HEAT INACTIVATION KINETICS OF TRYPSIN-INHIBITORS DURING HIGH-TEMPERATURE SHORT-TIME PROCESSING OF SOYMILK

Heat treatment of soymilk was studied in the conventional batch boilin g process and under High Temperature-Short Time (HTST) conditions. Red uction in total trypsin inhibitor was assayed enzymatically, and indiv idual inhibitors, the Kunitz and the Bowman-Birk inhibitor, were assay ed by ELISA technique. Standard first-order reaction kinetics and ther modynamics were applicable for inactivation, and results indicated tha t the mechanism was not protein unfolding, because entropy changes wer e zero or negative. The two inhibitors were inactivated at the same ra te around 137 degrees C. Therefore, a simple first-order kinetic model which gave a good, slightly conservative estimate of residual anti-tr ypsin activity under HTST conditions could be established.