蓝莓花青素-大豆分离蛋白指示膜对三文鱼新鲜度的可视化监测OA

To address the lack of visual freshness monitoring methods for cold-water fish during storage and transportation,a blueberry anthocyanin-soy protein isolate(SPI)pH-responsive indicator film was developed.Using SPI as the film-forming matrix,blueberry anthocyanins at mass fractions of 0,2%,4%,6%,8%,and 10%relative to SPI dry mass were incorporated,and the films were prepared by solution casting.The mechanical properties,microstructure,light transmittance,and pH-responsive color difference values of the indicator films were characterized.The color changes and UV-Vis absorption spectra of anthocyanin solutions were analyzed over a pH range of 2-13.The indicator films were attached to the surface of salmon and stored at 35℃for 12 h to monitor changes in fish pH and film color.The results showed that the film with 8%anthocyanin content exhibited the best overall performance,with tensile strength increasing from 17.67 MPa(0%addition)to 23.71 MPa,elongation at break reaching 45.80%,and a smooth surface with a dense cross-sectional structure.In the pH range of 2-13,the anthocyanin solution gradually changed from red to yellowish-brown,with the maximum absorption wavelength red-shifting from 512 nm to 590 nm.The color difference values at all tested pH levels exceeded 5,indicating visually distinguishable color changes.During salmon storage,the indicator film exhibited a color transition pattern of"deep purple-red→purple-red→reddish-brown→dark brown",which corresponded well to the pH evolution of the fish flesh(initially decreasing and then increasing during spoilage).This study provides an intuitive and convenient new approach for quality monitoring of cold-water fish in cold-chain transportation.