Total Isoflavone Content Research Articles

Avaliação nutricional e aceitação pelo consumidor de extrato de soja de cultivares especiais e convencionais

Abstract The soymilk is a ready-to-eat, nutritious and naturally cholesterol-free product. Several soybean specialty cultivars were developed in Brazil in order to increase the human consumption of soybean products. The aim of this work was to evaluate the nutritional composition and consumer acceptance of soymilk from three soybean cultivars with special features such as high-protein and isoflavone contents, mild flavor and lipoxygenase-free compared to three conventional ones. The soymilk was obtained after blanching with a bicarbonate solution, grinding, centrifugation and pasteurization. The physicochemical and nutritional evaluation data were analyzed using Analysis of Variance (ANOVA) and Tukey’s test to check differences among means, and the consumer data through cluster analysis and internal preference mapping. The lipoxygenases were inactivated after thermal processing. There were significant differences among soybean cultivars and soymilks related to the protein, isoflavones, oil, and sugar contents and soymilk yield (p < 0.05). The BRS 133 and BRS 284 cultivars and soymilks presented the highest total isoflavone content (p < 0.05). Regarding the overall consumer acceptance, there were significant differences among cultivars (p < 0.05) with means ranging from 5.9 to 6.7 and the lower score was obtained by BRS 267. However, the cluster analysis identified three consumer segments according to preference similarity. The cultivars BRS 284 and BRS 267 reached the highest mean among the consumers of segment 1 (6.8 and 6.7 respectively). The consumers of segment 2 preferred the cultivar without lipoxygenases, BRS 213 (mean of 7.5) while segment 3 preferred the BRS 133 (mean of 7.4). The process of blanching of soybean with bicarbonate solution, grinding with boiling water and pasteurization mitigated the differences between conventional and specialty cultivars and the six cultivars evaluated were suitable for soymilk production.

Identification of genes for seed isoflavones based on bulk segregant analysis sequencing in soybean natural population.

We identified four hub genes for isoflavone biosynthesis based on BSA-seq and WGCNA methods and validated that GmIE3-1 positively contribute to isoflavone accumulation in soybean. Soybean isoflavones are secondary metabolites of great interest owing to their beneficial impact on human health. Herein, we profiled the seed isoflavone content by HPLC in 1551 soybean accessions grown in two locations for two years and constructed two extreme pools with high (4065.1µgg-1) and low (1427.23µgg-1) isoflavone contents to identify candidate genes involved in isoflavone biosynthesis pathways using bulk segregant analysis sequencing (BSA-seq) approach. The results showed that the average sequencing depths were 50.3× and 65.7× in high and low pools, respectively. A total of 23,626 polymorphic SNPs and 5299 InDels were detected between both pools and 1492 genes with different variations were identified. Based on differential genes in BSA-seq and weighted gene co-expression network analysis (WGCNA), four hub genes, Glyma.06G290400 (designated as GmIE3-1), Glyma.01G239200, Glyma.01G241500, Glyma.13G256100 were identified, encoding E3 ubiquitin-protein ligase, arm repeat protein interacting with ABF2, zinc metallopeptidase EGY3, and dynamin-related protein 3A, respectively. The allelic variation in GmIE3-1 showed a significant influence on isoflavone accumulation. The virus-induced gene silencing (VIGS) and RNAi hairy root transformation of GmIE3-1 revealed partial suppression of this gene could cause a significant decrease (P < 0.0001) of total isoflavone content, suggesting GmIE3-1 is a positive regulator for isoflavones. The present study demonstrated that the BSA-seq approach combined with WGCNA, VIGS and hairy root transformation can efficiently identify isoflavone candidate genes in soybean natural population.

Association of urinary phytoestrogens with hormone-related cancers and cancer biomarkers: NHANES 1999-2010.

