High hydrostatic pressure treatment combined with enzymes increases the extractability and bioactivity of fermented rice bran

Changes in extractability and bioactivity of fermented rice bran (FRB) were investigated using high hydrostatic pressure (HHP) treatment alone (HFRB) and in combination with complex enzymes (CHFRB). The CHFRB treatment resulted in increased contents of total sugars and free amino acids compared to both the HFRB and control groups, which had undergone hot-water extraction. A high performance liquid chromatography analysis showed that CHFRB significantly increased the volume of ferulic acid, although there was no significant difference in total phenolic content among the groups. In bioactivity analyses, the CHFRB extract showed significant increases for inhibiting linoleic acid oxidation and angiotensin-converting enzyme activity compared to those in the other groups. Based on these results, HHP treatment combined with complex enzymes efficiently increased the extractability of ferulic acid and free amino acids, which improved bioactivity. These results provide useful information for using FRB as an ingredient in functional foods and for exploiting HHP treatment combined with specific enzymes to improve the extractability and bioactivity of a raw material. Industrial relevance: This study will give a novel technique for using rice bran, a byproduct of the rice milling process, which contains various bioactive materials since most of them have been discarded uselessly. Our results provide useful information for using rice bran (fermented) as an ingredient source in functional foods and for exploiting HHP treatment combined with specific enzymes to improve the extractability and bioactivity of the raw material.