Physicochemical and Structural Properties of Starches from Diverse Sweetpotato Genotypes Grown in Louisiana, United States

Abstract

Starches were extracted from 12 sweetpotato (Ipomoea batatas) genotypes, and their physicochemical and functional properties were evaluated. The starches were shown to have moisture contents of 5.4–9.9%, ash contents of 0.1–0.78%, and amylose contents from 11.9% to 26.13%. The water and oil absorption capacities ranged from 0.78 to 1.15 g/g and 0.57 to 0.72 g/g, respectively. The swelling power and solubility index varied from 9.44% to 13.5% and 4.63% to 12.4%, respectively. All samples exhibited A-type crystallinity, with relative crystallinity from 25.2% to 31.0%. Granules were smooth and round to polygonal in shape, with average sizes from 12.1 to 16.3 μm. Gelatinization temperatures ranged from 55.6 to 85.0 °C, and enthalpy varied from 8.33 to 62.7 J/g. Rheological tests of starch-water mixture at a concentration of 0.5% indicated typical non-Newtonian fluid behavior with shear-thinning properties, and dominant elastic moduli. These results highlight the variability and potential of sweetpotato starches for food, pharmaceutical, and industrial applications.