a-Amylase inhibition and inactivation in barley malt during cold starch hydrolysis

a-Amylase from barley malt decayed at a rate of 1.1% h at 45°C and this decay rate was greatly accelerated at 55°C. Glucose and maltose inhibited the catalytic actions of both bacterial and barley a-amylase in the same manner during the hydrolysis of starch granules. The catalytic activity dropped exponentially as these sugars increased up to 400 g/L; with about 50% activity at 100 g/L. Equations are presented to model both time decay of the enzyme and the inhibition effect of the sugars.