Co-microbiological regulation of phenolic release through solid-state fermentation of corn kernels (Zea mays L.) to improve their antioxidant activity

In this study, regulation of phenolic release and antioxidant activity in corn kernels by co-microbiological fermentation was investigated. The results revealed fermentation with the microorganisms Monascus anka, Saccharomyces cerevisiae and Bacillus subtilis increased the total phenolic content 18.08-fold when compared to that of unfermented corn kernels. Combined with the improvement of alpha-amylase and total cellulase activity, SEM micrographs of corn kernels suggested that microorganism communities might facilitate enzymatic hydrolysis to destroy the cellular structure, regulating phenolic release during fermentation. The chlorogenic acid, vanillic acid, rutin and ferulic acid contents were highly (r > 0.90, p < 0.05) correlated to DPPH and ABTS(+) radical scavenging abilities and contributed to the antioxidant activity of corn kernels. The observed phenolic release and bioactive enhancement indicated that B. subtilis played a positive regulatory role in phenolic mobilization, whereas S. cerevisiae showed a contrasting role when co-cultured with M. anka. This work provides a potential (co-)fermentation process of corn cereals rich in functional phenolics.