Some factors affecting the haemagglutinin of soybean

The water extract of unheated defatted ground soybean (soybean meal) contained haemagglutinin activity 7137 units per g soybean meal and carbohydrate content 6.34 g per 100 g soybean meal. After adjusting the pH-value of the water extract to pH 4.4, and centrifuging it, the supernatant contained most of the carbohydrate content (6.27 g per 100 g soybean meal), while noticeable decrease in the haemagglutinin was found. The DEAE-cellulose chromatography of the acetone precipitate from the water extract of soybean meal gave five protein peaks. The first four peaks showed the presence of haemagglutinin and about 40% of the total haemagglutinin were present in the first peak. The haemagglutinin activity of the water extract of soybean meal was measured at different temperatures for different intervals. The activity was easily affected by the heat treatment and it was destroyed completely after five minutes by heating at 100 ‡C and the activation energy was 9.45–10.26 kcal/mole.