关键词: 果胶；碱性木质素；茶多酚；生物活性薄膜；脆肉罗非鱼

Abstract: This study fabricated a composite film (P/PVA/L/TP) loaded with alkaline lignin (AL) and tea polyphenols (TPs) by using pectin (PEC) as a substrate, which was crosslinked with polyvinyl alcohol (PVA). The effects of various components on the physicochemical properties of the film, as well as its effect on the preservation of crispy tilapia, were examined. The results showed that the cross-linking of PEC with PVA strengthened the microstructure of the film, significantly improving its mechanical properties and reducing its water solubility from 100% to 50%. Meanwhile, the film loaded with AL showed significantly enhanced UV shielding property while maintaining good transparency. TPs improved the compatibility of components in the film, reduced the water vapor transmission rate, and increased the scavenging capacities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation to 75.40% and 77.49%, respectively. During the storage of crisp tilapia, the P/PVA/L/TP film effectively delayed pH changes, keeping it below 6.6. The content of total volatile basic nitrogen remained lower than 20 mg/100 g during storage. The thiobarbituric acid reactive substances (TBARS) value was significantly lower than that in the control group. In conclusion, the mechanical properties, water solubility, UV resistance and oxidation resistance of the P/PVA/L/TP film were significantly better than those of single component films. Besides, the composite film showed a significant preservation effect on crispy tilapia, thereby having the potential to be a new alternative to plastic wrap.

Key words: pectin; alkaline lignin; tea polyphenols; bioactive films; crispy tilapia