Hydrocarbons detected in irradiated and heat-treated eggs

Shell eggs were non-irradiated or irradiated at 0.5, 1 and 3 kGy, and boile d, fried or heated in ovens. Hydrocarbons were determined by a sequential p rocedure of lipid extraction by hexane, Florisil column chromatography and gas chromatography. Hydrocarbons 15:0, 14:1. 17:0. 16:1, 17:1, 16:2. 17:2 a nd 16:3 were detected in shell eggs irradiated at 0.5 kGv or higher, but no t in nonirradiated ones except 15:0 and 17.0. Boiling non-irradiated or irr adiated eggs for 40 min little affected detection levels of the hydrocarbon s. Frying the egg yolk of the non-irradiated eggs for 5 min produced hydroc arbons 17:1 and 17:2 besides 15:0 and 17.0. Hydrocarbons 15:0, 17:0, 17:1, 17:2, 14:1 and 16:1 were detected in the egg yolk of the non-irradiated egg s while heating it in a cooking oven at 170 degreesC for 60 min. The patter n of hydrocarbons detected in non-irradiated samples when heated was, howev er, notably different from that of irradiated ones: detection of hydrocarbo ns in shell eggs or egg products could, thus, identify their post-irradiati on. (C) 2001 Elsevier Science Ltd. All rights reserved.