Development of Anthocyanin‐Containing PVA/Purple Sweet Potato Films as pH‐Sensitive Indicators for Pork Freshness Monitoring

ABSTRACT

Purple sweet potato is rich in acylated anthocyanins that exhibit pH‐dependent color changes, making it a promising natural indicator for smart packaging. In this study, purple sweet potato powders were prepared by steaming and freeze‐drying, which retained the anthocyanin, phenolic, and antioxidant contents. Purple sweet potato was combined with PVA at a ratio of 75% to create a film capable of changing color due to the properties of anthocyanins. The physicochemical properties of the film included a thickness of 210 um, moisture 3.53%, solubility of 50.99%, swelling of 237.53%, water permeability of 9.77 g/s.cm, TPC of 10.94 mg/g, TFC of 4.78 mg/g, and TAC of 3 mg/g. When applied to the pork sample, the polyvinyl alcohol/purple sweet potato film at 75% signaled a color change from pink to blue, indicating increased mold bacteria and yeast concentrations. These findings highlight the feasibility of polyvinyl alcohol/purple sweet potato films as biodegradable, pH‐responsive smart packaging materials for monitoring meat quality.