Active Biological Film Improves the Quality of Mutton During Super-Chilling Storage: Effects on Myofibrillar Protein...

Preventing spoilage in food products, particularly in those highly susceptible to rapid deterioration like mutton, has been a persistent challenge in the food industry. In this study, an Active Biological Film (ABF) was developed using chitosan (CS) and whey protein isolate (WPI), with the addition of 0.01 wt% titanium dioxide (TiO₂) and 0.1 wt% white pepper essential oil (WPEO). This ABF was applied to preserve fresh mutton at super-chilling temperatures of -1.7 ± 0.2 °C. The effects of ABF on myofibrillar protein (MP) oxidation and structural characteristics, as well as on the microbial status, physicochemical properties, and sensory quality of mutton, were systematically evaluated. The results demonstrated that, compared to the control group (CK), ABF treatment significantly enhanced the total sulfhydryl content, protein solubility, and zeta potential of MPs, while reducing carbonyl content, surface hydrophobicity, and particle size. MPs in the ABF group showed a higher α-helix proportion and a lower random coil content, along with a notable increase in intrinsic fluorescence intensity. Scanning electron microscopy (SEM) revealed a denser gel structure. Additionally, ABF effectively inhibited microbial growth in mutton, delayed pH increase, reduced thiobarbituric acid-reactive substances (TBARS) and total volatile basic nitrogen (TVB-N), and improved sensory scores, extending mutton shelf life by over 10 days. Therefore, the ABF effectively inhibited oxidation in MPs, maintained their structural integrity, and preserved mutton quality during super-chilling storage.