Comparison of nutritional components (isoflavone, protein, oil, and fatty acid) and antioxidant properties at the growth stage of different parts of soybean [Glycine max (L.) Merrill]

Abstract

This is the first study to investigate antioxidant capacities of isoflavones prepared using microwave-assisted hydrolysis method from different parts (seeds, leaves, leafstalks, pods, stems and roots) of soybean at growth stages. In addition, the fluctuations in the isoflavone, protein, fatty acid, and oil contents in R6-R8 (R6: beginning; R7: beginning maturity; R8: full maturity) seeds were confirmed. The R7 seeds exhibited the most predominant contents of isoflavones (1218.1±7.3 μg/g) in the following order: daidzein (48%)>genistein (35%)>glycitein (17%). The second highest isoflavone content was found in the leaves (1052.1±10.4 μg/g), followed by R8 seeds>roots>R6 seeds>leafstalks> pods; the stems exhibited the lowest isoflavone content (57.2±1.7 μg/g). Interestingly, daidzein showed the highest individual isoflavone content with remarkable variations (57.2-766.8 μg/g), representing 46-100% of the total isoflavone content. R8 exhibited higher protein, fatty acid, and oil contents than R6 or R7. Moreover, the antioxidant capacities against two radicals in different parts of soybean plant showed considerable differences depending upon the isoflavone content. Our results suggested that soybean leaves and seeds might be useful materials for functional foods.

Phenolic Composition and Antioxidant Activities of Soybean (Glycine max (L.) Merr.) Plant during Growth Cycle

“…In our study, the highest content of isoflavones was observed at vegetative stages (Table 3). In the study of Seao et al [49] the highest contents of individual isoflavones (daidzein, glycitein, genistein, and genistein) in seeds at the growth period of beginning maturity were higher than those at the growth period of beginning full seed and full maturity. At the beginning of maturity, the soybean seeds showed the stronger antioxidant potential than at the growth period of beginning full seed and full maturity [49].…”

Metabolomics as a Tool to Study Underused Soy Parts: In Search of Bioactive Compounds

“…In addition to the four main causes of change in soy metabolism mentioned above, both qualitative and quantitative metabolic variations among soy organs are expected. To present an overview of the metabolite profile of underused soy parts, we selected metabolomics and related works which used various approaches to analyze them [38,67,[78][79][80]93,94,[98][99][100][101][102][103][104][105][106][107][108]. Using Jchem (JChem for Excel 21.1.0.787, ChemAxon (https://www.chemaxon.com accessed on 8 April 2021)) [109] and ClassyFire [110], we organized and classified the metabolites identified in soy roots, leaves, branches, and pods, as presented in Supplementary Materials Table S1-S4, respectively.…”

“…Leaves and roots are the most-studied underused soy parts. In Table S2, 259 metabolites of 32 classes identified in soy leaves are presented [38,78,80,94,98,[101][102][103]106]. Almost 90 of these compounds are flavonoids, isoflavonoids, or prenol lipids.…”

Enhanced biotransformation of soybean isoflavone from glycosides to aglycones using solid‐state fermentation of soybean with effective microorganisms (EM) strains

“…Although aglycone isoflavones in total SIF have lower amounts, they have higher biological activity in the intestine than that of their glycosidic isoflavones (Izumi, Piskula, Osawa, Obata, & Tob, 2000). Therefore, SIF must be transformed to be absorbed or utilized bioactive compounds by acid hydrolysis (Nemitz et al, 2017;Seo et al, 2017), enzyme treatment (Ahn-Jarvis, Teegarden, Schwartz, Lee, & Vodovotz, 2017), or microbial fermentation (Gaya, Peirotén, Álvarez, Medina, & Landete, 2018), because it cannot be synthesized in human body. However, acid hydrolysis methods have many disadvantages including low yields, acute reaction conditions and being harmful to human health, thus, cannot be used in large-scale applications.…”