Irradiation does not considerably raise the temperature of the food and nutrient losses are small and often significant as compared to other methods of preservation such as canning, drying and heat pasteurization.
Macronutrients like carbohydrates, proteins, and fats, undergo little change during irradiation even at doses over 10 kGy. Similarly, the essential amino acids, minerals, trace elements and most vitamins do not suffer significant losses.
Different types of vitamins have varied sensitivity to irradiation and it depends on the complexity of the food system and the solubility of the vitamins in water or fat. Vitamin losses can be minimized by irradiating the food in frozen form or by packaging it in an inert atmosphere such as under nitrogen. Four vitamins are recognized as being highly sensitive to irradiation: B1, C (ascorbic acid), A (retinol) and E (alpha-tocopherol). However, B1 is even more sensitive to heat than to irradiation.
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