*2.1. Fumigation and Fruit Treatment*

Longan fruit cv. Shixia were harvested from a commercial farm in the Guangxi region and transported to the laboratory. Fruit samples of uniform size and color with no defects were prepared. About 500 g of fruit was packed in oriented polypropylene (Jiahang OPP Packing Bag Co., Ltd., Jinhua, Zhejiang, China) of different thicknesses (OPP-20, OPP-40, OPP-60) and polyethylene (Bailiheng PE Packaging Bag Co., Ltd., Shenzhen, China) (PE-20, PE-40, PE-60) packages. A sterile gauze was fixed inside in each package, and 500 uL of the

propyl disulfide (a major volatile compound in neem (*Azadirachta indica*) seed; >99% Food grade, Aladdin Reagent Co., Ltd., Shanghai, China; Figure 1) was placed on the gauze to avoid its direct contact with the fruit. Each package was immediately sealed to reduce the evaporation of the compound from the bag. For comparison, fruit samples packaged in open net packages without propyl disulfide were considered the control treatment. All packages were stored at 12 ± 1 ◦C. The quality of the longan fruit was evaluated every third day using three bags (three replicates) from each treatment.

**Figure 1.** Structure of propyl disulfide.
