Physicochemical properties of high-amylose maize starch

【Objective】High-amylose maize starch is an important industrial raw material.This study investigated its physicochemical properties to improve the cultivation of new varieties and industrial exploitation.【Method】Using thirteen high-amylose maize inbreds and one common inbred(Zheng 58),the differences in phenotypic characteristics of starch granules,thermal properties,pasting properties,solubility and expansion power of high-amylose maize starch and normal maize starch were investigated.【Result】The amylose content of common maize inbred starch was 27.72%.The amylose content of high-amylose maize inbred starch was 44.22%-78.81%,and could be divided into four levels.According to scanning electron micrographs,A-type starch granules from common inbred were full and smooth spheres or polyhedrons with waxy luster but those from high-amylose maize inbred were shrunken irregular and dull polyhed-rons.There were also significant differences in B-type starch granules and full and smooth spheres gradually changed to dull ovals,even to distorted irregular shapes.With increase of amylose content,To,Tp,Tc and To-Tc gradually increased butΔHgradually reduced.The pasting properties(RVA)of common inbred starch showed typicaldoubletscurve,while that of high-amylose maize inbred starch showedScurve with the increase of amylose content.The melting curves and expansion curves of common inbred starch and high-amylose maize inbred starch showed same trends,while starch solubility and swelling degree decreased significantly with the increase of amylose content.【Conclusion】Compared to common corn starch,high-amylose corn starch was different in the phenotypic characteristics of starch granules,thermal properties,pasting properties,solubility and swelling power.The difference increased as the increase of amylose content.