EFFECT OF PH AND PROTEIN-CONCENTRATION ON RHEOLOGICAL BEHAVIOR OF ACIDIC SOYBEAN PROTEIN GELS

Heat-induced gels of different pH and protein concentration were obtai ned from pH 3.25 and 8.0 soybean isolates. Viscoelasticity and, textur e behavior of the gels were analyzed by dynamic rheological assays and uniaxial compression tests. Results indicate that soybean protein dis persions exhibit a viscoelastic behavior. At low protein concentration , the acidic dispersions behave as pseudogels. Elasticity and resistan ce to deformation increase, and fracturability and hardness decrease a s pH decreases. Acidic gels of high protein concentration behave as st rong or true gels. The latter show elasticity, fracturability, hardnes s, and resistance to deformation prior to rupture values higher than l ow protein concentration gels.