Effect of fermentation with Monascus pilosus on the antioxidant activities and phenolic acid contents of adzuki bean (Vigna angularis)

Abstract

Objective: To enhance physiological activities of adzuki bean (Vigna angularis) via fermentation with Monascus pilosus (M. pilosus). Methods: The adzuki bean fermentation conditions with M. pilosus were optimized, and the effect of Monascus-fermentation on the antioxidant capacity and phenolic acid contents of adzuki bean was investigated. Results: Optimal fermentation conditions were determined by the production of monacolin K. The highest monacolin K production was observed in 5% inoculum sized on day 15 in fermentation. Free and bound phenolic acids were isolated from native and fermented adzuki bean. A 1.9-fold decrease was observed in bound p-coumaric acid content, whereas the contents of bound ferulic and sinapic acids were increased by 28- and 1.7-fold, respectively. However, the contents of free phenolic acids such as p-coumaric, ferulic, and sinapic acids were increased by 2.6-, 5.2-, and 7.2-fold, respectively. The fermentation of adzuki bean by M. pilosus enhanced the activities of DPPH ● radical scavenging, ferrous ion-chelating, nitric oxide scavenging, and ferric antioxidant reducing activities 2.2-, 1.7-, 1.2-, and 1.8-fold, respectively. Conclusions: Results from our study suggest that the contents of p-coumaric, ferulic, and sinapic acids in adzuki bean were highly increased by fermentation with M. pilosus, resulting in enhanced various antioxidant activities. journal homepage: www.jclmm.com