Theoretical Rheology Analysis of Chocolate in A Rotating Tangential Process

ABSTRACT The chocolate is a complex fluid where its rheological parameters are highly dependent on the components and quality parameters, such as the particle size distribution and purity. In principle, the friction factor indicates several quality aspects of chocolate during the consumer experience. This study presents a theoretical approach for computing the friction factor for three types of chocolate for a commercial coating equipment similar to a concentric rotating process. The rheological data came from the literature and followed the Bingham, Herschel‐Bulkley, and Casson rheological models. The strategy solved the angular momentum equation by applying the fourth‐order Runge–Kutta method with a shooting approach; the numerical calculation of the friction factor relates the wall shear stress to the kinetic energy of the averaged angular velocity. The results revealed that the velocity profile is directly proportional to the temperature and inversely proportional to the outer angular velocity and the size of the displacement zone. The flow curves validated the results, where the Casson model reached a good representation of the experimental data from the literature. The friction factor values are inversely proportional to the cocoa composition and directly proportional to the content of non‐components of coca. Thus, the purity of chocolate contrasts with the prediction of the friction factor through this approach. Based on these results, this approach may be extended to other industrial equipment in order to relate the quality of chocolate and the flow behavior.