Binary Synergistic Effect of Organic Coating and PA/PE Film in Passive Atmosphere on Preservation and Quality of Fresh Lychee during Cold Storage

Lychee (Lychee chinensis Sonn.), a tropical fruit renowned for its attractive red color, sweet taste, and nutritional benefits, faces significant post-harvest challenges. These include color degradation and dehydration due to oxidative stress, which are accelerated by unfavorable storage conditions. This study investigates the combined effects of an organic olive oil-based coating and polyamide/polyethylene (PA/PE) film in passive atmosphere storage on the preservation of lychee during cold storage. Lychee fruits, harvested at commercial maturity, were divided into two groups: one treated with an organic coating made from a blend of Sicilian olive oils (OC) and the other left untreated as a control (CTR). The treated fruits were stored in PA/PE bags, which regulate the exchange of gases and moisture, at 5±1°C and 90±5% relative humidity. The fruits were analyzed at 0 (as fresh), 3, 6, and 9 days of storage for various physical, chemical, microbiological, nutritional, and sensory characteristics. The results demonstrated that the combination of the organic coating and PA/PE film significantly improved the preservation of lychee quality compared to the untreated control. The organic coating acted as a protective barrier, reducing oxidative reactions, preventing enzymatic browning, and preserving the fruit's color and texture. The PA/PE film, on the other hand, helped create a controlled internal atmosphere by reducing oxygen levels and increasing carbon dioxide, thereby slowing respiration and delaying ripening processes. This dual treatment not only minimized weight loss but also significantly extended the shelf-life of the fruit. The treated lychee exhibited a slower rate of maturity index decline, preserving both its sensory attributes and nutritional value for a longer period. The combination of the organic coating and modified-atmosphere packaging (MAP) proved to be an effective, eco-friendly solution for extending the shelf-life and maintaining the quality of lychee during cold storage. These findings offer a promising strategy for the sustainable preservation of fresh lychee, ensuring that it retains its visual appeal, flavor, and nutritional content during storage and transport.