Influence of formulation and processing variables on ball mill refining of milk chocolate

The influence of both formulation and processing variables on the physical characteristics of milk chocolate has been studied during milling with a pilot ball mill. Nine experimental millings were carried out varying the type of dried milk used (roller, high free fat and spray-dried milk) and the time of lecithin and dried milk addition during the refining process. For the samples collected during 2 h of milling, particle size, moisture, Casson plastic viscosity and yield value were evaluated. In all the experiments, the solid particle size was effectively reduced during the first 120 min of refining; after this time the particle size reduction assumed an asymptotic trend. The addition of lecithin at the beginning of the refining kept the viscosity low and constant throughout the process, thus allowing the addition of milk from the start of the process, regardless of the technology adopted for milk drying.