Investigating the rheological properties of molten sugar‐free dark chocolates

Abstract This study examined the steady‐state and dynamic rheological properties of molten dark chocolate produced from sorbitol, isomalt, and inulin sugar substitutes at 40°C. All samples had a shear‐thinning and thixotropic behavior. Bulk sweeteners, according to their molecular structures, could be effective on the apparent viscosity as well as yield stress. Dynamic oscillatory measurements of the considered molten samples showed the liquid‐like behavior of inulin and isomalt, and the weak gel‐like behavior of sucrose and sorbitol. Sugar substitution decreased the G ′ and G ″ values of the samples. Among the samples, only those containing sorbitol within 50–100 rad/s range obeyed the Cox–Merz rule. The data related to the obtained compliance ( could be well fitted to the Kelvin model ( R 2 = 0.994) as a function of time. Compliance values ( were increased with the sugar substitution, thus showing that deformation and internal viscosity () were decreased with sugar substitution. According to the results of this study, sugar substitution remarkably influenced the structures of dark chocolate samples. For this reason, the use of bulk sweeteners mixture in the formulation can be recommended. Practical applications Over the past decennium, nutritive sweeteners are regarded as ingredients replacing the physical bulk as well as sweetness of sugar. Such products are also called “sugar replacers” or “bulk sweeteners.” Replacement of sucrose with bulking agents can lead to the reduction of calories, glycemic index, as well as preventing dental cavities. Therefore, it is necessary to make suitable products for people suffering from diabetes; accordingly, formulations have been developed using sugar replacers.