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The thermal and retrogradation properties of oat starches from two cultivars (NO 753‐2 and AC Stewart) were characterized in the presence of glucose, fructose and sucrose at a concentration of 36% w/v. In both oat starches, amylose leaching (AML) and swelling factor (SF) decreased in the presence of sugars (sucrose > glucose > fructose). These decreases were more pronounced in AC Stewart starch. The decrease in AML showed that sugars interact with amylose chains within the amorphous regions of the starch granule. The gelatinization transition temperature and the enthalpy of gelatinization increased in the presence of sugars (sucrose > glucose > fructose). The above increase was also more pronounced in AC Stewart starch. The decrease in SF and the increase in gelatinization parameters indicated that these changes were influenced by the interplay of factors such as starch‐sugar interaction, changes in water structure in the presence of sugars, and the antiplastizing properties of sugars relative to water. The retrogradation enthalpy and the X‐ray diffraction intensities of NO 753‐2 and AC Stewart starch gels (stored at 4C) increased in the presence of sugars (glucose > fructose > sucrose). These changes were more pronounced in NO 753‐2 starch. The results showed that interaction (during storage) between leached amylopectin and sugar molecules was the main causative factor influencing oat starch retrogradation.

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Fat substitutes are becoming an important part of the North American diet. Many Americans are looking for ways to enjoy their favorite foods while maintaining a low‐calorie diet. Food scientists are developing new food constituents that will mimic the function of fats in foods while keeping the calorie contents of foods low. Dietary fat substitutes are food components able to replace, completely or partially, dietary fat in such a manner that certain physical and organoleptic properties of the food product involved are left unaltered as much as possible. There are two principal approaches to the replacement of dietary fat. The first involves hydratable carbohydrates and proteins with the mouthfeel of fats. The second includes nonabsorbable synthetic substances with the physical properties and technical function of fat within foods.