Influence of ethylcellulose-Medium chain triglycerides blend on the flow behavior and β-V polymorph retention of dark chocolate

Abstract

Chocolate manufacturing involves steps during which molten mass is prepared to be converted in a solid with selected textural and melting properties which are vital for the consumer's acceptance. A central element in this behavior is the continuous oily phase (cocoa butter), in which solid particles like sucrose and cocoa solids, refined to a selected particle size are dispersed and stabilized. Emulsifiers are important in particle coating and modify the viscosity of chocolate mass to give it adequate flowability during manufacturing. Furthermore, these molecules should not hinder the appearing of β-V polymorph during chocolate solidification. In this work we evaluated ethylcellulose (EC) copolymers with different mean molecular weights (MMW) dissolved in medium chain triglycerides (MCT) oil, on the rheological and crystallization parameters of molten chocolate and cocoa butter. Rheology shows that EC induced a dose-dependent increase in yield value and viscosity, whereas MCT mainly induced a reduction in yield value. Therefore, by adjusting the EC concentration in the mixture it was possible to tune the rheological parameters of molten chocolate. Besides, X-ray diffraction showed that at the low proportions used to modify the rheological parameters (up to 0.2% EC and 1.9% TCM) EC-MCT blend did not affect the crystallization of cocoa butter which retained the β-V polymorph. The effects observed did not show a direct dependence with the MMW of EC suggesting that the modification of the rheological parameters is mostly thermodynamic (due to its surface activity) rather than kinetic (due to an increase in viscosity).