diverse therapeutic potential. Despite the numerous benefits inherent in yams, they also offer huge healthy perks, like antioxidants, anti-inflammatory, hypoglycemic, antimicrobial, and anti-tumor outcomes, making them important food candidates in the nutraceutical and pharma sectors. This review synthesizes current knowledge on nutritional composition, bioactive properties, extraction methods, therapeutic potentials, biological properties and administration. Strategies to enhance its utilization for greater impact are also discussed. This review highlights the potential of yam as a functional food, emphasizing its role in promoting dietary diversity and contributing to the prevention and management of non-communicable diseases, while also exploring associated challenges, emerging applications, and future research directions.
Graphical Abstract
Calcium (Ca) is a beneficial mineral for maintaining different physiological activities and is involved in preventing several diseases in human beings. Regular dietary Ca intake is therefore essential. However, the quantity required varies with different age groups. Various leafy vegetables act as a good source of Ca but some natural or physiological factors like phytate and vitamin D may influence Ca absorption from the Gastrointestinal Tract (GIT) thereby affecting the bioavailability of Ca. Methods like boiling and fermentation can be used to increase the bioavailability of Ca. Understanding Ca bioavailability from leafy vegetables can therefore be helpful for a proper recommendation of dietary Ca supplementation.
Root and tuber crops are the second major edible energy sources, providing nutritional security to resource-poor populations in developing countries, especially Africa, Asia, and Latin America. The breeding barriers in genetic improvement of root and tuber crops can be overcome by targeted gene transfer or genetic modification technologies. However, the potential of genetic modification for enhancing the desirable traits in root and tuber crops is not fully explored. The chapter outlines the major problems in the cultivation, breeding, and nutritional aspects of selected tropical root and tuber crops, the advantages of using genetic modification technologies, and how they can complement traditional crop improvement programs in tropical root and tuber crops. The principles and methods of genetic modification, current status or applications, and the prospects of transgenics in these crops are briefly outlined. The guidelines governing genetic modification technologies, challenges, and the biosafety issues related to the release of transgenics are also discussed.
In the dynamic landscape of agriculture and food science, incorporating emergent crops appears as a pioneering solution for diversifying agriculture, unlocking possibilities for sustainable cultivation and nutritional bolstering food security, and creating economic prospects amid evolving environmental and market conditions with positive impacts on human health. This review explores the potential of utilizing emergent crops in Mediterranean environments under current climate scenarios, emphasizing the manifold benefits of agricultural and food system diversification and assessing the impact of environmental factors on their quality and consumer health. Through a deep exploration of the resilience, nutritional value, and health impacts of neglected and underutilized species (NUS) such as quinoa, amaranth, chia, moringa, buckwheat, millet, teff, hemp, or desert truffles, their capacity to thrive in the changing Mediterranean climate is highlighted, offering novel opportunities for agriculture and functional food development. By analysing how promoting agricultural diversification can enhance food system adaptability to evolving environmental conditions, fostering sustainability and resilience, we discuss recent findings that underscore the main benefits and limitations of these crops from agricultural, food science, and health perspectives, all crucial for responsible and sustainable adoption. Thus, by using a sustainable and holistic approach, this revision analyses how the integration of NUS crops into Mediterranean agrifood systems can enhance agriculture resilience and food quality addressing environmental, nutritional, biomedical, economic, and cultural dimensions, thereby mitigating the risks associated with monoculture practices and bolstering local economies and livelihoods under new climate scenarios.
Minerals are vital nutrients required for the growth and metabolism of the body. These are naturally occurring elements which are present in rocks, earth and various foods. They are required by the human body in different proportions as per their functions. Hence, they are classified as macro- and micronutrients. Minerals as nutraceutical also plays an important role as substrates for biochemical reactions; co-factors of enzymatic reactions; inhibitors of enzymatic reactions; compounds that improve nutrient absorption and/or stability; selective growth factors for beneficial gastrointestinal bacteria; fermentation substrates for beneficial oral, gastric or intestinal bacteria; selective inhibitors of deleterious intestinal bacteria; and absorbents and sequestrants that bind to and remove unfavourable compounds; minerals play a critical role in human health. In this chapter, the important role of minerals in various human body functions and their bioavailability has been elaborated. The effects of various factors on the absorption and function of different minerals have been discussed in detail. Further, the effect of food processing and cooking technique on the nutritional value of the minerals has also been discussed thoroughly.
