THERMAL GELATION OF TRYPSIN HYDROLYSATES OF SUNFLOWER PROTEINS - EFFECT OF PH, PROTEIN-CONCENTRATION, AND HYDROLYSIS DEGREE

The influence of several parameters on the gelation properties of tryp sin hydrolysates of sunflower proteins was studied by dynamic rheologi cal methods. The degree of hydrolysis has very little effect on either storage modulus or gelation time. Sunflower protein gelation is stron gly pH dependent. Gelation is only possible in the pH range 7-11. The storage modulus reaches its maximum value at pH 8. The gels formed at pH 7 or above pH 9 are very weak. Gelation time increases with pH and decreases with protein concentration. The storage modulus at pH 8 incr eases exponentially with protein concentration. The exponent of the la w relating storage modulus to protein concentration changes from about 8 in the range 1.7-2.5% to 2 at concentrations >3.5%. The critical pr otein concentration is <1.1%.