To comprehensively explore the fresh-keeping mechanism of citral nanoemulsion/chitosan composite coating on citrus fruits, the study first characterized the effect of citral nanoemulsion additions (10%, 20%, and 30%, mass ratio) on the tensile properties and permeation properties of the chitosan films, as well as the effect on the wetting properties of the coating solution on the fruit peel. And then the effect of composite coating on the storage quality of tangerine fruit was measured. Results showed that the citral nanoemulsion enhanced the plasticity of the chitosan film and improved the water vapor and oxygen transmission coefficient of the film. The contact angle of the coating solution on the fruit peel decreased by adding 10% nanoemulsion from 80.49° to 66.2°, and the spreading coefficient increased from -53.48 mN/m to -23.02 mN/m, which improved the wettability of the coating solution to the fruit peel and increased the interfacial interaction between them. When the citral nanoemulsion/chitosan composite coating was used for the preservation of tangerine, it inhibited the fruit rotting, reduced its respiration intensity, and maintained a relatively stable nutrient content. Among them, the coating with a nanoemulsion content of 20% had the best inhibitory effect on fruit rotting with a rotting rate as low as 16.67% after 19 days of storage, while the rotting rate of the control group exceeded 30%. Therefore, the addition of citral nanoemulsion can not only improve the spreading performance of the coating film on the fruit peel to improve the structure of the coating film but also reduce the infection of microorganisms on the fruit through the release of citral, thereby significantly improving the storage quality of the fruit and showing good application potential in postharvest preservation of fruits.
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