Effect of starch on the inactivation of amylase in starch-containing foods

Abstract

The quality of starch-containing foods is significantly impaired by contamination with small amounts of α-amylase, which hydrolyzes the starch and causes viscosity loss. We examined the effect of different temperatures and times on inactivation of ¿-amylase in starch-containing foods. Model foods containing a known amount of human salivary α-amylase (HSA) were incubated at temperatures from 60 to 80°c for 30 min. In the case of a 3% starch suspension incubated at 70°c, it took 10 min before the viscosity loss ceased, by which time the viscosity was halved. In 0.1 . 3% starch suspensions at pH 5.5, the inactivation of HSA could be described by a first order kinetic model. The presence of starch decreased the inactivation rate constant by decreasing the Arrhenius frequency factor. To prevent viscosity loss by α-amylase contamination in starch-containing foods, the inactivation time and temperature should be increased with increasing concentration of starch.