Contrasting structural evolution of starch and protein in aged wheat is associated with interfacial disintegration:...

Wheat aging alters starch-protein organization within the endosperm, but its consequences for nutrient digestion and animal performance remain unexplored. This study showed that starch disordering and protein oxidative cross-linking (disulfide bonds: 5.47 μmol/g) were associated with deterioration of the starch-protein interface. Quantitative confocal microscopy supported this interpretation, showing a 28.8% reduction in spatial colocalization. This deterioration was accompanied by altered digestive kinetics, characterized by an 11.35% increase in starch digestibility and a 51.17% decrease in protein digestibility (P < 0.05). In vivo broiler trials supported the physiological relevance of these alterations, as aged-wheat diets were associated with a 28.9% reduction in 42-day body weight. Gluten-hydration-based equations were developed to track nutrient evolution, and predictive models using physicochemical traits were established to assess digestibility (R² ≥ 0.81) and broiler metabolic performance (R² ≥ 0.91). These findings provide mechanistic insights and a preliminary framework for targeted utilization of aged wheat.