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SOLID‐STATE BIOCONVERSION OF PHENOLIC ANTIOXIDANTS FROM DEFATTED SOYBEAN POWDERS BY RHIZOPUS OLIGOSPORUS: ROLE OF CARBOHYDRATE‐CLEAVING ENZYMES
Author(s) -
McCUE PATRICK,
HORII AKIYO,
SHETTY KALIDAS
Publication year - 2003
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.2003.tb00597.x
Subject(s) - rhizopus oligosporus , bioconversion , chemistry , fermentation , food science , solid state fermentation , enzyme , rhizopus , isoflavones , carbohydrate , antioxidant , biochemistry
ABSTRACT Consumption of soybeans has been linked to a reduction in risk of numerous chronic diseases. The health benefits of soybean consumption have been linked to nutritionally functional phenolic compounds known as isoflavones. As the majority of plant phenolics exist naturally as glucoside‐bound moieties, we investigated the efficacy of increasing phenolic content in defatted soybean powder by fermentation with a glucosidase‐excreting fungus, Rhizopus oligosporus, and further investigated the involvement of carbohydrate‐cleaving enzymes (α‐amylase, α‐/β‐glucosidase) in phenolic antioxidant mobilization. Phenolic content increased 41% in water extracts and 255% in ethanol extracts after 10 days of fermentation, and associated with β‐glucosidase activity. The results suggest that solid‐state fermentation with R. oligosporus is an excellent strategy for increasing phenolic content in defatted soybean powder and that β‐glucosidase is the main carbohydrate‐cleaving enzyme that is required for efficient phenolic mobilization from powdered soybean. The results have potential importance for the commercial development of enzymatic strategies for utilizing the maximal phenolic potential of soybean substrates for use as nutritionally functional food ingredients.