The nutritive value for chicks of full-fat soybeans irradiated at up to 60 kGy

Samples of full-fat soybean were tested for nutritional value after being irradiated at dose levels 5, 15, 30, and 60 kGy. The gross composition of raw and irradiated beans was similar. Available lysine was reduced by 2.8%, 4.4% and 5.5% when seeds were irradiated at 15, 30, and 60 kGy, respectively. Trypsin inhibitor activity decreased linearly from 35.9 to 9.9 TIU g−1 of sample as a function of radiation dose. Haemagglutinating activity of beans processed at 5 kGy showed no significant change while in those processed at 15, 30, and 60 kGy the haemagglutinating activity was reduced by 50%, 75%, and 93.8%, respectively. Urease activity was also decreased as a function of radiation dose. The total protein efficiency (TPE) of processed beans at the doses applied was increased by 23%, 41.5%, 74.6% and 95.7%, respectively, as compared with the value for raw beans. The data show that 60 kGy resulted in deactivation of antinutritional factors and improved the TPE by 96%. It was concluded that irradiation contributed to optimal processing conditions of full-fat soybeans for chick diets.