Effects of temperature‐cycled retrogradation on properties of amylosucrase‐treated waxy corn starch

Abstract

Background and objectivesThough amylosucrase (AS)‐treated starches have been studied recently, the retrogradation properties of AS‐treated starches have not been studied yet. In this study, AS‐treated waxy corn starch was retrograded by temperature cycling, and the effects of storage conditions on the structure and digestibility of the starch were investigated.FindingsAmylosucrase‐treated waxy corn starch had a larger amount of long chains (degree of polymerization ≥25) than the control starch and exhibited amylose‐like behavior. Temperature cycling induced the reassociation of the elongated chains of AS‐treated starch and accelerated retrogradation, causing rapid and significant increases (p < 0.05) in melting enthalpy, relative crystallinity, and resistant starch (RS) content compared to those observed during isothermal storage.ConclusionsStructural changes affected the reassociation and/or melting properties of starch, as the two starches (control starch and AS‐treated starch) had different favored steps of retrogradation (propagation and nucleation, respectively) during temperature‐cycling storage.Significance and noveltyThis study provided information on retrogradation‐related changes in the properties of AS‐treated starch. Temperature‐cycled retrogradation can be used as a physical modification method to enhance the RS content of AS‐treated starch, allowing AS‐treated starch to be used as a low‐glycemic index ingredient.