Phytoestrogens may have potential effects on hormone-related cancers (HRC) and cancer biomarkers, but the findings have been inconsistent so far. Participants from the National Health and Nutrition Examination Survey 1999-2010 with information on the levels of urinary phytoestrogens, serum cancer biomarkers and cancer history were included. Sampling-weighted logistic regression models examined the association between urinary phytoestrogens concentrations (creatinine-standardised and log-transformed) and HRC, followed by stratified analyses by race/ethnicity, age and menopausal status for different gender. Correlation analyses between phytoestrogens and cancer biomarkers were performed. Of the total 8844 participants, there were 373 with HRC. We observed total isoflavone and enterodiol excretion were positively associated with HRC, especially in non-Hispanic white female subpopulations (Ptrend < 0·05). Similar association also existed in the total isoflavones and enterodiol levels with breast cancer. Whereas the highest concentration of total isoflavones was significantly linked to a reduced prevalence of HRC (OR = 0·40, 95 % CI: 0·19, 0·84) in white males and of prostate cancer (OR = 0·40, 95 % CI: 0·18, 0·86). Among twenty-four participants with HRC, urinary equol concentration was positively correlated with CA15.3. Also, an inverse correlation of total prostate-specific antigens (PSA) and positive correlation of the PSA ratio with urinary enterolactone were detected in thirteen prostate cancer patients. Our findings indicated that higher concentrations of total isoflavones and enterodiol were positively associated with HRC. Urinary certain phytoestrogen excretion may affect serum cancer biomarker levels in cancer patients. But further prospective studies are needed to provide stronger evidence.

FERMENTATION OF SOYBEAN SEEDS USING RHIZOPUS OLIGOSPORUS FOR TEMPEH PRODUCTION AND STANDARDIZATION BASED ON ISOFLAVONES CONTENT

Objective: To determine the best temperature and time of fermentation for making soybean (Glycine max (L.) Merril) tempeh seeds with high content of isoflavones. Methods: Five varieties of soybean seeds, Devon-1, Dena-1, Dega-1, Anjasmoro, and Argomulyo, were determined for their isoflavones content using an Ultraviolet (UV) spectrophotometer. A variety containing the highest isoflavones was washed, boiled, peeled, then mixed with tempeh starter (Rhizopus oligosporus culture) at 1 g/kg. The mixture was then poured into plastic bags and flattened with two centimeters of thickness. Fermentation in three conditions: (a) ambient temperature (27-32 °C) without air circulation, (b) 27±0.5 °C, and (c) 30±0.5 °C both with air circulation. The inner temperature, ripening time, and rotting time was recorded. The total isoflavones content was measured every 6 h. Results: The variety of Devon-1 has the highest content of isoflavones (0.112% w/w). Fermentation in condition (a) caused the tempeh too hot(42 °C) and rotted at the 42nd h. Condition (b) produced the best tempeh, ripening at the inner peak temperature (32.5 °C) at the 32nd h; and rotted after the 100th h. Condition (c) produced good tempeh; the ripening occurred at the 31st h at 33 °C and rotted after the 113th h. Tempeh that was produced with condition (b) at the 72nd h has the highest content of isoflavones (0.089% w/w). Conclusion: Fermentation at 27±0.5 °C with air circulation for 72 h produced tempeh with the highest isoflavones content (0.089% w/w), but decrease about 20% compared to its content in seeds (0.112% w/w).

Comprehensive review of composition distribution and advances in profiling of phenolic compounds in oilseeds.

A wide range of phenolic compounds participate in oilseed growth, regulate oxidative stability of corresponding vegetable oil, and serve as important minor food components with health-promoting effects. Composition distribution of phenolic compounds varied in oilseeds. Isoflavones, sinapic acid derivatives, catechin and epicatechin, phenolic alcohols, chlorogenic acid, and lignans were the main phenolic compounds in soybean, rapeseed, peanut skin, olive, sunflower seed, sesame and flaxseed, respectively. Among which, the total isoflavones content in soybean seeds reached from 1,431 to 2,130 mg/100 g; the main phenolic compound in rapeseed was sinapine, representing 70-90%; chlorogenic acid as the predominant phenolic compound in sunflower kernels, represented around 77% of the total phenolic content. With the rapid development of analytical techniques, it is becoming possible for the comprehensive profiling of these phenolic compounds from oilseeds. This review aims to provide recently developments about the composition distribution of phenolic compounds in common oilseeds, advanced technologies for profiling of phenolic compounds by the metabolomics approaches based on mass spectrometry. As there is still limited research focused on the comprehensive extraction and determination of phenolics with different bound-forms, future efforts should take into account the non-targeted, pseudo-targeted, and spatial metabolomic profiling of phenolic compounds, and the construction of phenolic compound database for identifying and quantifying new types of phenolic compounds in oilseeds and their derived products.

