Oscillating-plate ultrasonication of wheat gluten-water-extractable arabinoxylan composites: Structural reorganization and in vitro digestibility

Abstract This study investigated the effects of oscillating-plate ultrasonication on wheat gluten composites containing water-extractable arabinoxylan (WEAX) recovered from wheat gluten processing wastewater. Composites were treated at 40 kHz and a nominal power of 600 W for 0–40 s and characterized by textural, rheological, microscopic, spectroscopic, and in vitro gastrointestinal digestion analyses. WEAX incorporation altered gluten network organization and secondary-structure distribution, reducing hardness by 15.05% and gastric apparent digestibility by 34.31%, while increasing springiness by 14.67%. Ultrasonication induced duration-dependent structural changes, with hardness reaching its highest numerical value of 197.77 ± 18.08 g at 20 s. Changes in disulfide content were accompanied by redistribution of hydrophobic, hydrogen-bonding, and ionic interaction-related fractions. WEAX redistribution and gluten conformational rearrangement may have contributed to these responses. Ultrasonication partly alleviated the WEAX-associated reduction in gastric apparent digestibility, which reached 32.48 ± 0.60% at 30 s but remained below that of gluten without WEAX. Intestinal apparent digestibility showed a numerical decrease followed by recovery with longer treatment. The different treatment durations yielding the highest numerical hardness and gastric apparent digestibility indicate distinct responses of texture and digestive behavior. These findings provide a basis for selecting ultrasonication conditions according to the desired properties of WEAX–gluten composites and for further evaluation of wastewater-recovered WEAX as a cereal protein modifier.