The role of arabinoxylan purified from wheat bran in bread and biscuits: Impacts on digestibility and colonic fermentability in vitro

In this study, arabinoxylan (AX) isolated from wheat bran was used to prepare AX-fortified bread and biscuits, and the effects of the amount and method of AX addition on the nutritional properties of baked products were investigated through simulated digestibility and colonic simulated fermentability analysis in vitro. The purified AX demonstrated a high total sugar content (92.75%), high molecular weight (Mw) (669.8 kDa), low polymer dispersity index (PDI) and low arabinose to xylose (A/X) ratio (1.21). In vitro digestibility test indicated that AX addition could dose-dependently inhibit the starch digestibility in both bread and biscuits. Most importantly, it could also dose-dependently transfer more starch and protein into the colon through the gastrointestinal tract, leading to the changes in total amount and chemical composition of food residues. Results from the in vitro fermentability test showed that alterations in the composition of food residue affected its fermentability: a high relative ratio of carbohydrate to protein could enhance its prebiotic effect. This study provides valuable insights into the role of dietary fibres in baked foods, aiming to achieve precise nutrition for high-fibre food products.