Effect of thermal treatments and ???￡-irradiation on volatile and non-volatile Egyptian anise essential oil and its antioxidant properties

摘要

Effect of thermal treatments; electric oven, microwave and ?-irradiation, at 6, 8, and 10 kGy, on composition of volatile and non-volatile anise essential oil was studied. Volatile profile of raw hydrodistilled anise oil mainly consists of E-anethole (79.68 %), hexahydrofarnesyl acetone (6.95 %), p-anisaldehyde (5.49 %), ?-himachalene (2.53 %) and estragole (0.76 %). Remarkable decrease of phenylpropanoids was observed in 6 and 8 kGy ?-irradiated samples. All samples revealed high antioxidant activities. Thermal and ?-irradiation showed high increase in total sesquiterpenes yield. Oxygenated compounds yield diminished, which significantly affected antioxidant activity. 8 kGy ?-Irradiated sample exhibited the strongest reducing effect on DPPH? (84.57 %) and the highest inhibiting effect of linoleic acid (85.21 %) and subsequent bleaching of a-carotene, compared to bulylated hydroxytoluene (98 %). 9 Phenolic compounds were identified using HPLC and C18 RP-HPLC techniques. The predominant components are p-qumaric acid (43.36 %) and ferulic acid (21.06 %).