Antioxidant capacity, phenolics and isoflavones in soybean by-products

Different solvent fractions of Acanthopanax senticosus harms exert antioxidant and anti-inflammatory activities and inhibit the human Kv1.3 channel

The potential antioxidant and anti-inflammatory activities of Acanthopanax senticosus Harms were evaluated and its effect on the human Kv1.3 potassium channel was detected. The ethyl acetate fraction possessed the highest phenolic (289.19±7.43 mg tannic acid equivalents/g) and flavonoid (10.80±0.67 mg quercetin equivalents/g) contents and exhibited stronger antioxidant effects than other fractions in most of the antioxidant assays. On the other hand, the dichloromethane (CH(2)Cl(2)) fraction showed the strongest anti-inflammatory activity. The CH(2)Cl(2) fraction inhibited the expression of inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-α and interleukin 1β mRNAs, and the generation of reactive oxygen species in lipopolysaccharide-induced RAW 264.7 cells. Also, the peak current was inhibited 54.8%±17% by the CH(2)Cl(2) fraction in voltage-clamp recording from Xenopus laevis oocytes. Our research demonstrated that fractions of A. senticosus have great potential to be a source of edible antioxidant and anti-inflammatory agents.

Mineral elements, lipoxygenase activity, and antioxidant capacity of okara as a byproduct in hydrothermal processing of soy milk

Minerals and antioxidative capacity of raw okara that was obtained as a byproduct from six soybean varieties during hydrothermal cooking (HTC) of soy milk were assessed. Lipoxygenase (Lox), an enzyme deteriorating the sensory characteristics of okara, was also investigated. All genotypes had very similar concentrations of Lox (4.32-5.62%). Compared to raw soybeans, the applied HTC significantly reduced Lox content in okara (0.54-0.19%) and lowered its activity to 0.004-0.007 μmol g(-1) min (-1). Correlation between the content of Lox in soybeans and that in okara (r = 0.21;p < 0.05) was not registered. This indicates that the content of this enzyme in okara depended much more on the technological process than on soybean genotype. Very strong correlation (r = 0.99; p < 0.05) between okara Lox content and its activity was found. The most abundant minerals in raw okara were potassium (1.04-1.21 g/100g), phosphorus (0.45-0.50 g/100 g), calcium (0.26-0.39 g/100 g), and iron (5.45-10.95 mg/100 g). A very high antioxidant capacity (19.06-29.36 mmol Trolox kg(-1)) contributes to the nutritional value of raw okara.

Soybean Curd Residue: Composition, Utilization, and Related Limiting Factors

The production of soybean products has been increasing throughout the world, and there has been a corresponding increase in the quantity of soybean curd residue (SCR) being thrown out. The dumping of SCR has become a problem to be solved due to its contamination to the environment. SCR is rich in fiber, fat, protein, vitamins, and trace elements. It has potential for value-added processing and utilization; options that simultaneously hold the promise of increased economic benefit as well as decreased pollution potential for the environment. The objective of this study is to fully investigate, review, and summarize the existing literature in order to develop a comprehensive knowledge base for the composition and reuse of SCR. It is evident from the literature survey that SCR shows good potential as a functional food material. However, there are several drawbacks to the use of SCR and corresponding solutions presented in this paper.

Quantitative analysis of polyphenols and antioxidant activity in four Daphne L. species

The content of biologically active phenolic compounds (total polyphenols, tannins, flavonoids, and phenolic acids) were determined using spectrophotometry in four wild Croatian species of Daphne L. in the family Thymelaeaceae (Daphne alpina, D. cneorum, D. laureola, and D. mezereum). The concentration of total flavonoids (TF) was highest in the leaves of these Daphne species (0.12–0.51% dry herb weight, DW) whereas the content of other phenolic compounds analyzed were highest in the roots, including total polyphenols (TP; 2.71–19.03% DW), tannins (T; 1.14–7.39% DW), and total phenolic acids (TPA; 0.12–0.87% DW). D. alpina contained the highest amount of polyphenols, with the exception of flavonoids, where maximum concentrations were found in D. laureola. We also examined the antioxidant activity of leaf, stem, and root extracts. All extracts analyzed demonstrated high free radical scavenging activity with the highest concentration in the leaf extracts of D. alpina. Leaf extracts of D. cneorum showed the highest antioxidant activity in a β-carotene bleaching assay.

Soymilk phenolic compounds, isoflavones and antioxidant activity as affected by in vitro gastrointestinal digestion

The aim of this research was to evaluate changes in the phenolic compounds, isoflavones and antioxidant activity of soymilk following in vitro gastrointestinal digestion (including dialysis). Gastric digestion significantly influenced the release of bioactive substances from the soymilk matrix, increasing the concentration of total phenolic components (35% as the sum of individuals and 14% by Folin-Ciocalteu [F-C] method), total isoflavone content (22%) and total antioxidant activity (76%). The concentration of all those compounds was reduced significantly in the duodenal fraction in comparison to gastric digestion and their lowest concentration was observed in the dialysed fraction, where phenolic acids were not detected. The bioaccessibility of soymilk phenolic compounds was 15% as the sum of individuals and 20% by F-C assay; isoflavones 36% and constituents with antioxidant activity 27%. Results suggest that most of these compounds were sufficiently available to be absorbed and could contribute health benefits.