Changes of γ-Aminobutyric Acid, Phytoestrogens, and Biofunctional Properties of the Isoflavone-Enriched Soybean (Glycine max) Leaves during Solid Lactic Acid Fermentation

The present study documents the changes in the γ-aminobutyric acid (GABA), the total phenolic (TP), total flavonoid (TF), and isoflavone contents, the antioxidant activities and the digestive enzyme inhibition during the solid lactic acid fermentation of isoflavone-enriched soybean leaves (IESLs) with starters Lactiplantibacillus plantarum P1201 and Levilactobacillus brevis BMK184. The contents of glutamic acid (GA) and GABA remained almost unchanged during fermentation with P1201. In contrast, the contents of GABA increased from 144.24 to 173.09 and 175.59 mg/100 g, and the contents of GA decreased from 43.68 to 18.26 and 11.25 mg/100 g during the IESLs’ fermentation with BMK184 and the combined use of P1201 + BMK184, respectively. The total isoflavone content decreased during fermentation, but the isoflavone aglycone levels increased; in fact, the levels of daidzein and genistein were the highest after the use of P1201 + BMK184 (2265.57 μg/g) and BMK184 (1055.27 μg/g), respectively, at 72 h of fermentation. Correspondingly, the DPPH (90.90%), the ABTS (91.09%), and the hydroxyl (74.88%) radical scavenging activities, the ferric reducing/antioxidant power (2.45), as well as the α-glucosidase (49.86%) and pancreatic lipase (37.30%) inhibition activities exhibited their highest levels after fragmentation with P1201 + BMK184.

Co-Fermentation of Edible Mushroom By-Products with Soybeans Enhances Nutritional Values, Isoflavone Aglycones, and Antioxidant Capacity of Douchi Koji

Douchi is a traditional salt-fermented soybean food with various bioactivities, such as anti-oxidation, anti-diabetes, and anti-hypertension, which are greatly affected by the activities of protease and β-glucosidase during koji production. Edible mushroom by-products are ideal ingredients for enhancing food flavor and nutritional quality due to their unique nutritional characteristics of high protein, rich amino acids, and low calories. However, there is no research on the preparation of Douchi by the mixed fermentation of edible mushroom by-products and soybeans. In this study, response surface methodology (RSM) was used to optimize the fermentation conditions of edible mushroom by-product Douchi koji (EMDK) with protease and β-glucosidase activities as indicators, and the changes in the main bioactive compounds and antioxidant activities of unfermented raw samples (URS), Douchi koji without edible mushroom by-product (DKWE), and EMDK were compared. The results of single-factor tests and RSM showed that the optimal fermentation conditions of EMDK were the Aspergillus oryzae to Mucor racemosus ratio of 1:1, inoculation amount of 6%, edible mushroom amount of 21%, and fermentation time of 63 h, and the activities of protease and β-glucosidase under these conditions were 796.03 ± 15.01 U/g and 1175.40 ± 36.98 U/g, respectively. Additionally, compared with URS and DKWE, the contents of total isoflavones and β-glucoside isoflavones in EMDK were notably decreased, while the contents of amino nitrogen, total phenolics, total flavonoids, and aglycone isoflavone, as well as the antioxidant capacity were significantly increased. Furthermore, significant correlations were found between the above components and antioxidant capacity. These results showed that edible mushroom by-product could be incorporated into soybeans for co-fermentation, conferring higher nutritional value to and antioxidant capacity of Douchi koji.

