Design and characterization of bio-amine responsive films enriched with colored potato (Black King Kong) anthocyanin for visual detecting pork freshness in cold storage

Intelligent films serving as a response to a particular stimulus (e.g., biogenic amines) endow great potential to monitor the meat freshness. The aim of this study was to develop intelligent films with excellent antioxidant properties based on starch/glycerol/gelatin and colored potato (Black King Kong) anthocyanins (CPA) to monitor pork freshness in cold storage (4 °C). The CPA component was first detected by ultra-high liquid chromatography-mass spectrometry. The physicochemical and antioxidant properties as well as the pH-sensitivity of films were investigated. Two stable components (peonidin chloride (51.7%) and malvidin 3-O-glucoside chloride (18.0%)) were detected in extracted CPA. With CPA incorporated, an evident decrease in water vapor permeability and light transmittance, but a highly increase in elongation at break and scavenging ability for DPPH+ (60.87%) and ABTS+ (53.38%). The films showed color change lower than 2.5 under 4 °C and existed great NH3 sensing ability. The pork freshness application test proved CPA film existed obvious color changes with the inner increased TVBN contents. Furthermore, the polynomial model proved that the color parameter (b, yellowness) fit well with the TVBN (R = 0.94), which was critical to predicate pork freshness. Therefore, the intelligent films can be expected as intelligent packaging for detection pork freshness in cold storage to ensure their safe consumption.