The effects of sugars and sugar alcohols on the pasting and granular swelling of wheat starch

Abstract

Replacing added sugars with low-glycemic, natural, and/or low-calorie sweeteners in baked goods without altering texture or quality traits is challenging. Starch thermal properties (gelatinization, pasting/swelling, retrogradation) determine the final set structure of baked goods and are altered by many variables, including sweetener type and concentration. This study investigated how different sugars and sugar alcohols known to alter starch gelatinization temperatures also affected the pasting behavior and granule swelling of wheat starch. Wheat starch slurries (10% w/v) with increasing concentrations (0–4.0 M and saturated) of sugars and sugar alcohols (glucose, fructose, sorbitol, maltose, isomaltulose, isomalt, and sucrose) were studied. Rapid Visco Analyser (RVA) profiles were generated to observe sweetener effects on starch pasting behavior. Granule particle size measurements were taken at various timepoints during RVA analysis to document sweetener effects on granular swelling. Sweetener type and concentration significantly affected starch pasting and granule swelling. Generally, disaccharides increased starch pasting temperatures more than monosaccharides, while monosaccharides increased peak and final viscosities of starch solutions more than other sweeteners at the same concentrations. Isomers had different effects on starch pasting temperatures and paste properties, as did sugar alcohols compared to their unreduced sugar counterparts. Indicators of intermolecular hydrogen bond capability of sweeteners strongly correlated to many starch pasting properties. Sorbitol, isomaltulose, and isomalt had the most similar effects on starch pasting properties compared to sucrose, on a percent solids basis, and could be useful starting points for reformulation efforts in reduced-sugar products for which control of starch pasting behavior is important.