“Studies on the Effect of Thermal and Radiation Treatments Using Microwave and γ-Irradiation on the Volatile Oil Components and Antioxidant Activity of Some Herbs and Spices”

Abstract

The effect of various thermal treatments (electric oven, microwave) and γ-irradiation at three doses (6, 8 and 10 KGy) on composition of volatile component of Anise (Pimpinella anisum L.) ; Fennel (Feniculum vulgare mill) and Black cumin (Nigella sative L.) essential oil of seeds and also on their antioxidant properties were studied. The hydrodistilled oil (HD) of control and treated samples of each spice were subjected to gas chromatography-mass spectrometry (GS/MS) analysis. Eighteen volatile compounds were identified in HD oil of anise of all treated samples. These compounds are 4 phenylpropanoid derivatives, 9 sesquiterpenes and 5 oxygenated terpenoids. The volatile profile of row HD oil of anise consisted mainly of trans-anethole (79.86%) followed by hexahydofarnesylacetone (6.95%); ρ-anisaldehyde (5.49%); γ-himachalene (2.53%); and estragole (0.76%). Although the effect of roasting didn’t cause significant changes in the total yield of major compounds of HD anise oil which are phenylpropanoid derivatives (E-anethol, ρ-anisaldehyde, Z-anethole and estragole), it is found that γ-irradiation revealed the same behavior at 10 KGy but decrease the total yield of these compounds in 6,8 KGy irradiated samples compared to control one.