Role of silica (SiO2) nano/micro-particles in the functionality of degradable packaging films/coatings and their application in food preservation

Background: Due to the environmental pollution caused by plastic packaging films and the health concerns caused by micro-plastic migration into food, development of degradable food packaging films (DFPFs) based on biopolymers with enhanced properties and via nano-additives is a popular stream in the food science field. Many studies have shown that DFPFs containing silica (SiO2) are potential alternatives to replace plastic packaging materials. Scope and approach: This work covers the development in DFPFs containing SiO2 in the last decade, focusing on the effects of SiO2 on different DFPFs in terms of light barrier, gas barrier, mechanical, and antimicrobial properties along with water sensitivity. In addition, the effect of SiO2 on the controlled release of other bioactive compounds and the application of DFPFs containing SiO2 for fresh food preservation are summarized. Key findings and conclusions: The addition of SiO2 could improve the performance of DFPFs comprehensively. The effect of SiO2 on the properties of DFPFs is mainly related to the concentration of SiO2, its dispersion state in the films, and the interaction forces between SiO2 and the film matrix. There is a key “optimum” concentration for the incorporation of SiO2. Due to the mesoporous properties of SiO2, it can be loaded with other bioactive for coapplication and enhancing the antioxidant and antimicrobial properties of DFPFs by improving the controlled release of bioactive in them. Importantly, DFPFs/coatings containing SiO2 have shown surprising effects in preserving a variety of fresh foods.