5005
Engy Mahmoud Mohamed Mahmoud
“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
Anise oil, fennel oil and black cumin oil, thermal processing, γ-irradiation, antioxidant, volatile and non-volatile
Anise (Pimpinella anisum L.) ; Fennel (Feniculum vulgare mill) and Black cumin (Nigella sative L.) seeds were subjected to roasted by thermal treatment (electric oven, microwave) and γ-irradiation at three doses and evaluate the effect of these treatments on the composition of volatile and non-volatile as well as on their antioxidant activity of each spice. The hydrodistilled oil (HD) of control and treated samples of each spice were subjected to gas chromatography-mass spectrometry (GS/MS) analysis. 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 it cause drastic increase in the total yield of sesquiterpenes whereas decrease oxygenated compounds in all roasted sample compared to control one. The strongest effect of reduction of DPPH radical as well as the highest inhibiting effect of the oxidation of linoleic acid and the subsequent bleaching of β-carotene was by 8KGy irradiated. Also 8 KGy irradiated sample was chosen as the selected sample for HPLC analysis, since 9 non volatile phenolic compound were identified. Roasting cause a drastic increase in the total yield of phenylpropanoid (major compounds) in all treated samples of fennel by thermal or by γ-irradiation ranging from (82.12%) in electric oven roasted sample to (89.63%) in 10 KGy irradiated sample compared to (72.67%) in control one. Also Roasting cause a decrease in the total yield of phenyl propanoid. It cause a remarkable decrease in the total yield of monoterpenes and oxygenated terpenes in HD oil of all treated fennel sample compared to row sample. The strongest effect of DPPH radical as well as β- carotene bleaching assay was by microwave roasted sample. Microwave roasted sample was the selected sample for HPLC analysis which revealed 14 polyphenolic compound were identified. The volatile profile of row HD oil of black cumin consisted mainly of thymoquinone (41.76%) followed by γ-Cadinene (10.80%); davanone (10.06%); α-cadinene (8.33%); thymohydroquinone (6.12%); isopropyl myristate (3.03%); longifolen (2.18%); thymol(2.59%) and carvacrol (1.62%). Microwave roasted sample was the selected sample for HPLC analysis A total 11 phenolic compounds were identified
2015
M.Sc
Ain Shams
Science