Effects of Sugars and Sugar Alcohols on the Gelatinization Temperatures of Wheat, Potato, and Corn Starches.

The gelatinization temperature (T-gel) of starch increases in the presence of sweeteners due to sweetener-starch intermolecular interactions in the amorphous regions of starch. Different starch botanical sources contain different starch architectures, which may alter sweetener-starch interactions and the effects of sweeteners on T(gel)s. To document these effects, the T(gel)s of wheat, potato, waxy corn, dent corn, and 50% and 70% high amylose corn starches were determined in the presence of eleven different sweeteners and varying sweetener concentrations. T(gel)s of 2:1 sweetener solution:starch slurries were measured using differential scanning calorimetry. The extent of T(gel)elevation was affected by both starch and sweetener type. T(gel)s of wheat and dent corn starches increased the most, while T(gel)s of high amylose corn starches were the least affected. Fructose increased T(gel)s the least, and isomalt and isomaltulose increased T(gel)s the most. Overall, starch T(gel)s increased more with increasing sweetener concentration, molar volume, molecular weight, and number of equatorial and exocyclic hydroxyl groups. Starches containing more short amylopectin chains, fewer amylopectin chains that span through multiple clusters, higher number of building blocks per cluster, and shorter inter-block chain lengths exhibited the largest T(gel)increases in sweetener solutions, attributed to less stable crystalline regions.