| Irradiation is one of the food preservation methods to preserve quality against undesirable microbial, physical, chemical or biochemical actions. However, chemical changes can be expected in irradiated foods with increasing radiation dose. The specific doses used to irradiate food depend on the objectives of the process and thus various products would be formed as a result of radiolysis during irradiation. The chemical changes in food systems during processing are very complex phenomena. Hence, the use of food model systems contributes to the understanding of the chemical/volatile changes due to irradiation at specific doses. Therefore, the objectives of this study were to determine the effect of irradiation on various model food systems (lipid, protein and carbohydrate), correlation between possible changes and applied radiation dose, and to compare specific patterns of observed chemical changes in model food systems with natural food systems.;Different fatty acids, canola oil and unrefined canola oil were irradiated at different doses (1 kGy, 10 kGy and 20 kGy) and were analyzed for changes in color, fatty acid constituents and volatiles. A significant change in color was detected in canola and unrefined canola oils. There were no changes in pure fatty acids and canola oil fatty acid profiles, irrespective of dose and type of fatty acids. The effect of irradiation was not detected by gas chromatography on the major components of fatty acids, canola oil and unrefined canola oil. However, minor constituents of fatty acids, canola oil and unrefined canola oil volatiles were affected by irradiation at 1 kGy, 10 kGy and 20 kGy. The volatile compounds generated at same doses in different fatty acids, canola oil and unrefined canola oil were tentatively identified by GC/MS.;Similarly, casein and non-fat dry milk solutions were irradiated at 1 kGy, 10 kGy and 20 kGy and analysed for their color and protein constituents. In the presence of water, proteins underwent radiolysis producing radiolytic products depending upon irradiation doses and structure of the molecules. Thus, irradiation had more effect on the minor constituents than the major constituents of proteins.;Fructose, sugar, starch and rice also were irradiated in the presence of water at doses of 1 kGy, 10 kGy and 20 kGy. The irradiated samples were analysed for their carbohydrate constituents and color. A significant reduction of pH was observed with fructose, sugar, starch and rice with increasing irradiation doses. Also, fragmentation of carbohydrate into smaller molecules was detected. The breaking of large molecules depended upon irradiation doses and the structure of the carbohydrate.;With all lipids, proteins and carbohydrates, the presence of other macronutrients had no effect on the irradiation protection compared to the pure form of lipids, proteins and carbohydrates. |
