Collagen peptides increase curcumin bioaccessibility in milk protein-stabilized emulsions by increasing mixed micelle solubilization capacity.

Collagen peptides (CPTs) are common ingredients in protein-rich functional beverages. However, the impact of CPTs on the digestion behavior of nutraceutical-fortified functional beverages remains poorly understood. We therefore investigated the effects of CPT on the structural, physicochemical, and digestion properties of curcumin-loaded milk protein concentrate (MPC)-stabilized emulsions. CPT addition had little impact on the physicochemical stability or encapsulation efficiency (>95 %) of MPC emulsions. In vitro digestion experiments showed that CPT addition increased curcumin bioaccessibility (1.14- to 1.35-fold), but slightly decreased lipid hydrolysis of MPC-emulsions. Microstructural analysis of the digesta indicated that the presence of CPT induced the formation of hollow vesicle structures in the small intestinal phase. The presence of CPT in the soluble fraction of the digesta increased the solubilization of oleic acid in a dose-dependent manner. The results suggest that CPT enhance the bioaccessibility of curcumin in fortified beverages, thereby enhancing the nutritional profile of these products.