Chitosan coating formulated with citric acid and pomelo extract retards pericarp browning and fungal decay to extend shelf life of cold-stored lychee

Lychee (Litchi chinensis Sonn.) is a subtropical fruit of high market value. It is characterized by bright red pericarp and strong exotic aroma and taste. However, harvested lychee fruits have only a few days of shelf life due to rapid pericarp browning and fruit rot. While edible coatings have been employed to improve storability of lychee, whether essential oil further enhances the function of coatings is less understood. Here, we investigated the effect of 1% and 2% pomelo extract (PE) applied in combination with 0.5% and 1% chitosan-citric acid coating on cold-stored lychee. Application of 1% chitosan plus 2% PE coating significantly reduced browning, weight loss, and disease severity by 16.5%, 28.0%, and 65.7%, respectively as compared to the control fruits after storage at 5 °C for 14 d followed by 20 °C for 3 d The treatment extended fruit shelf life by at least 2 d, in which 73.3% of the fruits retained marketability and exhibited superior sensory quality. In conclusion, we developed an efficient coating formula that used PE as a sustainable fungicide to inhibit fungal decay and improve storability of perishable fruit.