Effect of Pickering emulsion on the physical properties, microstructure and bioactivity of corn starch/cassia gum composite films

Abstract

This study aimed to evaluate the effects of anise essential oil Pickering emulsion (AEO-PE) on the corn starch/cassia gum (CS/CG) composite films in terms of mechanical properties, microstructure and bioactivity, to obtain non-polluting food-active packaging composite films that can replace plastic products. The results of scanning electron microscope (SEM) image results demonstrated that AEO-PE with an oil/water phase ratio of 6:4 (AEO-PE-6:4) was evenly distributed within the matrix of the composite films. The results of thermogravimetric analysis (TGA) demonstrated an improvement in the thermal stability of the composite films. The results of water vapor permeability (WVP) showed a significant improvement in the capacity of the composite film to block water vapor. Further, the DPPH and ABTS radical scavenging rates of the composite films significantly increased after adding of AEO-PE emulsion, and an excellent barrier effect on UV light was observed. These results proved that the composite films had good antioxidant activity. It was also found that the combination of the CS/CG films and AEO-PE-6:4 effectively inhibited the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Overall, the incorporation of AEO-PE-6:4 resulted in enhanced antioxidant, antibacterial, mechanical, and barrier properties of the CS/CG composite films. The application of the CS/CG-PE-0.7% film to A. bisporus effectively retarded browning and spoilage and maintained the texture and color of the A. bisporus. This study might provide a theoretical basis for the incorporation of PE into starch hydrophilic colloidal matrix composite films, facilitating the disposal of plastic waste.