Starches were isolated from the maize (Zea mays) inbred line Oh43, from its single mutants (amylose extender [ae], brittle-1 [bt1], brittle-2 [bt1], dull-1 [dul], floury-2 [fl2], horny [h], shrunken-2 [sh2], sugary- 1 [sul], and waxy [wx]), and from the double-mutant combinations within Oh43. Differential scanning calorimetry was used to determine the onset temperature (To), range, and enthalpy (DeltaH) of gelatinization and retrogradation, and percentage of retrogradation. The gel strength was measured by using a Voland-Stevens texture analyzer. For gelatinization, the starches of wx dul and sh2 dul had the highest To. Double-mutants ae bt2 and ae dul had the highest To of retrogradation. The highest DeltaH of gelatinization was observed for h wx. The gelatinization enthalpy peak for bt1 starch had a characteristic low temperature shoulder and wide range. Compared with the respective single mutants, most double-mutant combinations had higher To and DeltaH for gelatiniztion and lower To for retrogradation. For gel strength, the dul starch gave the lowest values for firmness and stickiness among the samples. Double mutants generally had gel strength measurements lower than those of the single mutants bt1, bt2, fl2, h, and sh2 but higher than those of dul.
Available at: http://works.bepress.com/pamela_white/51/