pH-Sensitive Cassava StarchOnion Peel Powder Films as Colorimetric Indicators for Minced Beef Freshness Monitoring

pH-sensitive intelligent films offer a novel strategy for real-time monitoring of food fresh- ness via visible color changes. This study valorizes onion peel powder (OPP), a polyphenol- rich agro-industrial by-product, by incorporating it into cassava starch-based films at three concentrations (1O, 2O, 3O). Increasing OPP content led to significantly higher total phenolic and flavonoid levels, enhancing the films’ antioxidant properties (p < 0.0001). While the films exhibited selective...