Effect of cold plasma on physical–biochemical properties and nutritional components of soybean sprouts

Cold plasma has been used to promote seed germination. In this study, soybean seeds were directly treated with cold plasma (CP) for different durations (0, 30, 60, 120, and 180 s) and then cultivated with cold-plasma-activated water (PAW) during germination. The effects of CP and PAW treatment on the physical–biochemical properties and nutritional components of soybean sprouts were investigated. The results showed that sprout length increased by 41.07% after moderate CP (60 s) and further increased with PAW. The fresh weight increased by 11.24% after moderate CP treatment. Although sugar content decreased with CP, it increased with PAW. Total amino acid and isoflavone content increased after moderate CP treatment. Both CP and PAW treatments increased the intercellular water and weakened the fluidity of water, and small-molecule proteins were polymerized into large-molecule proteins. The solubility of protein was enhanced under PAW treatment. However, neither PAW nor CP treatment exerted a significant influence on the secondary structure of proteins. The hardness of the soybean sprouts decreased and their fracturability increased after moderate CP treatment. This study demonstrates that cold plasma has the potential to enhance the biomass and edible quality of soybean sprouts.

Determination of 14 Isoflavone Isomers in Natto by UPLC-ESI-MS/MS and Antioxidation and Antiglycation Profiles.

Natto is a famous traditional fermented food, but the influence of the fermentation process on the content and composition of soybean isoflavones and nutritional value is still unclear. In the present study, the variation in soybean isoflavones during fermentation by Bacillus subtilis natto was revealed by UPLC-ESI-MS/MS (Ultra high performance liquid chromatography-electron spray ionization-mass spectrometry) analysis. After 24 h of fermentation, the total isoflavone content in natto increased by 1.62 times compared with fresh soybean, and the content of aglycones was 3.07 times that of raw beans. More importantly, among 14 isoflavone isomers identified in natto, the isomers of daidzin, genistin, and succinyl genistin were detected for the first time, which might be due to the result of isomerase and succinylase and other corresponding enzymes’ action in Bacillus subtilis. In addition, natto isoflavones performed great antioxidant activity than its monomer components (glycosides daidzin and genistin, aglycones genistein and daidzein), except for genistein. Moreover, natto isoflavone and its aglycones (especially genistein) performed great inhibitory activity against AGEs (Advanced Glycation End Products) in three in vitro models. The mechanism test showed that genistein could form adducts (UPLC-Q-TOF-ESI-MS/MS analysis) with methylglyoxal. These findings demonstrated that soybean fermented with Bacillus subtilis natto had a significant influence on the isoflavone profiles and its bioactivity.

Optimizing pre-treatment of alkaline hydrolysis RP-HPLC for enhancing accuracy of soy isoflavone determination

Isoflavones (IFs) are important bioactive compounds which offers several benefits to human health. Despite the importance of IFs content, there are still some deficiencies in the existing methods. The objective of this study is to optimize key parameters of alkaline hydrolysis method for enhancing both reliability and accuracy of quantitative analysis of IFs contents in soybeans and soy protein products. Solvent type, extraction temperature, heating mode, alkaline concentration, hydrolysis temperature, hydrolysis time and some details are key points to target analytes which yield determining parameters. The biggest IFs content was obtained by extraction using methanol (MeOH)/water (80:20, v/v) in a 75 ℃ oven for 2 h, and hydrolyzation with 3 M NaOH solution at a room temperature for 10 mins. The total IFs content obtained by the improved method has increased by 16.4% compared with AOAC Official Method 2001.10. The accuracy of the method was evaluated using the relative standard deviation (RSD). Intraday accuracies in the total amount of isoflavones of four samples were 0.03%-0.63% (n = 3). Interday accuracy in the total amount of isoflavones was 2.71% (n = 6). LOD of IFs ranged from 0.1μg/mL for aglycones to 0.2μg/mL for glucosides. LOQ of IFs ranged from 0.3μg/mL for aglycones to 0.5μg/mL for glucosides. The improved method was proven to be a more accurate way to determine IFs contents in soybeans and soy protein products and thus making it useful for quality control and systematic in-depth study of soybeans and soy products; even to further assess the dietary soy exposure and the soy-health association.

