Functional properties of starch from normal and mutant corn genotypes

The thermal and functional properties of starches from a wild-type corn, and amylose extender25, dull39, sugary2 (su2), and sugary1(su1) corn mutants, all in the same (ExSeed68) genetic background were evaluated and related to their structural features obtained in a previous study. The onset temperature of gelatinization values of starches from all mutant lines ranged from 52.0 to 62.9 °C, temperatures that were all lower than that of the wild-type starch. The viscosity of the su2 starch was relatively stable over the cooking process, showing only a small breakdown of the peak viscosity, suggesting high stability of starch granules against mechanical shear. The su1 mutant starch formed the strongest gel among all starch-gel samples during measurements of both fresh and stored gel. Correlations were established between amylose percentage, chain-length distributions and pasting properties; Rapid Visco Analyser (RVA) and Differential Scanning Calorimeter (DSC) parameters; and DSC and texture analysis data.