Characterization of starch structures and properties of maize mutants from the Oh43 inbred line

Abstract

Starches were isolated from the maize (Zea may L.) inbred line, Oh43, and its single mutants [amylose extender (ae), brittle-1 (btl), brittle-2 (bt2), dull-1 (dul), floury-2 (fl2), homy (h), shrunken-2 (sh2), sugary-1 (sul), and waxy (wz)]. and the double-mutant combinations within Oh43. Differential scanning calorimetry (DSC) was used to determine the onset temperature (TQ), range, enthalpy (AH) of gelatinization and retrogradation, and percentage of retrogradation (r%). The gel strength was measured by using a Voland-Stevens texture analyzer. For gelatinization, the starches of wj: dul and sh2 dul had the highest TQ. Double-mutants ae bt2 and bt2 dul had the highest Tp of retrogradation. The highest AH of gelatinization was observed for h wx. The gelatinization enthalpy peak for btl starch had a characteristic low temperature shoulder and wide range. Compared with the respective single mutants, most double-mutant combinations had higher TQ and AH for gelatinization and lower TQ for retrogradation. For gel strength, the dul starch gave the lowest values for Hrmness and stickiness among the samples. Double mutants generally had gel strength measurements lower than those of the single mutants btl, bt2,fl2, h, and sh2, but higher than those of dul.