Enzyme and acid resistance of amylose-lipid complexes differing in amylose chain length, lipid and complexation temperature

Abstract

To study parameters that influence enzyme and acid resistance of amylose-lipid complexes, complexes were formed between amylose of different average chain lengths [Degree of Polymerisation (DP); DP60, 400, 950] and docosanoic acid (C22) or glyceryl monostearate (GMS) at 60 or 90 °C. Complexes were hydrolysed with hog pancreatic alpha-amylase or acid (2.2 N HCl). DP400- and DP950-complexes were of type I when formed at 60 °C and of type II when formed at 90 °C. Enzyme and acid resistance increased with increasing amylose DP, lipid chain length and complexation temperature. DP60 yielded only type I complexes, independent of the complexation temperature. Enzymic and acid hydrolysis of all complexes gave rise to two or more dextrin subpopulations, which are interpreted to originate from a sequence of lamellar units (the smallest peak DP) with interconnecting, amorphous amylose chains. The peak DP of such lamellar unit increased with increasing amylose DP and complexation temperature, but remained constant when higher enzyme dosages were applied. Synthesis of amylose-lipid complexes from amylose and lipids of variable structure under variable temperature conditions followed by hydrolysis can yield dextrin populations of defined and relatively narrow molecular weight distributions.