Corn starch/polyvinyl alcohol based films incorporated with curcumin-loaded Pickering emulsion for application in intelligent packaging

The intelligent pH indicator films were prepared by incorporating curcumin-loaded Pickering emulsion with corn starch (CS) and polyvinyl alcohol (PVA) matrix. The mechanical properties, barrier properties and functional characteristics of the films were studied and the films were applied to monitor fish freshness. Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM) showed that Pickering emulsion can form hydrogen bonds with CS and PVA. The antioxidant activity of the films was detected, which showed that Pickering emulsion could reduce the decomposition of curcumin during the process of preparation and storage. Bactericidal tests showed that the films can inhibit the growth of S. aureus, B. subtilis, and E. coli, and the effect of the films on Gram-positive (G(+)) bacteria is stronger than Gram-negative (G(-)) bacteria. Application of the films presented here is supported by an activation test of Pangasius bocouti. With time changed, the color of films changed from yellow to red, and the color change of films prepared with curcumin-loaded Pickering emulsion was more evident than the films prepared with curcumin solution. Therefore, the films prepared with curcuminloaded Pickering emulsion had better performance and can be used to indicate the quality of food.