STUDIES ON THE DEGRADATION OF MAILLARD-PR ODUCTS BY AMYLOLYTIC ENZYMES .3. INHIBITION OF GLUCOAMYLASE, ALPHA-AMYLASE AND ALPHA-GLUCOSIDASE BY HEAT-TREATED ALPHA-GLUCANES AND MELANOIDINES

Amylolytic enzymes are only slightly inhibited by thermal treated alph a-glucans (10-15 %). The addition of glycine to the thermolysis mixtur e produces no increase of the inhibition. The inhibition of the enzyme activity is probably caused by short-chain alpha-glucans that the sec ondary binding places of the active centre coat and therefore the hydr olysis is reduced. Glucoamylase and alpha-amylase are not inhibited by non-dialysed melanoidines from the reaction of D-glucose and glycine, but there is a strong inhibition of alpha-glucosidase by these melano idines (up to 45 %). Strongly coloured, low molecular compounds that a re formed during the Maillard-reaction and are soluble in ethyl acetat e cause no inhibition of Glucoamylase and alpha-amylase.