Lipoxygenase activity of soybean and protein evaluation of soy milk produced from irradiated grains

Soybean and its derivative are considered as a functional food because it has high quality protein and are used for the prevention of chronic degenerative diseases. The irradiation technique is used in soybeans to increase shelf life and avoid problems in plant products consumed raw or processed. However, the controversy in the literature that the irradiation dose up 10 kGy food can alter the functional properties and structures of macronutrients. With the prospect of more information on the use of radiation on soybeans, the objective of this study was to determine the activity of lipoxygenase in soybeans and to evaluate possible changes in the protein content of soymilk processed from grain-BRS 213, BRS 258 and Embrapa 48 subjected to dosages of 2.5 , 5.0 and 10.0 kGy of gamma radiation. The soybean cultivars were wrapped in plastic bags and subjected to gamma radiation source 60Co, Gammacell 220 (Atomic Energy of Canada Ltd.), except the control. The grains irradiated induced reduction of enzyme activity. The results for the protein content of soymilk were similar, appropriate to that required by ANVISA and showed little protein solubility for cultivars BRS-258 and Embrapa48. It was concluded that the technique of irradiation beyond to keep the nutritional value of soy can contribute to the organoleptic quality of soymilk. (author)