聚乙烯醇-壳聚糖基抑菌指示膜的制备及在冷鲜肉中的应用

基于聚乙烯醇（polyvinyl alcohol，PVA）-壳聚糖（chitosan，CS）为成膜基材，蒙脱土（montmorillonite，MMT）负载茶多酚（tea polyphenols，TP）为抑菌剂，溴甲酚紫（bromocresol purple，BCP）、甲基红（methyl red，MR）及其复配物为指示剂制备多功能食品包装膜。研究BCP、MR及其复配和MMT负载TP对PVA-CS薄膜物理和功能特性的影响，并将其应用于冷鲜肉的保鲜指示。结果表明：各组分之间相容性较好；指示剂的添加增强了共混膜的结晶度，改善了薄膜的物理性能和光学性能；指示膜均能对氨气响应，其中BCP与MR质量比为1.5∶1时最为灵敏。抑菌剂的添加明显提高了薄膜的耐水性、水蒸气阻隔性、抗氧化性以及抑菌性。将抑菌指示膜应用于冷鲜肉的新鲜度监测及保鲜实验，发现BCP与MR质量比1.5∶1薄膜的颜色变化与冷鲜肉新鲜度之间存在明显正相关性，且实验组较空白组货架期延长1～2 d，表明抑菌指示膜能够实时监测冷鲜肉新鲜度并有效延长货架期。

Preparation of Antibacterial Indicator Films Based on Polyvinyl Alcohol and Chitosan and Its Application in Chilled Pork

Multifunctional food packaging films were prepared using polyvinyl alcohol (PVA) and chitosan (CS) as film-forming substrates, montmorillonite (MMT)-supported tea polyphenol (TP) as a bacteriostatic agent, and bromocresol purple (BCP), methyl red (MR) or their combinations as an indicator. The effects of BCP, MR and their combination as well as MMT-supported TP on the physical and functional properties of the films were studied, and they were applied to monitor the freshness of chilled pork. The results showed good compatibility between these components. The addition of the indicator enhanced the crystallinity of the blend film and improved its physical and optical properties. The indicator film could respond to ammonia gas, and the highest sensitivity was obtained with a 1.5:1 (m/m) combination of BCP and MR. The addition of bacteriostatic agent significantly improved the water resistance, water vapor barrier performance, antioxidant performance and bacteriostatic performance of the film. When applying the most sensitive antibacterial indicator film to monitor the freshness of chilled pork, a significantly positive correlation was found between the color changes of the film and the freshness of chilled pork, and compared to the control group, the shelf life of chilled pork in the experimental group was extended by 1 to 2 days, indicating that the antibacterial indicator films can real time monitor the freshness and effectively extend the shelf life of chilled pork.