REDUCTION OF RADIATION-INDUCED VITAMIN LOSSES BY IRRADIATION OF FOODSTUFFS AT LOW-TEMPERATURES AND BY EXCLUSION OF ATMOSPHERIC OXYGEN

The protective effect of low temperatures during irradiation on vitamin B, and E levels in foods is not abolished by subsequent storage or heating. Egg powder irradiated at 1 Mrad in the presence of air and stored for 4 months at ambient temperature lost 68% of its thiamin content when irradiated at 20 °C, 33% when irradiated at -30 °C. Sunflower oil irradiated at 3 Mrad in the presence of air and subsequently heated for 1 hour at 180 °C lost 98% of its α-tocopherol content when irradiated at 20 °C, 65% when irradiated at - 30 °C. Exclusion of atmospheric oxygen by packaging under nitrogen reduced the loss of α-tocopherol in irradiated (0.1 Mrad) rolled oats after 8 months of storage from 56 to 5% and the loss of thiamin from 86 to 26%. Vacuum packaging was equally effective during the first 3 months and somewhat less effective during the following 5 months. Packaging under carbon dioxide showed no advantage over packaging in air. Sensory evaluation of rolled oats, raw or cooked, 1 and 3 months after irradiation with 0.1 Mrad indicated no significant quality difference between unirradiated and irradiated samples packaged under nitrogen. © 1979 J. F. Bergmann Verlag.