Oligosaccharides elevate the gelatinization temperature of wheat starch more than sucrose, paving the way for their use in reduced sugar starch-based formulations

The gelatinization of wheat starch influences the final structure and texture of baked goods. Sucrose effectively elevates the gelatinization temperature (Tgel) of starch more than many sweeteners, and maintaining a higher Tgel has been a challenge while reducing the amount of sucrose in baked goods. The objective of this study was to quantify the effects of 14 different oligosaccharides (OS: maltose, isomaltulose, kestose, maltotriose, melezitose, raffinose, stachyose, a fructo-OS, a galacto-OS, an isomalto-OS, lactosucrose, a xylo-OS, and two glucose-based dextrins), allulose, and sucrose at different concentrations (0 to 60% w/w) on the Tgel of wheat starch using DSC, and to determine which OS physicochemical properties best explained the Tgel results. OS type and concentration significantly altered Tgel. Many OS elevated the Tgel as much as or more than sucrose at the same solution concentrations, while allulose did not. The onset Tgel in water was 60 °C, in 60% sucrose was 96 °C, in 60% allulose was 80 °C, and Tgel increased up to 107-108 °C in 60% fructo-OS and Nutriose® solutions. The effects of OS on Tgel correlated most strongly (r > 0.95) with two OS solution parameters: the solvent effective volume fraction (ϕw,eff, related to solute intermolecular hydrogen bond density) and solution viscosity, to a lesser extent with solution water activity, and not to the glass transition temperature of the OS. Based on Tgel elevation, many of the OS are promising sucrose replacements in baked goods, which could facilitate their use in desirable higher fiber, reduced sugar starch-based baked product formulations.