Preparation and characterization of nano-SiO2-modified emulsified film and its application for strawberry preservation

To extend the shelf-life of strawberries, this study analyzed the effect of nano-SiO2 on a composite film of gelatin (GE) and Camellia oil (CO). The emulsified film properties of GE and CO containing various nano-SiO2 mass fractions were investigated. Results demonstrated that 5% nano-SiO2 increased compatibility with GE and CO, produced a smooth and structurally dense film, and enhanced thermal stability and mechanical properties. Moreover, 5% nano-SiO2 improved barrier properties. The water vapor permeability, oxygen permeability, carbon dioxide permeability, and oil permeability decreased by 72.95%, 17.44%, 17.27%, and 18.68%, respectively, compared with those in the GE emulsified film. Strawberries sealed with an emulsified film containing 5% nano-SiO2 showed the maximum suppression in weight loss rate and lipid oxidation of strawberries, and the highest maintenance in respiration intensity, peroxidase, and catalase activities. The above results revealed that nano-SiO2 enhances the functionality of emulsified films, and composite films are potential packaging materials for extending the shelf life of strawberries.