Phytochemical screening and properties of botanical crude extracts and ethyl acetate fractions isolated by deep eutectic solvent

Botanicals, being safe because of their natural origin, are associated with potential health benefits due to their isoflavones-rich content. Isoflavones as plant-generated secondary metabolites are formed to defend against environmental stress such as UV radiation, mechanical damage, or any other attack from the surroundings. Kudzu (Pueraria roots and flowers), red clover (Trifolium pratense), and soy (Glycine max) are of significant importance in the medical field. Isoflavones were reported to exhibit a variety of biological functions, e.g., antiaging, anticancer, and microbiome modulations. This study focuses attention on the extraction and quantification of isoflavones from kudzu roots (KR), kudzu flowers (KF), red clover (RC), and soy molasses (SM), and determining their total polyphenols (TPC), flavonoids (TFC), and antioxidant activity (AOA). Novel green ultrasound-assisted extraction (UAE) technology was developed to extract and quantify the isoflavones. The results showed the quantity of isoflavones in KR, KF, RC, and SM crude extracts to be 1.01%, 2.9%, 0.70% and 0.67%, respectively. The fractionation using ethyl acetate (EA) improved the yield that became 1.48%, 2.5%, 1.3% and 0.89% in the KR, RC and SM extract fractions, respectively. This investigation eventually showed that our green UAE methodology is a safe and efficient method for recovering isoflavones. The total isoflavone contents were recorded as follows: KFKRRCSM. We concluded that these botanicals are a crucial source of isoflavones that exhibit strong antioxidant properties.

In Vitro Evaluation of the Antioxidant Activity and Chemopreventive Potential in Human Breast Cancer Cell Lines of the Standardized Extract Obtained from the Aerial Parts of Zigzag Clover (Trifolium medium L.).

The aboveground parts of Trifolium medium L. (zigzag clover), a little-known representative of the family Fabaceae, collected during flowering in a wild stand (Sławin-Szerokie district, Lublin, Poland), were used in this study. Our previous investigations confirmed the higher content of phytoestrogenic isoflavones (especially biochanin A and formononetin derivatives) in T. medium compared to the closely related medicinal plant T. pratense (red clover) and the involvement of these compounds in anti-osteoporotic effects in ovariectomized female rats. The current study focused on evaluating other antibiodegenerative (antioxidant, chemopreventive, and cytostatic) effects for the lyophilisate (TML) obtained from wild zigzag clover. For this purpose, efficient ultrasound-assisted extraction (UAE) was employed, followed by vacuum drying and phytochemical standardization using a newly developed reversed-phase high-performance liquid chromatography (RP-LC) coupled with a PDA detection. Malonylglycosides of biochanin A and formononetin were the predominant compounds and were found to contribute more than 54% to the total isoflavone content determined in the standardized extract of zigzag clover. The antioxidant potential of TML was examined in vitro using the Folin–Ciocalteu and cupric ion-reducing (CUPRAC) methods in addition to the free radical (DPPH• and ABTS•+) scavenging assays. The cytotoxic effects of TML, formononetin, and ononin were evaluated on MCF-7 (estrogen-dependent) and MDA-MB-231 (estrogen-independent) human breast cancer cell lines using the MTT assay. The important role of malonyl isoflavone derivatives has been indicated both in chemoprevention and potential cytotoxic effects of TML against certain types of breast cancer.

Occurrence of isoflavones in soybean sprouts and strategies to enhance their content: A review.

