Thermal behavior of maize starches with different amylose/amylopectin ratio studied by DSC analysis

The main gelatinization parameters of starches from three maize varieties with wide variation in amylose content (53, 30, and 20%) were obtained using DSC analysis. All starches were characterized by high lipid levels. Gelatinization temperature decreased with increasing amylose content both for native and treated (defatted and annealed) starches. For all studied starches irrespective of amylose content, A-type crystalline packing in semi-crystalline starch granules was observed as judged by the characteristic shift of starch melting temperature in 1 M KCl. Observed shifts of amylopectin melting temperatures to higher values in defatted starches were ascribed to the elution of lipids and/or lipid-containing complexes from crystalline lamellae. Two types of amylose-lipid complexes with different thermostability were detected in aqueous starch gels with concentration equal/more than 10%. It was suggested that the high level of lipids strongly contributed to the gelatinization properties of studied starches.