67C-9 |
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K. T. HWANG, Food Science & Human Nutrition, Chonbuk National University, Jeonju, Jeonbuk, 561-756, South Korea, J. E. Kim, and J. S. Yang, Radiation Application Group, Korea Atomic Energy Research Institute, 150 Duckjin-Dong, Yuseong-Gu, Daejeon, 305-353, South Korea. Irradiation of soybeans is allowed maximally up to 10 kGy as soybean products, soya powder and soya flour with the purpose of disinfestation or microbial control in some countries. Detection of hydrocarbons is one of promising methods to identify post-irradiation of foods containing fats. Detection of hydrocarbons in animal-origin foods has been studied more extensively than plant foods. The objective was to determine major hydrocarbons in irradiated and roasted soybeans and soybean powder. Soybeans were irradiated (Irr), irradiated and roasted (Irr-Rst), roasted and irradiated (Rst-Irr), roasted, ground and irradiated (Rst-Grd-Irr), and irradiated, roasted and ground (Irr-Rst-Grd). The fat was extracted using hexane and Na2SO4. Hydrocarbon fraction was separated through Florisil column and analyzed using GC. Hydrocarbons C17:2, C16:3, C17:1 and C16:2 were not detected in non-irradiated soybeans and soybean powder, but were detected in those irradiated at 0.5 kGy or higher. The levels of the hydrocarbons increased with dose. C17:2, C16:3, C17:1 and C16:2 detected in the Irr at 10 kGy were 9.16, 8.82, 5.32 and 5.32 mg/g fat, respectively. The pattern of the hydrocarbons detected in the Irr-Rst and Rst-Irr was little different from that in the Irr. The levels of C17:2 and C17:1 in the Rst-Irr at 10 kGy were significantly higher than those in the Irr (p<0.05). The amounts and types of hydrocarbons detected in the Rst-Grd-Irr and Irr-Rst-Grd were similar to those in the Irr, Irr-Rst and Rst-Irr, except that C17:2 and C17:1 in the Rst-Grd-Irr were remarkably lower than those in the soybean groups. C17:2 and C17:1 in the Rst-Grd-Irr were significantly lower than those in the Irr-Rst-Grd (p<0.05). These results suggest that the prominent radiation-induced hydrocarbons C17:2, C16:3, C17:1 and C16:2 can be used as markers for identifying post-irradiation of soybeans even with physical treatments such as roasting and grinding.
Session 67C, Food Chemistry: Food analysis, irradiation and toxicology
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