E ssential oil from coriander fruits (Coriandrum sativum L.) is widely used in the food, perfumery, and pharmaceutical industries. Farag and El Khawas (1996) found that irradiation dose 5 and 10 kGy on black pepper, anise, fennel, turmeric and coriander have an effective decontamination treatment but there were losses of flavor components observed, particularly at the higher dose (10 kGy). Effect of Gamma Irradiation and Method of Extraction on the Essential Oil Composition Extracted from Coriander Fruits C oriander fruits essential oil obtained by SFE presents some quantitative and qualitative differences that give a superior aroma (increasing oxygenated compounds which have the aroma characteristics in essential oils) compared with oil obtained by steam distillation. Linalool is increased due to irradiation treatment. Meanwhile, some components are appeared in the essential oil of coriander due to irradiation process. Farag, R.S. and El Khawas, K.H.A.M. (1996). Influence of gamma irradiation and microwaves on the antioxidant property of some essential oils. Advances in food science, 18, Grosso, C.; Ferraro, V.; Figueiredo, A.C.; Barroso, J.G.; Coelho, J.A. and Palarva, A.M. (2008). Supercritical carbon dioxide extraction of volatile oil from Italian coriander seeds. Food Chemistry, 111, Kubeczka, K. H. (2002). “Essential oil analysis: by capillary gas chromatography and carbon-13 NMR spectroscopy”.2 nd, completely rev., Ed. Published by John Wiley & Sons, Ltd. Baffins Lane, Chichester, West Sussex, PO19IUD, England. Masada, Y. (1980). “Analysis of essential oil by gas chromatography and mass spectrometry”. Published by John Wiley & Sons. Inc. New York, London, Sydeny and Toronto. Misharina, T. A. (2001). Influence of the Duration and Conditions of Storage on the Composition of the Essential Oil from Coriander Seeds. Applied Biochemistry and Microbiology, 37, (6): Irradiation treatment: C oriander fruits and its essential oils were exposed to gamma irradiation at dose 4 kGy for each, using 60 Co Russian gamma chamber, (dose rate 3.7 kGy/hr), in Cyclotron Project, Nuclear Research Center, Atomic Energy Authority, Abou-Zaabal, Egypt. The major chemical component of coriander fruit essential oil, namely linalool (57.21 %) was increased by % and 5.3 % in the oils of irradiated coriander fruits (63.69%) and irradiated essential oil (60.24%), respectively (Masada, 1980; Kubeczka, 2002 and Grosso et al., 2008 ). INTRODUCTION MATERIALS and METHODS Restrictor Co 2 sample cell in heated chamber Co 2 Trap Solid or Liquid Modifier Pump Co 2 Pump (High pressure) Co 2 Pump (High pressure) Liquid Carbon Dioxide (requires a dip tube) Indian European A. Z. M. Badee *, A. T. El-Akel *, A. H. Rady ** and M. A. Abdelaleem ** * Food Science Department, Faculty of Agriculture, Cairo University. ** Nuclear Research Center, Atomic Energy Authority, Abou-Zaabal, P.N.13759, Egypt. Gas Chromatography-Mass Spectrometry: GC Model (TRACE GC 2000 produced by THERMO) was used. DB-5 column (30m x 0.25mm i.d, 0.25 μm film thickness) was used with helium (20 cm/sec) as the carrier gas (4.5 psi). CONCLUSION REFRENCES RESULTS and DISCUSSION Relative Abundance Time (min.) Relative Abundance Time (min.) Relative Abundance Time (min.) Coriander Fruits Essential Oil Obtained by SD (unirradiated) Essential oil Obtained from Irradiated Coriander Fruits Irradiated Essential Oil Obtained from Unirradiated Coriander Fruits Coriander Fruits Essential Oil Obtained by SFE Linalool (57.21%) Linalool (57.21%) Linalool (63.69%) Linalool (63.69%) Linalool (60.24%) Linalool (60.24%) Linalool (79.47%) Linalool (79.47%) α- pinene (8.05%) α- pinene (8.05%) α- pinene (5.54%) α- pinene (5.54%) α- pinene (6.92%) α- pinene (6.92%) α- pinene (0.84%) α- pinene (0.84%) γ-Terpinene (6.61%) γ-Terpinene (6.61%) γ-Terpinene (10.19%) γ-Terpinene (10.19%) γ-Terpinene (6.87%) γ-Terpinene (6.87%) γ-Terpinene (1.12%) γ-Terpinene (1.12%) T here are 41, 40, 40 and 40 components were isolated and identified in coriander fruits essential oil (unirradiated and extracted by steam distillation), essential oil obtained from irradiated coriander, irradiated essential oil and coriander fruits essential oil obtained from supercritical fluid extraction, respectively. Irradiation of coriander fruits or their essential oil with 4 kGy led to complete loss of the aromatic alcohols (ρ-cymene-8-ol) in both oils. aromatic hydrocarbons suffer from partially loss of its unique component (ρ-cymene) due to irradiation of coriander fruits and their essential oil. Δ3-carene appeared in both coriander oil of irradiated fruits and irradiated oil, while β-ocimene developed after irradiation of coriander fruits, but not detected in the irradiated essential oil. Moreover, α-citronellol was appeared only after irradiation of both of coriander fruits and their essential oil (Misharina, 2001). T here were many compounds, which were completely disappeared during the supercritical fluid extraction (SFE). These compounds are mostly hydrocarbon terpenes such as aliphatic terpene group besides, terpene aldehydes, aromatic hydrocarbon and aromatic alcohols groups, especially the components having low beaks, such as β-myrcene,  -thujene and  -terpinene. Meanwhile, linalool is increased from 57.21% to 79.47% and camphor from 4.75 % to 5.08 %. Coriander flower Camphor (4.75%) Camphor (4.75%) Camphor (3.36%) Camphor (3.36%) Camphor (4.36%) Camphor (4.36%) Geranyl acetate (4.82%) Camphor (5.08%) Camphor (5.08%) Geranyl acetate (2.03%) Geranyl acetate (5.70%) Geranyl acetate (3,59%)