The Effect of Heat Treatment of the Nutritive Value and Hemagglutinating Activity of Soybean Oil Meal

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Abstract
A procedure for determining the hemagglutinating activity of soybean oil meals is described in detail. This method involves determination of the highest dilution of a saline extract of the soybean oil meal which will agglutinate the red blood cells of the rabbit under specified conditions. Previous digestion of the red blood cells with papain markedly enhances the sensitivity of this test. The decrease in hemagglutinating activity paralleled over a wide range the increase in the nutritive value of soybean protein effected by proper heat treatment. Although the use of either the untreated or papaintreated cells permitted a quantitative estimate of the degree of underheating of soybean oil meal, only the latter method was satisfactory for detecting samples which had been overheated. When the results of one test were considered in conjunction with those of the other, however, it was observed that optimally heated samples gave a negative reaction with the untreated cells and a positive reaction with the papaintreated cells. Underheated samples gave a positive and overheated samples a negative reaction with both types of cells. This rapid qualitative technique proved reliable in assessing the adequacy of heat treatment of 6 samples of commercial soybean oil meal which were tested.