Preparation and characterization of pH-sensitive intelligent packaging films based on cassava starch/polyvinyl alcohol matrices containing Aronia melanocarpa anthocyanins

Intelligent packaging films have sparked interest due to their capacity to indicate food freshness. In this study, a pH-sensitive packaging film was developed using the cast film process, with cassava starch and polyvinyl alcohol (PVA) as substrates. Aronia melanocarpa anthocyanins (AMA) were incorporated as visual indicators of pH changes. The study assessed the impact of the cassava starch/PVA ratio and AMA content on the films' physical, structural, and pH-sensitive properties. It evaluated their potential for monitoring milk freshness. The results revealed that films with a starch/PVA ratio 3/7 achieved optimal tensile strength (TS) and elongation at break (EAB). The incorporation of AMA into the films enhanced their UV barrier properties. Notably, the compatibility between starch and PVA was improved when the film contained 1 g (g) of AMA per hectogram (hg) of the total mass of starch and PVA. Specifically, the enhanced compatibility was evident through differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) analysis. Furthermore, the films demonstrated notable color changes within a pH range of 2–11, indicating their potential for monitoring milk freshness. These findings suggested that the films containing AMA hold great promise for applications in intelligent packaging within the food industry.