ADSORPTION OF ALPHA-AMYLASE ON HEAT-MOISTURE TREATED STARCH

The adsorption characteristics of heat-moisture treated starch for alp ha-amylase was studied. Adsorption was improved by adding ethanol (to 30% v/v). When the starch was pre-hydrolyzed by alpha-amylase, adsorpt ion was greatly decreased. It was found that the addition of ethanol t o heat-moisture treated starch induces the formation of a region which escapes enzymatic digestion and, although a small amount by weight, h as a high adsorption potential for alpha-amylase. In an evaluation usi ng the Langmuir equation, this region was found to have a large surfac e area. The addition of ethanol brought about a decrease in two parame ters, Vm(app) and Km(app) of the Michaelis-Menten equation, for the en zymatic hydrolysis of heat-moisture treated starch. (C) 1996 Academic Press Limited