Functionalized polyvinyl alcohol/gelatin films based on loaded curcumin oil-in-water emulsions for meat freshness monitoring

Responding to growing food spoilage concerns, especially in meat, this study develops an intelligent film with integrated antibacterial and spoilage-indicating functions. Fat-soluble curcumin (Cur) was dissolved in perillaldehyde (PAE) to enhance antibacterial activity and provide sensing capability. A Pickering emulsion (ZS-PAEC), stabilized by binary nanoparticles (ZS) via ultrasonic emulsification, greatly improved Cur's photostability: unencapsulated curcumin degraded rapidly within 2 h with a retention rate of only 0.065 %. In contrast, encapsulated curcumin had a high retention rate of 59.17 % and 4 % after 2 h and 12 h, respectively. The emulsion was blended with polyvinyl alcohol-gelatin (PG) and cast into PGZPC films, which showed enhanced water resistance, mechanical strength, pH/ammonia sensitivity for monitoring pork freshness and antioxidant efficacy of up to 53.48 %. The film maintained high responsiveness over 10 reuse cycles, demonstrating a viable strategy for smart biodegradable meat packaging. • Curcumin and perilla aldehyde were added to the ZS-stabilized Pickering emulsion. • Application of curcumin pH sensitivity in smart food packaging film. • PGZPC composite film has excellent ammonia sensitivity and recyclability. • PGZPC film has a significant effect on indicating meat freshness.