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

The influence of both formulation and processing variables on the phys. characteristics of milk chocolate has been studied during milling with a pilot ball mill. Nine exptl. 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 addn. 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 expts., the solid particle size was effectively reduced during the first 120 min of refining; after this time the particle size redn. assumed an asymptotic trend. The addn. of lecithin at the beginning of the refining kept the viscosity low and const. throughout the process, thus allowing the addn. of milk from the start of the process, regardless of the technol. adopted for milk drying.