VISCOSITY OF MOLTEN MILK CHOCOLATE WITH LACTOSE FROM SPRAY-DRIED WHOLE-MILK POWDERS

Dry whole-milk powders containing 0, 30, 50 and 70% nominal lactose pr epared by spray-drying alone, or followed by post-drying crystallizati on, were incorporated into milk chocolate to give 0-50% substitution o f lactose for sucrose. Increasing the concentration of amorphous lacto se from spray-dried powders in the chocolates decreased viscosity, inc reased particle size of refined chocolate mass, and lowered the concen tration of surface-active agents at which a minimum in Casson yield va lue was observed. Increasing the concentration of crystalline lactose from milk powders in the chocolates increased viscosity, decreased par ticle size, and increased the concentration of surface-active agents a t which a minimum in Casson yield value was observed. Conditions which affect lactose crystallinity in milk powders, such as improper storag e and handling prior to use in chocolate production, could be responsi ble for variations in chocolate viscosity noted sometimes by processor s.