Sprouting is a common strategy to enhance the nutritional value of seeds. Here, all the reports regarding the occurrence of isoflavones in soybean sprouts have been covered for the first time. Isoflavones were detected with concentrations ranging from 1 × 10-2 to 1 × 101 g/kg in soybean sprouts. Isoflavone concentration depends on the cultivar, germination time, part of the sprout, light, and temperature. Aglycon isoflavones increased during germination, especially in the hypocotyl, while 6″-O-malonyl-7-O-β-glucoside isoflavones decreased in the hypocotyl and increased in the cotyledon and root. Cooking reduced total isoflavone content. Regarding the strategies to enhance isoflavone contents, fermentation with Aspergillus sojae and external irradiation with UV-A or far-infrared were the methods that caused the greatest increases in aglycon, 7-O-β-glucoside, and total isoflavones. However, the largest increases in 6″-O-malonyl-7-O-β-glucoside and 6″-O-acetyl-7-O-β-glucosides isoflavones were detected after treatment with chitohexaose and calcium chloride, respectively. PRACTICAL APPLICATION: Soybean sprouts are widely consumed and provide essential proteins, antioxidants, and minerals. They are rich in isoflavones, which exhibit numerous health benefits, and have been studied as alternative therapies for a range of hormone-dependent conditions, such as cancer, menopausal symptoms, cardiovascular disease, and osteoporosis. Despite numerous reports being published to date regarding the occurrence of isoflavones in soybean sprouts, the publications in this field are highly dispersed, and a review has not yet been published. This review aims to (1) highlight the particular isoflavones that have been detected in soybean sprouts and their concentrations, (2) compared the effects of temperature, light, cooking and soybean cultivar affect the isoflavone levels on the different parts of the sprout, and (3) discuss the efficacy of the methods to enhance isoflavone contents. This review will provide a better understanding of the current state of this field of research by comparing the general trends and the different treatments for soybean sprouts.

Impact of Pulsed Electric Field Pre-Treatment on the Isoflavone Profile of Soymilk

In this study, pulsed electric fields (PEFs) were evaluated as extraction-aiding technology during soymilk manufacturing to improve its isoflavone profile. Low-intensity PEFs were applied at different processing conditions in two stages of the soymilk extraction process, hydrated soybeans (HSB) and soybean slurry (SBS), with the soymilk extracted from the conventional process as control (CSM). Overall, resultant soymilk samples from PEF-HSB and PEF-SBS presented lower concentrations of glucosides isoflavones and greater aglycone content than those in CSM. In contrast to genistin (Gin) and daidzin (Din), which decreased around 18.5–52.6% and 10.9–54.6%, respectively, an increase in genistein (Ge, 12.3–64.4%) and daidzein (Da, 9–55.8%) was observed. The total isoflavone content (TIC) of most soymilk samples prepared from PEF-HSB was lower than that of the CSM. Conversely, when PEF-SBS was used, the TIC of resultant soymilk was not significantly affected or slightly decreased. However, PEF treated HSB at 10 kVcm−1/100 pulses and SBS at 6 kVcm−1/10 pulses led to a significant augment in TIC, of up to 109 ± 2.39 and 110 ± 1.26 μg/g, respectively, in the extracted soymilk samples. These results indicated that low-intensity PEF is a potential technology that could be implemented during soymilk manufacturing processing to modify the isoflavone profile and content of soymilk, mainly increasing its aglycone concentration.

Origin and seed coat color differently affect the concentrations of metabolites and antioxidant activities in soybean (Glycine max (L.) Merrill) seeds

In this study, 54 soybean germplasms of different seed coat colors originated from America, China, Japan, and Korea were cultivated in Korea and analyzed for the contents of total oil, total protein, total phenolic, five fatty acids, and five isoflavones, and antioxidant activities using three assays. The soybeans showed significant variations (p < 0.05) of metabolite contents and antioxidant activities. Origin and seed coat color exhibited a slight or insignificant effect on total protein and total oil contents. In contrast, origin and seed coat color significantly affected the concentration of individual and total isoflavones, and total phenolics, with few exceptions. Whereas fatty acids were significantly affected by origin, seed coat color provided better information regarding the variations in antioxidant capacities. Together, multivariate and correlation analyses revealed important associations between biosynthetically-related metabolites. In general, origin and seed coat color differently influenced the concentration of different classes of metabolites and antioxidant activities.

