Effect of different zein/tea polyphenol/apple pectin coating on nutritional, physicochemical properties of fresh walnut kernel preservation

In this study, zein/apple pectin/tea polyphenol layer-by-layer assembled cling film prepared by solution casting was characterized, and the preservation effect of composite coatings, double, triple, and quadruple multilayer layer-by-layer assembly coatings on fresh walnut kernels at 4 degrees C was evaluated. As the number of assembly layers increased, the water vapor barrier increased, and the lower the film's UV transmittance. The assembled film's antioxidant and antibacterial activities were significantly higher than composite film. The moisture, color, and texture of the fresh walnut kernels treated with the assembled coatings were less different from 0 d fresh walnut kernels after 40 d of storage at 4 degrees C. The acid value, peroxide value, and total number of bacterial colonies of the fresh walnut kernels with 4-layer assembled coatings were significantly lower than those of the composite coatings. Overall, zein/apple pectin/tea polyphenol layer-by-layer assembled coating is an effective way to the fresh walnut kernel preservation.