Effect of Monascus aged vinegar on isoflavone conversion in soy germ by soaking treatment. (1st November 2015)

• Record Type: Journal Article
• Authors: Chen, Ji-Cheng; Wang, Jie; Wang, Zhi-Jiang; Li, Yan-Jie; Pang, Jie; Lin, He-Tong; Yin, Shou-Wei
• Is Part Of: Food chemistry. Volume 186(2015)
• Page Start: 256
• Page End: 264
• Publication Date: 2015-11-01
• Subjects: A-daidzin 6-O-acetyldaidzin -- A-glycitin 6-O-acetylglycitin -- A-genistin 6-O-acetylgenistin -- M-daidzin 6-O-malonyldaidzin -- M-glycitin 6-O-malonylglycitin -- M-genistin 6-O-malonylgenistin -- RP-HPLC reversed-phase high performance liquid chromatography -- TFA trifluoroacetic acid -- p-NPG p-nitrophenyl-β-d-glucopyranoside -- UV ultraviolet -- p-NP para-nitrophenol; Conversion -- Isoflavone -- Soaking -- Soy germ -- Monascus vinegar -- Aglycone; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2015.02.099
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: The interconversion pathway of isoflavone forms was proposed by Monascus aged vinegar soaking. The aglycones in soy germs were increased by 40.76 times via Monascus aged vinegar soaking. Synergistic effects of endogenous β-glucosidase, acid hydrolysis and fermentation were confirmed. Abstract: Soy germ rich in isoflavones has attracted much attention for health-promoting characteristics. An effective approach via Monascus aged vinegar soaking was adopted to enhance the aglycone amount. The profiles and interconversion of soy germ isoflavones via Monascus aged vinegar soaking were investigated, and the distribution in vinegars were also explored. The aglycones were dramatically increased by 40.76 times. Concomitantly, β-glycosides and malonylglycosides were significantly decreased. The proportion of aglycones presented a sharp increase with the endogenous β-glucosidase activity at the initial 4 h incubation. There appeared to be correlations between β-glucosidase activity and the hydrolysis of conjugated isoflavones. The results demonstrated that the reactions of decarboxylation, de-esterification and de-glycosylation were involved in the Monascus aged vinegar soaking, supporting synergistic effects of enzymolysis by endogenous β-glucosidase from soy germ and acid hydrolysis of vinegars. Soaking by vinegar is a promising pathway for preparing aglycone-rich soy germ.