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 prepared by spray‐drying alone, or followed by post‐drying crystallization, were incorporated into milk chocolate to give 0–50% substitution of lactose for sucrose. Increasing the concentration of amorphous lactose from spray‐dried powders in the chocolates decreased viscosity, increased particle size of refined chocolate mass, and lowered the concentration of surface‐active agents at which a minimum in Casson yield value was observed. Increasing the concentration of crystalline lactose from milk powders in the chocolates increased viscosity, decreased particle size, and increased the concentration of surface‐active agents at which a minimum in Casson yield value was observed. Conditions which affect lactose crystallinity in milk powders, such as improper storage and handling prior to use in chocolate production, could be responsible for variations in chocolate viscosity noted sometimes by processors.