Preparation of antifogging and enhanced antimicrobial biopolymer coating and its applications in lettuce preservation

This study focused on the development of a new biopolymer coating with antifogging and antimicrobial properties. The dual functional coatings, which consisted of multiple layers of chitosan (CS) and alginate dialdehyde (ADA), were prepared by layer-by-layer assembly driven by Schiff base, hydrogen bonding, and electrostatic interactions. Fourier transform-infrared spectroscopy indicated the formation of a Schiff base between CS and ADA. The six-layer coating had high transparency, optimum hydrophilicity and antifogging property as characterized by spectroscopy, water contact angle analysis and antifogging testing. The antibacterial activity of the six-layer coating was better than that of CS alone. Furthermore, the six-layer coating reduced decay of fresh-cut lettuce during storage. The results from this study suggest that coatings consisting of CS and ADA can prevent fogging, inhibit microbial growth, and maintain the quality of fresh produce throughout storage.