The Effect of Radiation Sterilization on the Nutritive Value of Foods

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Abstract
The effect of irradiation sterilization and of heat cooking on the nutritive value of the protein in the fresh frozen garden pea and the lima bean was studied by the Thomas-Mitchell method. A 3 million or gamma irradiation was used to sterilize the frozen canned samples. No significant loss in nitrogen of the peas or beans resulted due to irradiation. The diet containing irradiated peas was found acceptable to the rat. Irradiation of the lima beans did not improve the poor consumption of the raw lima bean diet. Irradiation sterilization, like heat cooking, did not affect the digestibility of the raw pea protein (92%). While the biological value of the pea protein (58%) was also not affected by short-time cooking, irradiation sterilization with 3 million r dosage reduced it by 8%. The rats consumed the raw lima bean diets reluctantly, and heat cooking improved markedly the acceptability of these diets. Cooking also increased the digestibility by 9% and the biological value by 12%. On the other hand, irradiation of the raw lima beans with 3 or even 10 million r did not significantly improve the digestibility or the biological value of their protein. These findings are apparently the result of the trypsin inhibitor present in raw lima beans which thus appears to be destroyed by heat and not by irradiation. No difference in the nutritive value of the lima bean protein was found when the heat-cooked beans were compared with the irradiated and subsequently cooked lima beans. This indicates no damage to the lima bean protein due to irradiation.