61B-22 |
Production of off-odor volatiles from fatty acids and oils by irradiation |
E. J. LEE and D. U. Ahn. Animal Science Department, Iowa State University, 2373 Kildee Hall, Ames, IA 50011 Irradiation is the best-known method in controlling pathogenic microorganism in raw meat. But one of the major concerns associated with irradiating meat is off-odor production, which is related to free radical reactions. Previous studies indicated that irradiation increased lipid oxidation and total volatiles in raw and cooked meat. The objective of this study was to determine the volatile compounds produced from individual fatty acid by irradiation to understand the mechanisms involved in off-odor production in irradiated meat. Fatty acids generally found in meat (palmitoleic, oleic, linoleic, linolenic and arachidonic), and corn oil and refined fish oil were used in this study. Oil-in-water emulsion system was prepared and irradiated at 5 kGy. Volatile profiles, TBARS and odor characteristics of irradiated and nonirradiated oil emulsion were compared. 1-Hexene was generated in all irradiated fatty acids and the amounts of almost all cyclocarbon compounds were decreased after irradiation. Odor characteristic, however, was not changed much even the changes of volatile profiles after irradiation were significant. The result of TBARS during storage indicated that the rates of lipid oxidation in irradiated oil emulsions, especially those prepared with arachidonic acis, linolenic acid or fish oil, were faster than those of nonirradiated samples. The amounts of aldehydes, the best known-indicator for lipid oxidation, were increased linearly with storage time, but not significantly by irradiation. These results suggest that volatile compounds responsible for irradiation odor were different from those of lipid oxidation, which confirms our previous finding that volatile compounds produced from lipid oxidation had only a minor role in off-odor production in irradiated meat.
Session 61B, Food Chemistry: Flavor and aroma chemistry
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