Analysis of isoflavone, phenolic, soyasapogenol, and tocopherol compounds in soybean [ Glycine max (L.) Merrill] germplasms of different seed weights and origins

This study investigated the functional compounds, including isoflavones, phenolics, soyasapogenols, and tocopherols, that were detected in 204 soybean [ Glycine max (L.) Merrill] germplasms. The soybean samples were divided into three groups according to origin: America, China, and Korea. The soybean samples were also classified into three groups on the basis of 100-seed weight: small (<13 g), medium (13-24 g), and large (>24 g). Among the soybean germplasms, CSRV121 (Bosukkong) had the highest level of isoflavone content (4778.1 μg g(-1)), whereas CS01316 had the lowest isoflavone content (682.4 μg g(-1)). Of the soybeans from the three different countries of origin, those from Korea showed the highest average concentration of total isoflavones (2252.6 μg g(-1)). The small seeds had the highest average total isoflavone concentration (2520.0 μg g(-1)) of the three different seed sizes. Among the 204 soybean germplasms, CS01405 had the highest content of total phenolics (5219.6 μg g(-1)), and CSRV017 (Hwangkeumkong) had the lowest phenolic content (654.6 μg g(-1)). The mean concentrations of total phenolic compounds were 2729.1 μg g(-1) in American soybean seeds, 1680.4 μg g(-1) in Chinese soybean seeds, and 1977.6 μg g(-1) in Korean soybean seeds. Of the soybean seeds from the three different countries of origin, American soybean seeds had the highest average concentration of total phenolic compounds, and Korean varieties showed the second highest value. Small soybean seeds had the highest average content of total phenolic compounds (2241.7 μg g(-1)), whereas medium-sized (1926.8 μg g(-1)) and large (1949.9 μg g(-1)) soybeans had lower concentrations of phenolic compounds. In whole soybean germplasms, the level of total soyasapogenols was higher in CS01173 (1802.3 μg g(-1)) and CS01346 (1736.8 μg g(-1)) than in the other types of soybeans. The mean concentrations of total soyasapogenol were 1234.0 μg g(-1) in American, 1294.5 μg g(-1) in Chinese, and 1241.5 μg g(-1) in Korean soybean varieties. Chinese soybean varieties showed the highest mean concentration of total soyasapogenol, and Korean soybean seeds showed the second highest level. The medium-seed group had the highest soyasapogenol content (1269.3 μg g(-1)) of the seeds that were grouped by size. A larger amount of soyasapogenol B than soyasapogenol A was detected. In whole soybeans, CS01202 showed the highest level of total tocopherols (330.5 μg g(-1)), whereas CSRV056 (Pungsannamulkong) had the lowest content (153.3 μg g(-1)). Chinese soybeans had the highest average concentration of total tocopherols (255.1 μg g(-1)). By comparison, the medium-sized Chinese soybean group had the highest (256.1 μg g(-1)) average total tocopherol content.

Separation of soybean isoflavone aglycone homologues by ionic liquid-based extraction

The separation of a compound of interest from its structurally similar homologues is an important and challenging problem in producing high-purity natural products, such as the separation of genistein from other soybean isoflavone aglycone (SIA) homologues. The present work provided a novel method for separating genistein from its structurally similar homologues by ionic liquid (IL)-based liquid-liquid extraction using hydrophobic IL-water or hydrophilic IL/water-ethyl acetate biphasic systems. Factors that influence the distribution equilibrium of SIAs, including the structure and concentration of IL, pH value of the aqueous phase, and temperature, were investigated. Adequate distribution coefficients and selectivities over 7.0 were achieved with hydrophilic IL/water-ethyl acetate biphasic system. Through a laboratory-scale simulation of fractional extraction process containing four extraction stages and four scrubbing stages, genistein was separated from the SIA homologues with a purity of 95.3% and a recovery >90%.

The potential reuse of soybean husk as feedstock of Eudrilus eugeniae in vermicomposting

BACKGROUND

Soybean (Glycine max L.) is one the most commonly consumed legumes worldwide, with 200 million metric tons produced per year. However, the inedible soy husk would usually be removed during the process and the continuous generation of soybean husk may represent a major disposal problem for soybean processing industries. Thus, the main aim of the present study was to investigate the possibility to convert soybean husk (S) amended with market-rejected papaya (P) into vermicompost using Eudrilus eugeniae.

RESULTS

Soybean husk was mixed with market-rejected papaya in different ratios to produce five different treatments (1P:1S, 2P:1S, 1P:2S, S only and P only) for laboratory screening of solid wastes. Generally, the application of E. eugeniae permitted a significant increase in Ca (42.3-91.6%), K (93.8-235%), Mg (25.4-84.6%) and P (37.1-129%) but a decrease in the C:N ratio (21.4-52.8%) after 9 weeks of vermicomposting. Among all the treatments investigated, soybean husk which was mixed with an equal amount of market-rejected papaya (1P:1S) showed superior quality vermicompost. Waste mixtures also encouraged the growth of E. eugeniae except the treatments with soybean husk alone as well as soybean husk which was mixed with market-rejected papaya in 1P:2S ratio.

CONCLUSION

Vermicomposting could be used as an efficient technology to convert soybean husk into nutrient-rich organic fertiliser if it was mixed with market-rejected papaya in appropriate ratio.