Abstract
Changes of disc electrophoretic and ultracentrifugal patterns of soybean protein by heating were different, depending on whether the protein is in soybean milk or in acid precipitated protein solution. It was revealed that ionic strength has definite effects on these changes, and this is why the changes are different between soybean milk and acid precipitated protein solution. 7S protein is sensitive to heating at higher ionic strengths, forming aggregates directly, whereas 11S protein is sensitive at lower ionic strengths, dissociating to subunits which form aggregates partly. The fact that 7S protein cannot form firm gel by glucono-delta-lactone after heating and 11S protein can form firm gel when reasonably heated is supposed to be attributed to the difference of the process of aggregates formation during heating between the two proteins.