This book is a comprehensive review of secondary metabolite production from plant tissue culture. The editors have compiled 12 meticulously organized chapters that provide the relevant theoretical and practical frameworks in this subject using empirical research findings. The goal of the book is to explain the rationale behind in vitro production of secondary metabolites from some important medicinal plants. Biotechnological strategies like metabolic engineering and the biosynthesis, transport and modulation of important secondary metabolites are explained along with research studies on specific plants. In addition to the benefits of secondary metabolites, the book also aims to highlight the commercial value of medicinal plants for pharmaceutical and healthcare ventures.
Topics covered in this part include:
1. In vitro propagation and tissue culture for several plants including Withania somnifera (L.) Dunal, Aloe vera, Oroxylum indicum (L) Kurz, Ocimum basilicum L, Rhubarb, Tea, and many others (including plants in Northern India).
2. Genetic Improvement of Pelargonium
3. Bioactive Components in Senna alata L. Roxb
4. Plant tissue culture techniques
The book caters to a wide readership. It primarily prepares graduate students, researchers, biotechnologists, giving them a grasp of the key methodologies in the secondary metabolite production. It is a secondary reference for support executives, industry professionals, and policymakers at corporate and government levels to understand the importance of plant tissue culture and maximizing its impact in the herbal industry.
The nutritional consequences of short bowel depend on the site and extent of resection, the presence or absence of colon in continuity, the integrity and degree of adaptation within the remaining bowel as well as underlying disease. Understanding the anatomical and physiological changes facilitates the provision of individualised dietary advice to optimise absorption, reduce stoma/stool losses and minimise complications.
Balance studies show that short bowel patients develop an adaptive hyperphagia that supports an increased oral energy and protein intake to compensate for malabsorption and that the optimal dietary composition to promote absorption depends on the presence or absence of colon. Jejunum-colon patients benefit from a diet that is high in carbohydrate with fibre to tolerance, moderate in long-chain triglycerides with partial substitution of medium-chain triglycerides to increase energy absorption as required and low in oxalate to reduce the risk of renal stones. Jejunostomy patients should take a high fat diet with added salt and restrict hypotonic fluids with substitution of oral rehydration solution.
Nutritional outcomes are improved by intensive education with individualised verbal and written advice, to help patients to understand how their bowel function has changed, the importance of hyperphagia and rationale for dietary advice, appropriate food choices, restriction of hypotonic fluids and substitution of oral rehydration solution. The dietary regimen should be tailored to the patient’s preferences and lifestyle and regularly reviewed and adjusted in response to intestinal adaptation or changes in their condition to aid compliance.
Optimal nutritional care is best supported by a multidisciplinary team where there is close liaison between doctors, nurses, dietitians and pharmacists. Dietitians play a key role in assessing the patient’s nutritional status and requirements, providing diet and fluid advice that is appropriate to their anatomy, treatment goal and lifestyle, monitoring the impact of dietary changes on intestinal function and quality of life and coordinating the relative nutritional contributions from diet, oral nutrient supplements, enteral or parenteral support.
Owing to its special nutritional and functional properties, sweet potato (Ipomoea batatas [L.] Lam) has become a research subject in recent years. Bioactive carbohydrates, proteins, lipids, carotenoids, anthocyanins, phenolic acids and minerals are the diverse nutrients present in the leaves of sweet potato. Different health benefits, such as antioxidant, cardioprotective, anti-inflammatory, anticancer, antidiabetic, antimicrobial and antiobesity, contribute to the specific composition of sweet potato leaves. Sweet potato leaves remain substantially underutilized in the commercial sense. To promote human health, sweet potatoes can be further grown as a sustainable crop for
various nutritionally-enhanced and value-added food items. Therefore, the goal of this chapter is to give a broad view of the nutritional value, phytochemical composition and health properties of sweet potato leaves.
