Abstract: This study investigated the regulatory mechanisms of a composite film loaded with epigallocatechin gallate (EGCG) and thyme essential oil (TEO) on the cuticular wax and storage quality of post-harvest blueberries, providing theoretical and practical support for the optimization of blueberry post-harvest preservation technology. The results indicated that the composite film effectively slowed the decline in the total wax content of blueberry peels, while maintaining the proportion of key functional components in the cuticular wax, retaining its microstructural integrity, and significantly inhibiting the downregulation of wax-related genes in the VcKCS family. Regarding fruit quality, on the 6th day of storage, the composite film treatment effectively delayed the decline in blueberry firmness and inhibited the increase in rot incidence and mass loss, thereby helping maintain blueberry fruit quality. Furthermore, a decrease in the total wax content of blueberry peels during storage resulted in a decline in their L* value, and the treatment effectively mitigated this color deterioration. Further correlation analysis revealed that the total wax content of blueberry peels was significantly positively correlated with fruit firmness, L* value, and mass loss rate, and was significantly negatively correlated with rot incidence. This indicates that the stability of cuticle wax was key to maintaining fruit quality during storage. In summary, the composite film indirectly mitigates the decline in the total wax content and structural deterioration by delaying overall fruit senescence and regulates the expression of related genes to enhance the fruit’s barrier function, thereby delaying quality deterioration. This finding provides a reliable technical reference for the postharvest preservation of blueberries.

Key words: thyme essential oil; epigallocatechin gallate; blueberry; wax; storage quality