Research on antioxidant substance extracted from different wheat bran structure layers

The mixed enzymatic and chemical methods were used to degrade pericarp layer, the intermediate layer and aleurone layer of wheat bran in order to release phenolic acids. The composition and content of the extract phenolic acids were determined by HPLC. Moreover, total phenols and the ability of removing free radicals from the extraction were analyzed. The results showed that:the content of ferulic acid dehydrotrimer and dimer were the highest in pericarp layer, up to 4. 34mg/g. However, the content of ferulic acid in the aleurone layer was the highest in the three layers, up to 5. 90mg/g. After being hydrolyzed by enzymes, the contents of ferulic acid dehydrotrimer and dimer from the pericarp layer, the intermediate layer and aleurone layer took up 71. 0%, 52. 6% and 51. 1% of that in the hydrolysate by sodium hydroxide. While the release content of ferulic acid was 46. 9%, 51. 0% and 56. 3% of that in the extraction of alkaline hydrolysis. Total phenolic content in the hydrolysate and their antioxidant capabilities were related to the release of phenolic acids directly.