Yogurt fortified with hyaluronic-acid coated liposomal casein peptides: Physicochemical, antioxidant, and sensory properties.

To enhance the antioxidant function of yogurt, hyaluronic acidcoated liposomes encapsulating casein-derived peptides (HA-P-Lip) were added to the yogurt, and the effects on peptide stability during storage, in vitro gastrointestinal release, antioxidant activity, as well as physicochemical and instrumental sensory properties using electronic nose and tongue were evaluated. Six formulations of yogurt were prepared: control yogurt (CY), yogurt with 0.5% casein peptides (Y+P), yogurt with 0.5% Blank-Lip (Y+Blank-Lip), yogurt with 0.5% P-Lip (Y+P-Lip), yogurt with 0.5% Blank-HA-Lip (Y+Blank-HA-Lip), yogurt with 0.5% HA-P-Lip (Y+HA-P-Lip). All samples were stored at 4°C for 21 d. Samples were taken on 0, 7, 14, and 21 d. Compared with the control yogurt (CY), the Y + HA-P-Lip exhibited decreased pH, significantly improved water-holding capacity and reduced syneresis, increased the hardness, consistency and viscosity, and improved the microstructure, making it denser and more uniform. Importantly, addition of casein peptides improved the antioxidant activity of yogurt, and HA-P-Lip effectively maintained the antioxidant activity of yogurt, which was significantly better than a group of free casein peptides added. The Y + HA-P-Lip showed better sustained peptides release in vitro gastrointestinal digestion. The analysis of electronic nose and electronic tongue indicated that the Y + HA-P-Lip showed higher response value in the volatility of alkanes, and was superior to the CY in umami and richness. HA-P-Lip demonstrated superior antioxidant activity retention and sustained peptide release during in vitro digestion without negative effects on yogurt quality. This study will provide new strategies for the application of peptide active ingredients in functional foods.