An Investigation on Phenolic and Antioxidant Capacity of Under-utilized Food Legumes Consumed in China

Unveiling the nutrient-wealth of black soybean: A holistic review of its bioactive compounds and health implications

Legumes, an essential component of staple diets, hold a prominent place in global cuisines. Soybean stands out as a widely cultivated legume and is valued for its high protein content, dietary fiber, and rich micronutrients. Several varieties of soybean are available, of which black and yellow varieties show dominance in varied countries and cultures. Over time, the cultivation and consumption of black soybeans have markedly reduced compared to the yellow variety. Despite its rich nutritional and therapeutic indices, it has lost its usage over time. Traditionally, it was utilized in oriental medicine for detoxification and anti-inflammatory potential. However, the antinutrients present in black soybean limit its utilization in the food sector due to their interference with overall nutrient absorption. Several studies in the last few decades have focused on reducing the content of antinutritional factors. However, the information on the use of different processing techniques, both singly and in blends, to reduce antinutrients and enhance the bioaccessibility, bioavailability, and bioactivity of bioactive compounds and varied nutrients is limited and fragmented. Furthermore, studies have highlighted black soybeans' protective effects against various degenerative diseases. However, the studies on the effect of processing to enhance its antioxidative properties to make them a sought-after food commodity with nutraceutical potential and therapeutic efficacy are limited and widely scattered. The review aims to consolidate knowledge of diverse processing methods to improve their nutritional and bioactive profile for wider applications in the food and pharmaceutical industries. Further, it has also highlighted its nutraceutical properties for developing varied functional foods against degenerative diseases to have better therapeutic efficacy.

Elevating the significance of legume intake: A novel strategy to counter aging-related mitochondrial dysfunction and physical decline

Mitochondrial dysfunction increasingly becomes a target for promoting healthy aging and longevity. The dysfunction of mitochondria with age ultimately leads to a decline in physical functions. Among them, biogenesis dysfunction and the imbalances in the metabolism of reactive oxygen species and mitochondria as signaling organelles in the aging process have aroused our attention. Dietary intervention in mitochondrial dysfunction and physical decline during aging processes is essential, and greater attention should be directed toward healthful legume intake. Legumes are constantly under investigation for their nutritional and bioactive properties, and their consumption may yield antiaging and mitochondria-protecting benefits. This review summarizes mitochondrial dysfunction with age, discusses the benefits of legumes on mitochondrial function, and introduces the potential role of legumes in managing aging-related physical decline. Additionally, it reveals the benefits of legume intake for the elderly and offers a viable approach to developing legume-based functional food.

Multivariate Analysis of Biochemical Properties Reveals Diversity among Yardlong Beans of Different Origins

This study analyzed the nutrient levels, secondary metabolite contents, and antioxidant activities of 35 yardlong bean accessions from China, Korea, Myanmar, and Thailand, along with their key agronomic traits. Significant variations were found in all the parameters analyzed (p < 0.05). The crude fiber (CFC), dietary fiber (DFC), total protein, and total fat contents varied from 4.10 to 6.51%, 16.71 to 23.49%, 22.45 to 28.11%, and 0.59 to 2.00%, respectively. HPLC analysis showed more than a 10-fold difference in vitamin C level (0.23 to 3.04 mg/g), whereas GC-FID analysis revealed the dominance of palmitic acid and linoleic acid. All accessions had high levels of total unsaturated fatty acids, which could help in preventing cardiovascular disease. Furthermore, total phenolic, tannin, and saponin contents ranged between 3.78 and 9.13 mg GAE/g, 31.20 and 778.34 mg CE/g, and 25.79 and 82.55 mg DE/g, respectively. Antioxidant activities like DPPH• scavenging, ABTS•+ scavenging, and reducing power (RP) ranged between 1.63 and 9.95 mg AAE/g, 6.51 and 21.21 mg TE/g, and 2.02, and 15.58 mg AAE/g, respectively. Days to flowering, total fat, palmitic acid, oleic acid, and TPC were significantly influenced by origin and genotype differences, while seeds per pod, one-hundred seeds weight, CFC, DFC, vitamin C, RP, and TSC were not affected by these factors. Multivariate analysis categorized the accessions into four clusters showing significant variations in most of the analyzed parameters. Correlation analysis also revealed significant relationships between several noteworthy parameters. Overall, this comprehensive analysis of biochemical factors revealed diversity among the different yardlong bean varieties. These findings could have practical applications in industries, breeding programs, and conservation efforts.

