Starch/polyvinyl alcohol based smart packaging reinforced with recycled pitaya peel-derived anthocyanins for dual-function pork freshness monitoring and shelf-life extension

In this work, pH-sensitive smart packaging films were designed using starch-polyvinyl alcohol (PVA) as the matrix, incorporating anthocyanin and ε-polylysine hydrochloride (ε-PL) to achieve both freshness monitoring and preservation functionalities. All film formulations were prepared in triplicate, and subsequent characterizations of morphological structure, physicochemical properties, and functional bioactivities were conducted on three parallel samples per formulation. Modified films significantly (P < 0.05) enhanced performance relative to starch-PVA films, with hydrogen bonding interactions from anthocyanins and ε-PL boosting antioxidant and antimicrobial performance, along with improving tensile strength and barrier properties, and best performance was exhibited when anthocyanin-to-ε-PL ratio was at 1:2. For pork preservation tests, fresh pork samples were packaged with optimized films, with three independent packaging trials conducted. Prepared films prolonged pork shelf-life for at least two days by significantly (P < 0.05) delayed alterations in total viable counts (reduced by 0.93 and 0.40 Log CFU/g at 37 °C and 4 °C), pH values (reduced by 0.40), color of surface (L* and a* increased by 2.23 and 1.70, b* decreased by 2.29), thiobarbituric acid reactive substances (0.32 mg/kg), total volatile basic nitrogen (3.58 mg/100 g), texture profiles (hardness and springiness reduced by 96.95 N and 1.23 mm, gumminess increased by 50.4 N), weightlessness rate (reduced by 1.40 %), and cook loss of pork (reduced by 2.08 %). Films were effective in monitoring pork deterioration through observable chromatic changes from pink to yellow. The results demonstrate the potential of developed films as dual-functional smart packaging systems for simultaneous meat freshness monitoring and shelf-life extension.