Modeling grinding kinetics of fat based anhydrous pastes

The objective of this research was to study the kinetics of grinding of an anhydrous paste based on hazelnut and cocoa, in stirred ball mills by means of particles size determination and rheological analysis. Grinding was carried out in a pilot refiner (30 °C, 72 rpm, 60 kg of 11-mm diameter stainless steel balls) with 10 kg of paste. The grinding kinetics was described in terms of the cumulative oversize fraction by the second order solution of the population balance model allowing the estimation of the first and the second Kapur constants as a function of particle size class. The flow curves of refined pastes were successfully modeled with the Casson rheological model and can be explained by the theory of dense suspensions. Further studies are however necessary to develop a model for the description of the rheological behavior as a function of solid packing fraction and shear rate. •A population balance approach proved adequate to model grinding kinetics.•The first and second Kapur constants were estimated and regressed on size class.•Casson model describes the pseudoplastic behavior of the refining paste.•The packing fraction of the refining paste was related to its rheological behavior.•Grinding affected mainly the rheology of the pastes.