Comparison of Nutritional Diversity in Five Fresh Legumes Using Flavonoids Metabolomics and Postharvest Botrytis cinerea Defense Analysis of Peas Mediated by Sakuranetin

Legumes possess several bioactive nutrients, including flavonoids, and the study of the flavonoid profile of legumes is of great significance to human health. Using widely targeted metabolomics, we revealed the flavonoid profiles of five popular fresh legumes: cowpea, soybean, pea, fava bean, and kidney bean. A total of 259 flavonoids were identified, and the flavonoid accumulation patterns of the five legumes were remarkably different. In addition to analyzing common and species-specific flavonoids in the five legumes, we also generalized representative flavonoids of various subclasses. We related these to the health-promoting effects of legumes. Furthermore, legumes' total flavonoid content and antioxidant system activity were also detected. Intriguingly, sakuranetin, the sole flavonoid phytoalexin that can be induced by UV radiation, was detected only in the peas by metabolomics. Meanwhile, we found that UV treatment could significantly increase the sakuranetin content and the postharvest Botrytis cinerea resistance of pea pods. This study provides clues for the target diet, industrial development of legumes, and a new idea for the postharvest preservation of peas.

Phenolic profile, alpha-amylase inhibitory activity, and in vitro glycemic index of adzuki beans

Regular consumption of low-glycemic index (GI) foods is a common strategy for type 2 diabetes patients. To evaluate the potential application of adzuki beans in low-GI foods, the phenolic profile and alpha-amylase inhibitor (α-AI) activity of four varieties of adzuki beans (G24, Te Xiao Li No. 1, Gui Nong No. 1, and Qian Xiao Hei) were determined. The starch digestibility properties and in vitro glycemic index (IVGI) of these beans were also evaluated using the in vitro digestion model coupled with 3,5-dinitrosalicylic acid colorimetry. The results indicated that these adzuki beans, containing numerous phenolics, showed inhibitory activities to alpha-amylase with the α-AI activities between 1.760 ± 0.044 and 3.411 ± 0.186 U/g. The resistant starch (RS) contributed predominantly to the total starch with proportions between (69.78 ± 2.45%) and (81.03 ± 0.06%); Te Xiao Li No. 1 was the highest compared with the other varieties. The adzuki beans were categorized into low- or medium-GI foods, and the IVGI ranged from (39.00 ± 0.36) to (56.76 ± 4.21). These results suggested that adzuki beans can be used as a component of low-GI foods.

Insight into the antioxidant activities of ten Fabaceae plant species that are medicinally used by the Aucan Tribal Peoples from the Republic of Suriname (South America)

Fabaceae are associated with a high antioxidant activity (AA) and a high total phenolic (TPC), total flavonoid (TFC), and selenium content (SeC). In this study, the aqueous extracts from ten Fabaceae species that are medicinally used by the Aucan Tribal Peoples from Suriname (South America), were evaluated for AA using a DPPH and a FRAP assay, and for TPC, TFC, and SeC using Folin-Ciocalteu's, an AlCl3 colorimetric, and an azure B-based method. Associations between pairs of these variables were determined by Pearson correlation coefficient. One-way ANOVA with post-hoc Tukey's test was used to evaluate the data for statistically significant differences (p < 0.05). The I. stipularis (bark), C. guyanensis (bark), A. jupunba (twigs), and M. urens (fruit) extracts had the highest DPPH IC50 values (36 - 70 μg/mL) and FRAP values (346 - 573 μM FeE/100 μg) and the highest TPC (25 - 41 GAEq/100 μg), TFC (21 - 39 REq/100 μg), and SeC (4 -17 μg/g). The values for the T. indica (leaf), P. macroloba (bark), M. pigra (whole plant), S. quinquangulata (leaf), A. sensitiva (whole plant), and L. leucocephala (leaf) extracts were > 10-fold lower. AA, TPC, TFC, and SeC correlated well with each other (correlation coefficient ≥ 0.83, p ≤ 0.0030). Thus, AA, TPC, TFC, and SeC may represent important determinants of the health benefits of the former four samples but not of the others. Future studies should focus on the precise contribution of AA, TPC, TFC, and SeC to the therapeutic value of medicinal Fabaceae.

Metabolic footprints of chitosan primed red kidney bean under restricted irrigation

Climate change has led to long term shift in temperature and weather regimes leading to unprecedented drought conditions. In this study varying degree of drought stress was imposed by restricting irrigation in red kidney bean along with application of chitosan as seed and foliar prime. LC-MS/MS was used to study the metabolic footprints (flavonoids and anthocyanin) in the red kidney bean varieties (BR 104 and VL Rajma 63). Presence of 14 flavonoid compounds and four anthocyanins (delphinidin>cyaniding>pelargonidin>malvidin) obtained from 0.25% chitosan primed red kidney bean were resolved through LC-MS/MS analysis. The concentration of flavonoid compounds in all the treatments was found in the order of naringenin>quercetin>luteolin>hesperetin>myricetin. Correlation studies revealed strong correlation of 0.95 among catechin-naringenin, galangin-hesperetin and epicatechin-kaempferol in BR 104 variety. Antioxidant activities were investigated by assessing radical scavenging activity, chelating power and reducing power assay in both varieties. Principle component (PC) analysis depicted through biplot was showed 44.7% contribution was found towards PC1 and 28.6% towards PC2 in BR 104 variety. 0.25% chitosan as seed and foliar priming with imposed drought stress was found to improve the antioxidant contents of seed by regulating polyphenols which have diverse role in stress management.

