1-1-diphenyl-2-picrylhydrazyl and daidzin

A plastic composite support (PCS) bioreactor was implemented to evaluate the effects on isoflavone deglycosylation in black soymilk fermented by Rhizopus oligosporus NTU 5.. Evaluation for the optimal PCS for mycelia immobilisation was conducted, which led to the significant results that the most mycelium weight (0.237 g per PCS, P < 0.05) is held by an S-type PCS; therefore, it was selected for black soymilk fermentation. It was found that the PCS fermentation system without pH control exhibits better efficiency of isoflavone bioconversion (daidzin to daidzein, and genistin to genistein) than the one with pH control at pH 6.5. As for the long-run fermentation, those without pH control indeed accelerate the isoflavone bioconversion by continuously releasing β-glucosidase into soymilk. Deglycosylation can be completed in 8 to 24 h and sustained for at least 34 days as 26 batches. The non-pH-control fermentation system also exhibits the highest total phenolic content (ranged from 0.147 to 0.340 mg GAE mL(-1) sample) when compared to the pH-controlled and suspended ones. Meanwhile, the black soymilk from the 22nd batch with 8 h fermentation demonstrated the highest DPPH radical scavenging effect (54.7%).. A repeated-batch PCS fermentation system was established to accelerate the deglycosylation rate of isoflavone in black soymilk. © 2015 Society of Chemical Industry.

Topics: Antioxidants; beta-Glucosidase; Biphenyl Compounds; Fermentation; Food Handling; Genistein; Glycosides; Humans; Hydrogen-Ion Concentration; Isoflavones; Picrates; Rhizopus; Soy Milk

The present study describes the biotransformation of a commercially available crude extract of soy isoflavones, which contained significant amounts of the soy isoflavone glycosides daidzin and genistin, by recombinant

Topics: Antioxidants; Bacillus megaterium; Biotransformation; Biphenyl Compounds; Escherichia coli; Glycine max; Glycosides; Isoflavones; Monophenol Monooxygenase; Picrates

This study examined the macronutrients, phytochemicals, and antioxidant activities of yellow soybean sprout (YSS) and green soybean sprout (GSS) with different germination days. YSS and GSS were obtained by sprouting soybean in darkness or with light exposure at 21 °C. Lipid, protein, carbohydrate, and ash contents were analyzed before and after soybean germination. Phytochemicals (total phenolic compounds, saponin, and isoflavone) were also determined. DPPH, ferric reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC) were determined to examine the antioxidant activities of soybean sprout. Results showed YSS had a higher yield than GSS. Based on dry mass composition, 7-d germination of GSS decreased 14% protein, 37% lipid, 22% carbohydrate, and 16% ash, whereas 7-d germination of YSS decreased 6% protein and 47% lipid. Carbohydrate did not change and ash significantly increased for the 7-d germinated YSS. Lipid was greatly metabolized in germination, which explained why the protein relative percentage in dried soybean sprout was higher than that in the corresponding soybean. Total phenolic compounds and saponin (mg/g soybean sprout, dry basis) had the same accumulation trend in soybean sprout with the increases in germination days. Aglycone isoflavones (genistein, glycitein, and daidzein) and daidzin showed an increased trend, whereas malonylgenistin and malonylglycitin showed a decreased trend with germination days for both GSS and YSS. The change in other isoflavones did not show definite trends. GSS had 20% more antioxidant activities than YSS (7-d germinated soybean sprout). The increases in ORAC antioxidant activity suggest eating GSS may be more beneficial than GSS for promoting human health.

Topics: Antioxidants; Biphenyl Compounds; Carbohydrates; Color; Germination; Glucosides; Glycine max; Isoflavones; Light; Lipids; Phenol; Phenols; Phytochemicals; Picrates; Proteins; Saponins