Legume seeds, particularly those of the Phaseolus lunatus (L.), are an important source of vegetable protein, fiber and micronutrients in the diet of the Ivorian population. However, these seeds contain anti-nutritive factors that limit their use. This study allowed us to evaluate the effect of cooking time on the nutritional and anti-nutritional parameters of Phaseolus lunatus (L.) bean seeds for a better utilization of these seeds. Red and black seeds harvested at stage 4 (52 days) of Phaseolus lunatus (L.) bean were cooked at 100 °C for 45, 60 and 75 minutes. The nutritional and anti-nutrional composition was determined on uncooked (control) and cooked samples. The results obtained showed an increase in carbohydrate (64.16 to 71.56%), energy value (29.68 to 36.27%) and fiber (4.62 to 6.05%) followed by a reduction in protein (4.62 to 6.05%), ash (4.62 to 6.05%) and fat (4.62 to 6.05%). The same cooking also caused a reduction in total phenols (59.18 to 72.49%), phytates (33.32 to 39.18%), oxalates (64.64 to 68.91%), tannins (62.07 to 67.59%), cyanidric acid (58.18 to 61.38%) and antioxidant activity (53.71 to 63.94%). The analysis of the seeds cooked at different times (45, 60 and 75 minutes) also shows us that the B vitamins and minerals decrease during cooking. The consumption of Phaseolus lunatus bean seeds cooked at 45 minutes could be recommended in human diet due to the decrease of oxalates and phytates to prevent and treat some diseases such as cancer, inflammatory diseases, cardiovascular diseases and neurogenerative diseases.
Cooking at home has experienced a decline in many countries since the mid-20th century. As rates of obesity have increased, there has been an emphasis on more frequent home cooking, including its incorporation into several food-based dietary guidelines around the world as a strategy to improve dietary quality. With the recent trend towards the adoption of diets richer in plant-based foods, many consumers cooking at home may now be cooking plant foods such as vegetables, potatoes and pulses more often. It is, therefore, timely to explore the impact that different home cooking methods have on the range of nutrients (e.g. vitamin C and folate) and bioactive phytochemicals (e.g. carotenoids and polyphenols) that such plant foods provide, and this paper will explore this and whether advice can be tailored to minimise such losses. The impact of cooking on nutritional quality can be both desirable and/or undesirable and can vary according to the cooking method and the nutrient or phytochemical of interest. Cooking methods that expose plant foods to high temperatures and/or water for long periods of time (e.g. boiling) may be the most detrimental to nutrient content, whereas other cooking methods such as steaming or microwaving may help to retain nutrients, particularly those that are water-soluble. Dishes that use cooking liquids may retain nutrients that would have been lost through leaching. It may be helpful to provide the public with more information about better methods to prepare and cook plant foods to minimise any nutrient losses. However, for some nutrients/phytochemicals the insufficient and inconsistent research findings make clear messages around the optimal cooking method difficult, and factors such as bioaccessibility rather than just quantity may also be important to consider.
The consumption of plant foods has been encouraged to cover a high proportion of the diet due to their health benefits. However, the occurrence of anti-nutrients in plant foods, especially soluble oxalate, is often neglected. High intake of soluble oxalate from the diet can increase the risk of kidney stone formation as well as mineral deficiency and restriction of dietary oxalate is the only way to reduce urinary oxalate. This review discussed the existing knowledge on effects of food processing on oxalate contents in plant foods. Leaching, fermentation and cooking with calcium sources could be considered as the most efficient methods to reduce soluble oxalate. Time, temperature and properties of the food (pH, fibre and fat contents, and preparation methods) are the major factors determining the treatment efficiency for oxalate reduction. Pulsed electric field, ultrasonication and enzymatic treatments have been proven as potential methods to diminish oxalates.