The Influence of the Parameters of the Subcritical Water Extraction Process on the Efficiency of Isoflavones Elicitation from Soy Meal

Topicality. Incidental products of soy processing (okara, meal, millcake) contain a large amount of protein, and, additionally, other valuable biologically active substances. Among them, isoflavones are of particular researchers’ interest. Subcritical water extraction is a promising method for elicitation biologically active substances from plant raw material. However, such a method of extracting isoflavones, and its rational parameters for soy meal, remain insufficiently investigated. Aim and methods. The aim of this work is to study the influence of parameters (temperature: 120...160°С, duration of extraction: 5...15 min, hydromodule: 1:15...25) of the extracting process of soy meal with subcritical water on the isoflavones content in the dry material of the extract. The empirical research method is applied, using the second-order orthogonal compositional outline for a fractional factor experiment. The samples of soy meal extract are obtained using the experimental setup, based on the high-pressure reactor “RHP-2-500”. The total isoflavones content in the dry extract material is defined in terms of gallic acid with absorption spectrophotometry method. Results. Based on the obtained results, the quadratic interpolation model is constructed. This model links the total isoflavones content in the dry extract material with the extraction parameters. The analysis of the constructed model makes it possible to establish rational measures of extraction parameters. Conclusions and discussion. In this study, the intensive growth of soflavones content in the dry extract with highing the temperature process, and a relatively small influence of the process duration on this indicator, were defined. The influence of the hydromodule is ambiguous. The lowest yield of isoflavones is noted at hydromodule ≈1:21,41. Its increase or decrease lead to the growth of isoflavones content in the extract. In this paper, for the first time, the existence of rational measures of parameters in the process of extracting isoflavones with subcritical water from soy meal is studied and established. The obtained results can be used in the elaboration of the technology for producing isoflavones enriched soy protein concentrate.

Nutritional evaluation and transcriptome analyses of short-time germinated seeds in soybean (Glycine max L. Merri.)

Germination is a common practice for nutrition improvement in many crops. In soybean, the nutrient value and genome-wide gene expression pattern of whole seeds germinated for short-time has not been fully investigated. In this study, protein content (PC), water soluble protein content (WSPC), isoflavone compositions were evaluated at 0 and 36 h after germination (HAG), respectively. The results showed that at 36HAG, PC was slightly decreased (P > 0.05) in ZD41, J58 and JHD, WSPC and free isoflavone (aglycones: daidzein, genistein, and glycitein) were significantly increased (P < 0.05), while total isoflavone content was unchanged. Transcriptomic analysis identified 5240, 6840 and 15,766 DEGs in different time point comparisons, respectively. GO and KEGG analysis showed that photosynthesis process was significantly activated from 18HAG, and alternative splicing might play an important role during germination in a complex manner. Response to hydrogen peroxide (H2O2) was found to be down regulated significantly from 18 to 36HAG, suggesting that H2O2 might play an important role in germination. Expression pattern analysis showed the synthesis of storage proteins was slowing down, while the genes coding for protein degradation (peptidase and protease) were up regulated as time went by during germination. For genes involved in isoflavone metabolism pathway, UGT (7-O-glucosyltransferase) coding genes were significantly up regulated (40 up-DEGs vs 27 down-DEGs), while MAT (7-O-glucoside-6′′-O-malonyltransferase) coding genes were down regulated, which might explain the increase of aglycones after germination. This study provided a universal transcriptomic atlas for whole soybean seeds germination in terms of nutrition and gene regulation mechanism.

The Soybean High Density 'Forrest' by 'Williams 82' SNP-Based Genetic Linkage Map Identifies QTL and Candidate Genes for Seed Isoflavone Content.

