This study examined antioxidant and antimicrobial activities of medium oat bran treated with four polysaccharide enzymes viscozyme, cellulase, alpha-amylase, and amyloglucosidase. The effects of these enzymes on the release of phenolic acids were determined using reverse-phase HPLC chromatography. Antioxidant assays showed that enzyme pre-treatments significantly increased the hydroxyl radical (HO. ) scavenging activity of all bran samples (16.6-20.0. μM propyl gallate equivalents (PGE)/g bran) relative to untreated bran (13.3. ±. 1.8. μM PGE/g). The order of activity was cellulase. ≈. viscozyme. >. amyloglucosidase. ≈. alpha-amylase. The DPPH free radical inhibitory activities of brans pre-treated with cellulase and amyloglucosidase, 43.0% and 45.0%, respectively were higher than inhibition by untreated bran 21.7% (P. <. 0.05). In the linoleic acid (LA) autoxidation assay, three of the treated and untreated brans similarly inhibited LA oxidation, while viscozyme pre-treated bran had no activity. HPLC analysis showed an increase in free phenolic acids, and this was more pronounced for ferulic and caffeic acids. In the antimicrobial assay, brans pre-treated with viscozyme and cellulase similarly inhibited the growth of Escherichia coli compared to untreated bran (P. <. 0.05), while viscozyme- and alpha-amylase-treated brans enhanced the growth of Bacillus subtilis, a non-pathogenic bacteria strain that has been used as a pro-biotic.

Additional Metadata
Keywords Antioxidant, B. subtilis, E. coli, Oat bran, Phenolic acid
Persistent URL dx.doi.org/10.1016/j.foodres.2013.03.037
Journal Food Research International
Citation
Alrahmany, R. (Roaaya), Avis, T, & Tsopmo, A. (2013). Treatment of oat bran with carbohydrases increases soluble phenolic acid content and influences antioxidant and antimicrobial activities. Food Research International, 52(2), 568–574. doi:10.1016/j.foodres.2013.03.037