Whole foods plant-based approaches to eating place an emphasis on the intake of fruits, vegetables, whole grains, and legumes and have many health benefits. While there are key nutrients and phytochemicals that can contribute to the purported health benefits, practitioners and patients should also be advised of key nutrients for which intake may be compromised when following this dietary pattern. With careful planning and utility of dietary supplements, individuals can achieve optimal intake of calcium, iron, vitamin D, omega 3 fatty acid—docosahexaenoic acid (DHA), and vitamin B12 and experience the health benefits of a dietary fiber and a host of phytochemicals. This article presents the health benefits of these food substances and approaches for overcoming nutrients of concern when following whole food plant-based eating patterns.
Oxalates occur as end products of metabolism in a number of plant tissues; some leafy plants and some root crops contain markedly high levels of soluble and insoluble oxalates. When consumed these oxalates can bind calcium and other minerals. Measurement of oxalate content in vegetables commonly consumed in New Zealand shows that cooking reduces the oxalate content of the food by leaching losses into the cooking water. Roots and brassicas grown in New Zealand appear to contain relatively low levels of oxalates. Leafy vegetables such as silverbeet and NZ spinach appear to approach and exceed levels found in rhubarb stalks, although New Zealand silverbeet stems contain lower levels.
Oxalic acid and its salts occur as end products of metabolism in a number of plant tissues. When these plants are eaten they may have an adverse effect because oxalates bind calcium and other minerals. While oxalic acid is a normal end product of mammalian metabolism, the consumption of additional oxalic acid may cause stone formation in the urinary tract when the acid is excreted in the urine. Soaking and cooking of foodstuffs high in oxalate will reduce the oxalate content by leaching. The mean daily intake of oxalate in English diets has been calculated to be 70-150 mg, with tea appearing to contribute the greatest proportion of oxalate in these diets; rhubarb, spinach and beet are other common high oxalate-content foods. Vegetarians who consume greater amounts of vegetables will have a higher intake of oxalates, which may reduce calcium availability. This may be an increased risk factor for women, who require greater amounts of calcium in the diet. In humans, diets low in calcium and high in oxalates are not recommended but the occasional consumption of high oxalate foods as part of a nuritious diet does not pose any particular problem.
About 75% of all kidney stones are composed primarily of calcium oxalate and hyperoxaluria is a primary risk factor for this disorder. Since absorbed dietary oxalate can make a significant contribution to urinary oxalate levels, oxalate from legumes, nuts, and different types of grain-based flours was analyzed using both enzymatic and capillary electrophoresis (CE) methods. Total oxalate varied greatly among the legumes tested, ranging from 4 to 80 mg/100 g of cooked weight. The range of total oxalate of the nuts tested was 42–469 mg/100 g. Total oxalate of analyzed flours ranged from 37 to 269 mg/100 g. The overall data suggested that most legumes, nuts, and flours are rich sources of oxalate.
Food oxalate analysis in foods is problematic due to the wide range of interfering substances. To prevent oxalate generation during sample preparation mild and rapid extraction methods were evaluated. Soluble oxalate was extracted with distilled water and total oxalate was extracted with 2 N hydrochloric acid. Filtrates were analysed using the HPLC enzyme reactor method. Evaluation yielded a high level of precision and recovery. Glyoxylic acid, d/l malic acid, isocitric acid, oxaloacetic acid, pyruvate, mesoxalic acid, ascorbic acid, d(+) glucose, d(−) fructose, chlorogenic acid, caffeic acid could be excluded as a source of oxalate generation during extraction with hot acids. The soluble and total oxalate content of about 150 food samples were investigated.
