Structural breakdown of cell walls induced by fermentation
may occur, leading to the liberation and/or synthesis of various bioactive compounds (Katina et al., 2007b). For example, in the present study, the existence of q-coumaric acid content in non-fermented and A. oryzae-fermented rice bran extracts as well as caffeic acid in A. oryzae- and R-oryzae-fermented rice bran is suggested to be attributed to the fact that ferulic
acid can be bio-transformed into smaller compounds. During fermentation, enzymes such as amylases, xylanases and proteases derived from both the substrates and fungi contribute
to the modification of substrates’ composition. Zheng and Shetty (2000) supported this suggestion, by stating that an improvement in phenolic acids content usually relates to the
action of fungal enzymes such as b-glucosidase, a-amylase and laccase, along with other enzymes, which play essential roles in the immobilization of bioactive phenolic compounds during solid-state fermentation. On the other hand, Ju et al.