Effect of bovine serum albumin and Copigments on the stability of Haskap berry anthocyanin extracts at neutral pH

Haskap berry anthocyanin extract (HAE), a high-value and high-potential natural pigment, is prone to degradation by external factors such as heat and light. To improve the chemical and color stability of HAE, the binary and ternary composite system of HAE, BSA and copigments was compared for the protection of anthocyanin in the heat and light treatments at neutral pH. Compared to the binary composite system of HAE with BSA and ferulic acid (FA), the select HAE-BSA-FA ternary composite system decreased the total anthocyanin degradation rate (TADR) to 65.26 % and 70.06 % after heat and light treatments, and the color difference value (ΔE) to 43.59 % and 71.64 %, the bioaccessibility index (BAI) at the conclusion of gastric digestion and intestinal digestion increased 17.52 % and 44.57 %, which had a better protective effect on the thermal, light and in vitro digestion stability of HAE. Results of fluorescence spectroscopy, circular binning, FTIR spectroscopy, SDS-PAGE, and particle size analysis indicated that the stability of HAE was promoted by non-covalent binding with BSA and FA, such as hydrogen bonding, electrostatic force. HAE, BSA, and FA are complexed by hydrophobic interactions, and the secondary structure of BSA was changed in the process.