This study was to investigate the chemical composition and the antioxidant activity of essential oils extracted from Torreya grandis cv. merrillii arils by hydro-distillation. Eighty six compounds, accounting for 96.39% of the essential oil, were identified by GC-MS. The essential oil contained 42 sesquiterpenoids (68.91%), 25 monoterpenoids (14.52%), 14 diterpenoids (12.39%), 3 ester (0.35%), 1 aliphatic ketones (0.04 %), and 1 aliphatic aldehyde (0.18%). The major components of the oil were Δ-cadinene, germacrene D, limonene, β-farnesene, cembrene, and α-pinene. Antioxidant activities of the essential oil was determined by 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity assay (IC50=17.13 mg/ml), β-carotene/ linoleic acid bleaching method (IC50=22.48 mg/ml), and thiobarbituric acid reactive species assay (IC50=13.48 mg/ml). These various antioxidant activities were compared with synthetic antioxidants (butylated hydroxytoluene and acorbic acid). Restults revealed that the essential oil possessed strong antioxidant activity, suggesting that the arils of Torreya grandis cv. Merrillii could be a bio-resource for an essential oil with antioxidant activity.
Loquat is a nutrient-rich fruit with juicy and sweet pulp, but it is vulnerable to rot and deterioration without proper postharvest preservation measures. This study aimed to improve the postharvest quality of loquat by developing a microemulsion system based on an essential oil extracted from theTorreya grandiscv. Merrillii aril (TaEO), which has antimicrobial and antioxidant properties. An optimal TaEO microemulsion (TaEO-ME) was formulated, using a mixture of Tween-40 and Tween-80 as the surfactant, 1-butanol as the co-surfactant, and TaEO as the oil phase, with mass ratios of 9:1, 3:1, and 6:1, respectively. Two TaEO-ME formulations with 60% and 70% water contents were stable for 180 days at room temperature, with a mean droplet size below 12 nm and polydispersity index less than 0.24. They also exhibited higher stability and enhanced biological activities compared to free TaEO. Loquat fruit treated with TaEO-ME displayed a reduced decay index and lower membrane lipid peroxidation after 15 days of storage at 15 °C, as indicated by the lower malondialdehyde content and higher peroxidase activity. Moreover, the TaEO-ME treatment preserved the nutrient quality by maintaining the total phenolic compounds and ascorbic acid content. Our findings suggested that TaEO-ME can be used as a substitute for chemical preservatives to keep fruits fresh.Keywords:microemulsion;Torreya grandiscv. Merrillii aril;essential oil;loquat;fruit quality
危险品化学品经营许可证（带存储）