Oca (Oxalis tuberosa Mol.) or New Zealand yam, in common with other members of this genus, contains oxalate, an antinutritive factor. Twelve South American and two New Zealand cultivars of oca were analyzed for total and soluble oxalate contents of the tubers. The range of total oxalate levels was 92-221 mg/100 g of fresh weight. Levels of soluble and total oxalate extracted from the tubers were not significantly different, suggesting that no calcium oxalate is formed in the tubers. The oxalate concentrations obtained in this study for oca suggest that previously reported values are too low and that oca is a moderately high oxalate-containing food. This is the first report of a tuber crop containing moderate to high levels of soluble oxalates in the tubers and no insoluble oxalates.
We extended the study of oxalate bioavailability by testing 7 additional food items: brewed tea, tea with milk, turnip greens, okra, peanuts and almonds. Nine normal subjects ingested a large serving of each of these items. The bioavailable oxalate was calculated from the increment in urinary oxalate during 8 hours after ingestion and bioavailability was determined as the percentage of total oxalate content in a given food item represented by bioavailable oxalate. Brewed tea and tea with milk, with a high oxalate content, had a low bioavailable oxalate level (1.17 and 0.44 mg. per load) because of the low oxalate availability (bioavailability of 0.08 and 0.03%). Turnip greens, with a satisfactory oxalate bioavailability (5.8%), had a negligible effect on urinary oxalate excretion, since oxalate content was relatively low (12 mg. per load). Okra, with a moderate oxalate content (264 mg. per load) had a negligible bioavailable oxalate (0.28 mg. per load). Only peanuts and almonds provided a moderate increase in oxalate excretion (3 to 5 mg. per load) due to the modest oxalate content (116 and 131 mg. per load) and oxalate bioavailability (3.8 and 2.8%). Thus, the ability of various oxalate-rich foods to augment urinary oxalate excretion depends not only on oxalate content but on the bioavailability.
This new reagent kit for the quantitative measurement of oxalate in urine is a modification of an earlier Sigma oxalate assay procedure (procedure no. 590), a coupled enzyme assay involving oxalate oxidase and horseradish peroxidase. The new analytical procedure includes methods for processing urine specimens to eliminate interference with oxalate color development at 590 nm by ascorbic acid, divalent cations, and other urinary constituents. The reaction is complete in less than 5 min, and results are linearly related to oxalate concentration up to at least 1 mmol/L. Assay sensitivity and within-run and between-run precision were within the limits acceptable for other urinary oxalate procedures. Analytical recovery of added oxalate was close to 100%. This specific, simple, rapid procedure is suitable for routine clinical use.
An automated enzyme immunoassay for human lutropin for use with the Abbott IMx analyzer is described. The assay provides results in approximately 40 min with a sensitivity of 0.25 int. units of LH per liter for up to 23 serum or plasma samples. Cross-reactivity with follitropin (2000 int. units/L) and thyrotropin (2 int. units/L) was negligible; it was 0.016% with human choriogonadotropin (1 X 10(6) int. units/L). There was no interference by high concentrations of bilirubin (0.5 g/L), hemoglobin (7.50 g/L), or triglycerides (13.5 g/L). Intra-, inter-, and total assay CVs were less than or equal to 3.75%, less than or equal to 7.1%, and less than or equal to 7.94%, respectively. Values obtained with the IMx correlated well (r = 0.98, n = 194) with values obtained with Diagnostic Products' LH Double Antibody RIA, and Serono's LH MAIAclone assay. This assay should be useful for small to medium-size laboratories involved in the clinical diagnosis of reproductive pathology.
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A new quantitative gas chromatographic (GC) method has been developed for the determination of oxalic acid in foods. Solid sample is extracted with water (soluble oxalic acid) or 2N hydrochloric acid (total oxalic acid) at room temperature. An aliquot of sample extract is evaporated to dryness, and the oxalic acid in the residue is methylated with 7% hydrochloric acid-methanol. The reaction mixture is extracted with chloroform, and dimethyl oxalate is quantitated by GC. Recovery of oxalic acid added to liquid samples averaged 100.6%; recoveries from extracts of solid samples were 96.2-99.5 and 97.2-100.1% for water and hydrochloric acid extractions, respectively. Results are shown for determination of oxalic acid in spinach and beverages. The technique is simple, rapid, and accurate, and small samples may be used. The limit of determination is 20 micrograms.
