Wheat bran arabinoxylan alleviates freezing-induced starch damage: multiscale structure, pasting properties, and digestibility

This study investigated the protective mechanism of wheat bran arabinoxylan (WBAX) on frozen starch by examining the effects of WBAX molecular weights and addition levels on multiscale structure, pasting properties, and in vitro digestibility of frozen starch. The results of granular morphology analysis showed that WBAX effectively maintained granule surface integrity and inhibited granule agglomeration. Multiscale ordered structural analysis confirmed that WBAX affected the short-range ordered structure, nanoscale lamellar structure, and long-range ordered structure of frozen starch. Specifically, WBAX induced the following changes in frozen starch: relative crystallinity decreased from 22.64% to a minimum of 15.15%; dBragg decreased from 12.57 nm to a minimum of 12.16 nm; and the 1047 cm -1 /1022 cm -1 ratio decreased from 0.91 to a minimum of 0.86. These structural changes influenced the properties of frozen starch. WBAX improved the pasting properties by promoting the hydration and gelatinization of frozen starch, enhancing thermal and shear stability, and inhibiting short-term retrogradation. Furthermore, WBAX modulated the digestibility of frozen starch by maintaining granule integrity, hindering enzyme-substrate contact, and increasing system viscosity, thereby facilitating the conversion of rapidly digestible starch, slowly digestible starch, and resistant starch. Overall, this study elucidates the protective mechanisms of WBAX on frozen starch from the perspective of “multiscale structure-pasting properties-digestibility”, providing a theoretical basis for the precise development of WBAX-based frozen products.