In vitro amylase hydrolysis of amylopectins from cereal starches based on molecular structure of amylopectins

摘要

To study the effects of the fine structures of APs on the enzymatic hydrolysis of wheat amylopectin (WA), maize amylopectin (MA) and waxy maize amylopectin (WMA), the relationship between the chain length distributions and enzymatic hydrolysis of amylopectins was established using high-performance anion-exchange chromatography, high performance liquid chromatography and logarithm of slope analysis (LOS). The results showed that WMA possessed a higher numbers of short-chains with a greater branch density, shorter average chain length and interblock chain length of amylopectin compare to WA and MA possessing a comparatively looser molecular structure. WA and MA were digested in two linear phases in the LOS plots, whereas WMA displays single phase. Whether using a-amylase alone (AA), or together with amyloglucosidase (AA/AMG), the k value of MA was slightly higher than that of WA in two-phase process, whereas the k value of WMA is far lower than that of WA and MA. Using AA alone, alpha-amylase releases very little glucose from WA, MA and WMA, the primary products of a-amylase being G2, G3 and G4. While together with AMG, the release of G1 significantly enhances. Using AA alone or AA/AMG, G6 and G7 from WA, MA and WMA are good hydrolytic substrates eventually reacting to yield G1 and G2 as the incubation time increases. (C) 2017 Elsevier Ltd. All rights reserved.