Comparative Study on the Changes in Volatile Flavor Compounds of Dried Leeks (Allium tuberosum R.) by γ-Irradiation

Abstract

This study was performed to examine the effect of γ-irradiation on the volatile flavor compounds of dried leeks (Allium tuberosum R.). Volatile compounds from dried leeks were extracted using simultaneous steam distillation and extraction (SDE) method and analyzed by gas chromatograph/ mass spectrometry (GC/MS). 41 and 42 Compounds were identified in non-irradiated and irradiated at 10 kGy, respectively. These compounds included alcohols, aldehydes, esters, S-containing compounds, N-containing compounds and miscellaneous. The characteristic flavor compounds of irradiated dried leeks were similar to those of non-irradiated samples but the intensities of the peaks were obviously different between them. S-containing compounds were found as dominant compounds in the both of these samples but their amounts were decreased after γ-irradiation in comparison with control. Among S-compounds, dimethyl disulfide, (Z)-propenyl maethyl disulfide, methyl allyl disulfide, (E)-propenyl methyl disulfide, dimethyl trisulfide, 3-ethyl-1,2-dithi-5-ene, (Z)-methyl propenyl trisulfide and (E)-methyl propenyl trisulfide were dramatically decreased after irradiation. This investigation indicates that the numbers of volatile compounds in the irradiated dried leeks were increased as compared to non-irradiated sample but the quantities of major volatile compounds were decreased losses by irradiation.