Effect of the non-covalent complex of anthocyanins and whey protein on fish oil emulsions: Evaluation of stability, antioxidant properties, and bioaccessibility

The nutritional efficacy of fish oil is significantly limited by its high susceptibility to oxidative degradation and low bioavailability. In this study, a non-covalent complex composed of anthocyanins (ANC) and whey protein (WP), was rationally designed and utilized to develop a fish oil emulsion system aimed at enhancing oxidative stability and bioaccessibility. The fluorescence spectroscopy (INF), Fourier transform infrared spectroscopy (FTIR) and Far UV circular dichroism (CD) demonstrated specific molecular interactions were generated between ANC and WP. Upon emulsification, the WP-ANC complex at 0.4 wt% acted as an effective emulsifier, yielding emulsions with reduced droplet size and enhanced antioxidative stability. Comparative analysis revealed that WP-ANC stabilized emulsions exhibited superior inhibition of lipid oxidation compared to those stabilized solely by WP, thereby significantly enhancing the stability of fish oil. Under simulated in vitro gastrointestinal digestion, the emulsion formulated with 0.4 % ANC and WP promoted lipid droplet breakdown, suppressed oxidative degradation during digestion, decreased the release rate of free fatty acids, and consequently enhanced the bioavailability of fish oil.