Dietary restriction of oxalate intake has been used as therapy to reduce the risk of recurrence of calcium oxalate kidney stones. Although urinary oxalate is derived predominantly from endogenous synthesis, it may also be affected by dietary intake of oxalate and calcium. The risk of increasing urinary oxalate excretion by excessive consumption of dietary oxalate is greatest in individuals with a high rate of oxalate absorption, both with and without overt intestinal disease. Although oxalate-rich foods enhanced excretion of urinary oxalate in normal volunteers, the increase was not proportional to the oxalate content of the food. Only eight foods--spinach, rhubarb, beets, nuts, chocolate, tea, wheat bran, and strawberries--caused a significant increase in urinary oxalate excretion. Restriction of dietary calcium enhances oxalate absorption and excretion, whereas an increase in calcium intake may reduce urinary oxalate excretion by binding more oxalate in the gut. This review of the literature indicates that initial dietary therapy for stone-forming individuals can be limited to the restriction of foods definitely shown to increase urinary oxalate. The effects of oxalate-restricted diets on urinary oxalate should be evaluated by means of laboratory analyses of urine composition. Subsequent long-term therapy can be recommended if beneficial results are obtained from oxalate restriction at an appropriate calcium intake.
Dietary oxalate is currently believed to make only a minor contribution (< 20%) to urinary oxalate excretion. A recent prospective study of stone disease suggested that dietary oxalate may be a significant risk factor. This observation led us to re-evaluate the contribution of dietary oxalate to urinary oxalate excretion. Previous studies have been hampered by inaccurate food composition tables for oxalate and inadequate methods for studying intestinal oxalate absorption. This evidence as well as factors that modify oxalate absorption are reviewed. New approaches to measure food oxalate and intestinal oxalate absorption have been examined. Capillary electrophoresis appears to be well suited for the analysis of the oxalate content of food. Two individuals consumed an oxalate-free formula diet for 7 days. This diet decreased urinary oxalate excretion by an average of 67% (18.6 mg per 24 hours) compared to oxalate excretion on self-selected diets. The absence of detectable oxalate in feces by day 6 of the diet suggested that the intestinal absorption was minimal. However, an effect of the formula diet on endogenous oxalate synthesis cannot be excluded. Restoring oxalate to the formula diet increased urinary oxalate excretion and illustrates that this experimental protocol may be well-suited for studying oxalate absorption and factors that modify it. Our results suggest that the intestinal absorption of dietary oxalate makes a substantial contribution to urinary oxalate excretion and that this absorption can be modified by decreasing oxalate intake or increasing the intakes of calcium, magnesium, and fiber.
There is currently intense research interest in secondary plant metabolites because of their potential preventative effects on the chronic diseases of Western societies, especially cardiovascular disease and cancer. To date most of the research has focused on the identification of plant-derived substances and their potential protective effects against specific chronic diseases. The important issue of determining the optimal intake of those substances, such that the beneficial effects are maximized without manifestation of adverse effects, has yet to be addressed in most cases. Furthermore, there are no specific functional markers that can be used to assess optimal intake, although it may be possible to use biomarkers such as serum cholesterol if the rest of the diet is strictly controlled. The present review discusses a wide range of substances associated with plants, including dietary fibre, resistant starch, oligosaccharides, phyto-oestrogens, phytosterols, flavonoids, terpenes and isothiocyanates, and attempts where possible to indicate optimal intakes and to suggest functional markers.
It is believed that soluble oxalate has higher bioavailability than insoluble oxalate. Oca (Oxalis tuberosa) is moderately high in oxalate and contains oxalate in soluble form only. We estimated the bioavailability of oxalate in oca based on the urinary excretion of oxalate after oxalate loading with oca to estimate the bioavailability of oxalate in oca. We also clarified whether bioavailability differs in various oxalate loads from the same food source and studied the effect of an additional calcium source on the bioavailability of oxalate from oca.