Effect of Traditional Cooking and In Vitro Gastrointestinal Digestion of the Ten Most Consumed Beans from the Fabaceae Family in Thailand on Their Phytochemicals, Antioxidant and Anti-Diabetic Potentials

The edible beans in Fabaceae have been used for foods and medicines since the ancient time, and being used more and more. It is also appeared as a major ingredient in dairy cooking menu in many regions including Thailand, a rich biodiversity country. Many studies reported on health benefits of their flavonoids, but there is no report on the effect of cooking on phytochemical profile and pharmacological potentials. Thus, this present study aims to complete this knowledge, with the 10 most consumed Fabaceae beans in Thailand, by determining the impact of traditional cooking and gastrointestinal digestion on their phytochemicals, their antioxidant and anti-diabetic activities using different in vitro and in cellulo yeast models. The results showed that Vigna unguiculata subsp. sesquipedalis were the richest source of phytochemicals, whereas the population of V. mungo, Phaseolus vulgaris, V. angularis, and V. unguiculata subsp. sesquipedalis were richest in monomeric anthocyanin contents (MAC). Furthermore, the results clearly demonstrated the impact of the plant matrix effect on the preservation of a specific class of phytochemicals. In particular, after cooking and in vitro digestion, total flavonoid contents (TFC) in Glycine max extract was higher than in the uncooked sample. This study is the first report on the influence of cooking and in vitro gastrointestinal digestion on the inhibition capacity toward advanced glycation end products (AGEs). All samples showed a significant capacity to stimulate glucose uptake in yeast model, and V. angularis showed the highest capacity. Interestingly, the increase in glucose uptake after in vitro digestion was higher than in uncooked samples for both P. vulgaris and G. max samples. The current study is the first attempt to investigate at the effects of both processes not only on the natural bioactive compounds but also on antioxidant and anti-diabetic activities of Thailand's 10 most consumed beans that can be applied for agro-industrial and phytopharmaceutical sectors.

Characterization of Bioactive Phenolics and Antioxidant Capacity of Edible Bean Extracts of 50 Fabaceae Populations Grown in Thailand

Fabaceae is the third largest family containing great variation among populations. However, previous studies mainly focus on single species, and phytochemicals at population level have never been reported. This work aims to complete this knowledge with 50 populations from throughout Thailand by (1) determining total phenolic (TPC), flavonoid (TFC), and anthocyanin (TAC) contents; and (2) investigating in vitro and cellular antioxidant potentials. Phytochemicals of 50 populations from different localities are differed, illustrating high heterogeneity occurring in polyphenols accumulations. Vigna unguiculata subsp. sesquipedalis populations showed low variability in TPC ranging from 628.3 to 717.3 mg/100 g DW gallic acid equivalent, whereas the high variability found in TFC and TAC range from 786.9 to 1536.1 mg/100 g DW quercetin equivalent, and 13.4 to 41.6 mg/100 g DW cyanidin equivalent. Red cultivar population #16 had the greatest TAC, but surprisingly the cream cultivars were relatively high in anthocyanins. HPLC quantification of genistein and daidzein showed great variations among populations. In vitro antioxidant results indicated that antioxidant capacity mediated by electron transfer. Cellular antioxidants ranged from 59.7% to 87.9% of ROS/RNS in yeast model. This study investigated at the population level contributing to better and frontier knowledge for nutraceutical/phytopharmaceutical sectors to seek potential raw plant material.

Impact of Germination Time on Resveratrol, Phenolic Acids, and Antioxidant Capacities of Different Varieties of Peanut (Arachis hypogaea Linn.) from China

In China, peanut sprouts are popular among consumers as functional vegetables. This study reports the change in total phenolic content (TPC), total flavonoid content (TFC), monomeric anthocyanin content (MAC), vitamin C, trans-resveratrol content, antioxidant capacities, and phenolic profile of three different varieties of peanut during 8 days of germination. The TPC, TFC, and antioxidant capacity of peanut samples were reduced and then increased with an increase in germination time. TFC values were highly correlated with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) values. MAC values of peanuts were first increased and then decreased during 8 days of germination. The TFC, DPPH, and FRAP values of germinated peanuts were lower compared to the non-germinated peanut. Germination of peanut samples enhanced the total phenolic acids and trans-resveratrol content, but the vitamin C content of peanut sprouts was lower than ungerminated peanuts.