目的 为了延长荔枝在常温下的货架期。方法 制备一种具有3层结构的可持续释放SO2杀菌剂的复合膜，将复合膜热封成保鲜包装袋，并以“桂味”荔枝为实验对象，以裸放组和市售食品保鲜袋处理组为对照组，研究保鲜包装袋在常温下对荔枝的保鲜效果。分析荔枝在贮藏期间的质量损失率、褐变指数、好果率、可溶性固形物含量及可滴定酸含量的变化。结果 在常温下，裸放的荔枝和用市售保鲜袋包裹的荔枝在货架期第2—3天就会发生严重褐变，失去商业价值。用自制的可释放适量SO2的保鲜袋贮藏荔枝时，在货架期第6天时，质量损失率仅为2.44%，褐变指数仅为1.26，可溶性固形物和可滴定酸质量分数分别为18.6%，0.18%，好果率仍达到88.33%。结论 可释放SO2的保鲜包装袋能减少荔枝水分损失，抑制褐变，保持荔枝的风味和口感，提高荔枝的商业价值，在常温下将荔枝的货架期延长至6 d左右。

The work aims to extend the shelf life of litchi under room temperature. A composite film with a three-layer structure was prepared for sustainable release of SO2 fungicide. The composite film was heat-sealed into the fresh-keeping packaging bags, and the "Guiwei" litchi was used as the experimental object. The naked group and the market food fresh-keeping bags were used as the control group. The effect of fresh-keeping packaging bags on litchi at room temperature was studied. The changes in mass loss rate, browning index, good fruit rate, soluble solids content and titratable acid content of litchi during storage were analyzed. The litchi exposed at room temperature and wrapped in market fresh-keeping bags would become browning severely and lose its commercial value during the shelf life of 2—3 days. When the litchi was stored in self-made fresh-keeping bags with releasable SO2, on the 6th day of the shelf life, the mass loss rate was only 2.44%, the browning index was only 1.26, the contents of soluble solids and titratable acid were 18.6% and 0.18%, respectively, and the good fruit rate was still 88.33%. The fresh-keeping packaging bags with releasable SO2 can reduce water loss, inhibit browning, maintain the flavor and taste, improve the commercial value and extend the shelf life of litchi to about 6 days at room temperature.