Effect of Different Bulk Sweeteners on the Dynamic Oscillatory and Shear Rheology of Chocolate

Abstract

Effect of different bulk sweeteners including maltitol, isomalt and inulin on the steady and dynamic rheological behaviors as well as chocolate structure was investigated. All the chocolate samples showed shear-thinning behavior, which was mainly affected by the shear rates. Among different rheological models, the power law model was the suitable one (high R2) for the chocolate samples containing bulk sweeteners. As the bulk sweetener has the more solid volume fraction, the more flow behavior index n was obtained. Bulk sweeteners depending on their molecular structures were influenced on the apparent viscosity and yield stress. The mechanical spectra of chocolate showed the liquid-like behavior of inulin and maltitol and solid- like behavior of sucrose and isomalt. It was also revealed that the chocolate network structure was completely influenced by temperature and related to the frequency range. During thermal processing, the bulk sweeteners did not have any effect on the chocolate consistency and they cause to reduce the network strength of the chocolate. In addition, the critical stress was sensitive to the type of bulk-sweeteners in the chocolate. Consequently, chocolate can be considered as a weak dispersion which makes aggregates and can be modeled by the weak physical gel model. Current research realized great insight to the chocolate rheology in different processes such as enrobing, shell formation and molding.

Keywords

• chocolate
• bulk-sweetener
• yield stress
• oscillatory rheology
• flow behavior