Milling of wheat bran: Influence on digestibility, hydrolysis and nutritional properties of bran protein during in vitro digestion

Wheat bran is a source of high-quality protein with low cost, but the accessibility of bran protein is notably limited by cell wall matrix. This study investigated the effect of milling on the distribution and profile of wheat bran protein, and explored its digestibility, hydrolysis and functional activity during in vitro digestion. It showed that superfine milling effectively released bran protein by disrupting aleurone cells and further improved its solubility and extractability. Superfine wheat bran (19 μm) had higher protein digestibility (53.1 %) and hydrolysis degree (12.7 %) compared to coarse wheat bran (84–1110 μm). Moreover, intestinal digestion promoted the release of free amino acid, mainly arginine (16.4 %), tyrosine (12.8 %) and phenylalanine (9.5 %). Superfine bran protein hydrolysate exhibited the highest antioxidant activity and starch-digestive enzyme inhibitory activity that could facilitate the application of bran as a multifunctional nutrient.