05) up to 120 h, which still failed to exceed the content of unfermented rice bran (RB). Ryan et al. (2011) also noted a reduced p-coumaric acid content after fermenting rice bran with S. boulardii. Chlorogenic and p-hidroxybenzoic acids and vanillin showed an increase in their content throughout

the fermentation. Protocatechuic acid did not show any significant increase (p < 0.05) after 24 h, whereas gallic and caffeic increased until 72 h, and syringic and ferulic acids increased their content until up to 120 h of fermentation. Gallic and ferulic acid contents displayed the most substantial content increases during fermentation, of about 60 and 20 times, respectively, compared to their contents in unfermented rice bran. The changes produced by fermentation on the profile of phenolic acids depend on the Tenofovir research buy type ABT-888 chemical structure of substrate, the fungus used and the conditions of fermentation ( Martins et al., 2011 and Schmidt and Furlong, 2012). Agro-industrial residues of vegetables and cereals such as bran, bagasse, straw, corn cob, among others are lignocellulosic materials mainly composed by cellulose, hemicellulose and lignin. The lignin fraction of these materials contains numerous phenolic compounds, mainly acids such as ferulic, coumaric, syringic and hydroxybenzoic, which can also be recovered by SSF. Since fungi

grow on these residues, they use the polysaccharides Glutathione peroxidase after lignin degradation in order to grow and reproduce (Martins et al., 2011 and Sánchez, 2009). Ferulic acid was the phenolic compound that stood out during the fermentation process, with over 700 mg/g produced (Table 1). The release of ferulic acid from agricultural byproducts by enzymatic methods has been increasingly researched, with most studies using yeast as an enzyme source (Martins et al., 2011). Ferulic acid has commercial potential, and may be applied as a natural precursor of vanillin, natural antioxidant, preservative agent in food products, anti-inflammatory agent and

photo-shield (Yang, Yue, Cao, Zhang, & Wang, 2009). Vanillin is one of the most commonly used flavouring agents in food products, fragrances, beverages and pharmaceuticals, and has recently been indicated in the bioconversion of ferulic acid in order to decrease vanillin production costs (Zheng et al., 2007). Our results suggest that the use of the R. oryzae fungus in rice bran could produce the enzymes capable of releasing ferulic acid residues and agro-industrial byproducts. The antioxidant activity of the phenolic compounds was evaluated by inhibiting free radical DPPH, expressed in terms of the ability to reduce/sequester the free radical. Compared to others, this is a widely used method to evaluate the antioxidant capacity in a short time interval (Rufino et al., 2009 and Sánchez-Moreno et al., 1998).