Some Structural and Thermodynamic Parameters of Maize Starch from Different Maize Genotypes

The morphology, thermodynamic, and physicochemical properties of maize starch isolated from different maize cultivars with different genotypes are analyzed. The considered maize starches represent four groups of starches: wx, ae, su, and mixed genotypes. All the starches are found to contain granules with oval and irregular shapes, their proportion differing for different genotypes. Starches from the su maize genotype have the smallest granules, compared to the wx and ae starches. An increase in the amylose content of wx and ae maize starches considered here results in the accumulation of defect structures in them, which is seen as a lowering of values for the thermodynamic parameters characterizing their melting. The thermodynamic parameters of dissociation of amylose-lipid complexes (i.e., the temperature and enthalpy) for ae and wx maize starches are inferior to those of the su genotype. All of the considered starch genotypes have similar thicknesses of their crystalline lamellae, practically independent of the amylose content. The dynamic viscosity of gels prepared using the starches decreases as their amylose content increases, irrespective of the genotype of plant they were isolated from.