Isoflavones are secondary metabolites that are abundant in soybean and other legume seeds providing health and nutrition benefits for both humans and animals. The objectives of this study were to construct a single nucleotide polymorphism (SNP)-based genetic linkage map using the ‘Forrest’ by ‘Williams 82’ (F×W82) recombinant inbred line (RIL) population (n = 306); map quantitative trait loci (QTL) for seed daidzein, genistein, glycitein, and total isoflavone contents in two environments over two years (NC-2018 and IL-2020); identify candidate genes for seed isoflavone. The FXW82 SNP-based map was composed of 2075 SNPs and covered 4029.9 cM. A total of 27 QTL that control various seed isoflavone traits have been identified and mapped on chromosomes (Chrs.) 2, 4, 5, 6, 10, 12, 15, 19, and 20 in both NC-2018 (13 QTL) and IL-2020 (14 QTL). The six QTL regions on Chrs. 2, 4, 5, 12, 15, and 19 are novel regions while the other 21 QTL have been identified by other studies using different biparental mapping populations or genome-wide association studies (GWAS). A total of 130 candidate genes involved in isoflavone biosynthetic pathways have been identified on all 20 Chrs. And among them 16 have been identified and located within or close to the QTL identified in this study. Moreover, transcripts from four genes (Glyma.10G058200, Glyma.06G143000, Glyma.06G137100, and Glyma.06G137300) were highly abundant in Forrest and Williams 82 seeds. The identified QTL and four candidate genes will be useful in breeding programs to develop soybean cultivars with high beneficial isoflavone contents.

Bioactive compounds, biological activity, and starch digestibility of dried soy residues from the soybean oil industry and the effects of hot-air drying.

Soybean residue is a by-product from the soy industry. It is rich in protein, lipids, carbohydrates, and bioactive compounds but it is still underutilized as a food ingredient. The aim of the present study was to investigate the bioactive components, biological activity, and starch digestibility of soybean residues collected from the soybean oil industry (SOI) and the laboratory (SOL), and the effects of hot-air drying on the treated residues. The predominant phenolic acids were protocatechuic, chlorogenic, and ferulic acids, and the major flavonoids were rutin, daidzein, and genistein. After hot-air drying, the total phenolic, flavonoid, and isoflavone content of dried SOI and SOL increased significantly, in comparison with untreated whole soybean (WSB), SOI, and SOL. Daidzein of dried SOI and SOL increased from 63 to 510 mg kg-1 dry weight. The 2,2-diphenyl-1-picryldrazyl (DPPH) and ferric reducing antioxidant power (FRAP) values increased almost twofold in comparison with SOI and SOL. The antioxidant compounds in untreated and treated soy-residue extracts were the most efficient in inhibiting α-amylase. The phenolics and flavonoids caused starch digestion to reduce from 6.6% to 2.7%. The correlations, involving phenolic compounds (including phenolics, flavonoids, and isoflavones), demonstrated that the different phenolic extracts showed different antioxidant properties, which played an important role in soy oil-residue phenolic fractions. We suggest that soy oil residues could be used as ingredients in functional foods because of their health-promoting attributes. © 2021 Society of Chemical Industry.

Nitric oxide mediates γ-aminobutyric acid signaling to regulate phenolic compounds biosynthesis in soybean sprouts under NaCl stress

Salt stress is an effective way to enhance the accumulation of phenolic compounds in soybean sprouts. In the present study, the effects of nitric oxide (NO) and γ-aminobutyric acid (GABA) on the biosynthesis of phenolic compounds in soybean sprouts under NaCl stress were investigated. Results showed that activities of three key enzymes involved in the biosynthesis of phenolic compounds increased by 27%–55% when the exogenous donor of NO was applied. As a result, the concentration of total phenolic compounds, phenolic acids and isoflavones in sprouts under NaCl stress increased by 26.64%, 10.91% and 19.14%, respectively. In addition, both N-nitro-L-arginine methyl ester (L-NAME) and sodium tungstate treatment inhibited the synthesis of NO in soybean sprouts under NaCl stress, which lead to the decrease of phenolics content. Treatment of GABA can alleviate the inhibition of L-NAME on phenolics biosynthesis by enhancing the production of NO. On the other hand, NO treatment can also alleviate the inhibition of 3-mercaptopropionic acid, the inhibitor of GABA synthesis, on the biosynthesis of phenolic compounds. To conclude, both NO and GABA can enhance the biosynthesis of phenolic compounds in soybean sprouts and NO can mediate the promoting effect of GABA.