Abstract:This study investigated the in vitro antioxidant activity and preservative effect at ambient temperature of Longan seed essential oil. Longan seed essential oil was extracted with organic solvent n-hexane for the determination of 1, 1-diphenyl-2-picrylyl (DPPH·) free radical,hydroxyl radicals (·OH) and sodium nitrite (NaNO2) scavenging abilities. The preservative effects were assessed based on the changes in physiological indices including Longan flesh color, peel browning index, weight loss rate, soluble solids content and titratable acidity. The results showed that the Longan seed essential oil exhibited detectable DPPH·, ·OH and NaNO2 scavenging activities, with respective IC50 values as 11.04, 4.58 and 0.12 mg/ mL, and a dose-effect relationship was found within the experimental concentration range. The essential oil can reduce peel browning index and weight loss rate of Longan peel; the change in the soluble solid content was small; the titratable acidity changed slowly in the early stage of storage, but increased rapidly in late stage. There was no significant difference (P ＞ 0.05) between the essential oil-treated group and the control (untreated) group. The Longan seed essential oil did not exert obvious preservative effect on Longan fruit. Excessive essential oil could also cause different degrees of phytotoxicity to Longan fruit.
