EFFECT OF YEAST FERMENTATION CONDITIONS ON POLYPHENOLS ENRICHMENT FROM RICE BRAN

Abstract

Fermented rice bran by microorganisms is capable to enrich polyphenols. The fermented products from rice bran have anti-tumor properties. It can prevent cerebral thrombosis, brain infarrt and pulmonary thromboembolism, as well as increase immunity. The microorganisms for fermentation usually are mold, yeast, lactic acid bacteria. They are safe microorganisms used in traditional fermentation products. Six strains of S. cerevisiae in Culture Collection of Food Industries Research Institute have been selected for rice bran fermentation and all of them are capable of enhancing the polyphenol ennichment in rice bran. In particular, strains CNTP7072 are the best to extract polyphenols (544 mg /l), more than 150 % compared with unfermented rice bran. The CNTP7072 can extract 587 mg/l polyphenols from rice bran medium, more than 163 % compared with unfermented medium at proper fermentation conditions (rate of seed: 6×10⁷ cells/ml, pH 6.5, temperature 30 oC, static culture, fermentation time: 24 hour)