Effects of Pine Needle Essential Oil Combined with Chitosan Shellac on Physical and Antibacterial Properties of Emulsions for Egg Preservation

In this study, the structural changes of chitosan- (C) shellac (S) bio-based emulsions induced by the incorporation of pine needle essential oil (PNEO) were investigated, in addition to, the effect of enhancements in physical, functional, and antibacterial properties of coatings on egg preservation. The ability of emulsion-based coatings to combine the structural strength of the hydrophilic phase with the hydrophobicity of the lipid was interpreted. Rheological analysis indicated that an appropriate amount of PNEO endowed the coating-forming emulsions (CFE) with proper viscosity and gel properties. The C-S-PNEO3 combined with 0.6 g PNEO had the optimal application and storage stability reflected by the lowest particle size and potential. SEM observed a flatter surface morphology of the coatings with the addition of 0.4 and 0.6 g PNEO, while XRD and FTIR also revealed that PNEO improved the biocompatibility by reducing the crystallinity of the coating, while hydrogen bonds were formed between chitosan, shellac. Furthermore, the physical properties of the coating, such as water vapor permeability (WVP), gas permeability, light transmittance, and color parameters were affected by the PNEO. The results showed that the uniform texture, excellent water vapor, oxygen, ultraviolet (UV) barrier performance, and bacteriostatic effect of the C-S-PNEO3 coating contributed to egg packaging. Highlights PNEO incorporation affected the properties of emulsions as well as the properties of coatings. Coating-forming emulsions have good structural properties and storage stability. C-S-PNEO3 was endowed with strong barrier properties and antibacterial activity for eggs preservation. PNEO had good biocompatibility with C and S determined by XRD. Prepared bio-based emulsion coatings were an emerging egg packaging material.