Preparation and Characteristics of pH-Responsive Composite Packaging Films Based on Curcumin/Microcrystalline Cellulose/Polyvinyl Alcohol/Gelatin

Abstract

With the continuous improvement of food safety awareness, intelligent packaging, as a technology capable of automatically monitoring, sensing, recording, and tracing various circulation links such as food production, transportation, and storage, has emerged. In this study, gelatin (Gel) and polyvinyl alcohol (PVA) were employed as base materials, microcrystalline cellulose (MCC) as the reinforcing phase, curcumin (Cur) as the indicator reagent, and glycerol and distilled water as plasticizers. The solution casting method was utilized to prepare Cur/MCC/PVA/Gel composite films. The microstructure, mechanical properties, barrier properties, pH response properties, and biodegradation properties of the films were analyzed. During the Cur/MCC/PVA/Gel composite film system, increasing the curcumin content led to a decrease in both moisture content (by 13.60%) and hygroscopicity (by 12.69%), and the barrier properties and mechanical properties increased by 19.65% and 21.16%, respectively. In the beef preservation experiment, with the passage of time, the extent of spoilage and deterioration of the beef increased, and the color of the intelligent pH—responsive composite films gradually changed from yellow to dark brown. The pH—responsive packaging material of Cur/MCC/PVA/Gel provides a theoretical foundation for the research on food freshness indicator films.