Molecular and functional consequences of drying on edible dock powder: Impacts on wheat protein interactions, steamed bun properties, and simulated digestion enzyme inhibition

Abstract

Edible dock, a protein-rich perennial interspecific hybrid Rumex with hypoglycemic potential, is increasingly used in wheat-based products as dock powder (DP). This study investigated the impact of different drying methods (50 °C/80 °C air-drying, freeze-drying) on DP composition, dough properties, steamed bun quality, and post-digestion bioactivity, aiming to optimize DP drying and application for glycemic control. Freeze-dried DP (DP_FD) best preserved dietary fiber, phenolics, and flavonoids, while 80 °C air-drying (DP₈₀) improved bun textural properties. DP_FD dough exhibited greater stability despite a shorter development time. Sensory evaluation favored 5 % DP₈₀-added bun, though DP generally lowered taste/flavor scores. Microstructure analysis revealed gluten network disruption in DP-added doughs, correlating with uneven air cell distribution in buns. SDS-PAGE indicated that low temperature-drying preserved Rubisco large subunits, whereas 80°C-drying promoted gluten protein cross-linking. In vitro digestion studies showed that both DP and DP-added buns inhibited α-amylase and α-glucosidase. Critically, intestinal digesta from DP_FD-added buns showed enhanced α-glucosidase inhibition, strongly correlated with retained flavonoids. These findings demonstrate that drying methods significantly impact DP's functional properties and its effect on post-digestion glycemic responses in wheat products. This suggests that carefully selected drying methods can optimize DP application to create healthier, functional wheat products with improved glycemic control potential.