HEAT INACTIVATION OF TRYPSIN-INHIBITORS IN SOYMILK AT ULTRA-HIGH TEMPERATURES

Soymilk samples at pH 7.5, 6.5 and 2 were subjected to heat treatment at 93-degrees-C and indirect ultra-high temperature. When heated at 93 -degrees-C, 121-degrees-C and 132-degrees-C, trypsin inhibitor activit y (TIA) in soymilk was more heat-labile at high pH than at lower pH. H owever, the effect of pH on rate of thermal inactivation was less pron ounced when the holding temperature was increased to 143-degrees-C and 154-degrees-C. The point on a curve relating holding temperature and holding time, indicating inactivation of 90% of the TIA in soymilk at pH 6.5 in the range 93-154-degrees-C, coincided with the thermal-death -time curve of the organism putre-factive anaerobe 3679 at about 125-d egrees-C.