Four men and 4 women ingested 50, 100 and 150 gm. oca as well as 100 gm. oca with 100 gm. sour cream. Oxalate was measured in a 6-hour urine sample from each volunteer.
The mean bioavailability of oxalate from oca plus or minus standard deviation was 1.44% +/- 1.31% during the 6-hour period after intake. There was no significant difference in oxalate bioavailability among oxalate intake levels in this study, although oca consumption with sour cream significantly decreased the uptake of oxalate (p <0.01). The variation in bioavailability among individuals was high in our study.
The bioavailability of oxalate in oca appears to be similar to that in spinach. However, bioavailability varies among individuals and depends on other constituents of a combined meal.
Leafy vegetables such as spinach (Spinacia oleracea) are known to contain moderate amounts of soluble and insoluble oxalates. Frozen commercially available spinach in New Zealand contains 736.6+/-20.4 mg/100g wet matter (WM) soluble oxalate and 220.1+/-96.5mg/100g WM insoluble oxalate. The frozen spinach contained 90mg total calcium/100g WM, 76.7%of this calcium was unavailable as it was bound to oxalate as insoluble oxalate. The oxalate/calcium (mEq) ratio of the frozen spinach was 4.73. When frozen convenience food is grilled there is no opportunity for the soluble oxalates to be leached out into the cooking water and discarded. Soluble oxalates, when consumed, have the ability to bind to calcium in the spinach and any calcium in foods consumed with the spinach, reducing the absorption of soluble oxalate. In this experiment 10 volunteers ingested 100g grilled spinach alone or with 100g additions of cottage cheese, sour cream and sour cream with Calci-Trim milk (180 g) and finally, with 20g olive oil. The availability of oxalate in the spinach was determined by measuring the oxalate output in the urine over a 6-hour and 24-hour period after intake of the test meal. The mean bioavailability of soluble oxalate in the grilled spinach was 0.75+/-0.48% over a 6-hour period after intake and was 1.93+/-0.85% measured over a 24-hour period. Addition of sour cream and Calci-Trim milk reduced the availability of the oxalate in the spinach significantly (P<0.05) in both the 6-hour and 24-hour collection periods.
Oxalate bioavailability is an important determinant of whether the consumption of a particular food is a high risk in individuals predisposed to kidney stones. We estimated and compared oxalate absorption from a high oxalate containing legume (black beans) and a high oxalate containing nut (almonds). We also compared an isotope method using extrinsically labeled oxalate and an oxalate load method to assess oxalate absorption.
Six male and 5 female subjects participated in the 4 oxalate load tests, namely almonds, almonds with 20 mg C2-oxalic acid, black beans and black beans with 20 mg C2-oxalic acid. Each treatment provided a total of 120 mg oxalate, after which timed urine samples were collected for the analysis of oxalate, calcium and creatinine.
Average oxalate absorption from the 2 almond treatments (5.9%) using the oxalate load method was significantly higher than that from the 2 black bean treatments (1.8%) during the 24-hour post-oxalate load collection period. In contrast, C2-oxalic acid absorption from the almond (7.9%) and black bean (8.6%) treatments did not significantly differ.
The higher oxalate absorption from almonds than from black beans suggests that the relative amount of soluble and insoluble oxalate in food has an important role in the determination of oxalate absorption. Since extrinsically provided C2-oxalate and oxalate naturally occurring in the high oxalate test foods appeared to be differentially absorbed, the data do not support the use of extrinsically labeled oxalate to assess food oxalate absorption.
Revised manuscript received February 15 Accepted February 18 This study was supported by a grant from the VP Foundation
- Chai
- Liebman
Received for review November 9, 2004. Revised manuscript received February 15, 2005. Accepted February 18, 2005. This study was supported by a grant from the VP Foundation, Graham, NC. JF048128D 3030 J. Agric. Food Chem., Vol. 53, No. 8, 2005 Chai and Liebman
- Albihn P. B. E.