Abstract:To reduce the potential hazards of synthetic chemical preservatives (e.g., prochloraz and chlorine dioxide) on lychee (Litchi chinensis Sonn.) preservation and enhance its safety and quality, the preservation effects of the combined use of a compound plant-based preservative and preservation paper were analyzed. Lychees were treated with a compound preservative (CPP) alone, tea tree essential oil paper (TTP) alone, or a combination of CPP and TTP (CTP); untreated lychees served as the control (control check, CK) group. The treated lychees were stored at 4 ℃ for 21 days, during which appearance qualities, such as decay rate, nutritional qualities, such as anthocyanin content, metabolism of reactive oxygen species (ROS), such as superoxide dismutase (SOD), and activities of related enzymes, such as polyphenol oxidase (PPO), were assessed. The results showed significant differences in the decay rate between the CPP and TTP treatment groups and the CK group; CTP exerted the most potent inhibitory effect on lychee decay rate. After 12 days of storage, the anthocyanin content in the CPP, TTP, and CTP groups significantly increased by 34.67%, 68%, and 90.67%, respectively, compared with that in the CK group. After 21 days of storage, the malondialdehyde (MDA) content in the CPP, TTP, and CTP groups decreased by 47.22%, 56.83%, and 68.18%, respectively, compared with that in the CK group. During storage, the PPO activity in the CTP group was consistently lower than that in the CPP, TTP, and CK groups. In conclusion, combination treatment with CPP and TTP effectively mitigated the metabolism of ROS and reduced the activity of related enzymes, thereby maintaining the integrity of cell membranes and significantly delaying lychee browning. The combination treatment proposed in this study has thus demonstrated immense potential for application in lychee preservation.
