Powdered milk is a soluble powder obtained by drying normalized pasteurized cow's milk. It is usually diluted in warm water and consumed as a drink, while retaining many of the beneficial properties of fresh pasteurized milk. Has wide application in cookery. Included in many types of infant milk formulas.
The production of powdered milk is due to the longer shelf life of this product compared to regular milk. There is also instant milk powder.
Cow's milk is standardized, pasteurized and thickened. Then the condensed milk is homogenized and dried on spray or roller dryers.
On spray installations, milk is dried at a temperature of 150-180 ° C.
Spray dryers are more popular with manufacturers due to their high performance and consistent quality of milk powder.
Initially, roller dryers based on the conductive drying method were predominantly used for milk drying. Typically, the roller dryer receives whole milk concentrate after multi-cyclone evaporators with a solids content of about 40%. The finished product has a residual moisture content of about 3%.
Powdered milk produced on roller dryers has special organoleptic properties. When condensed milk comes into contact with the heated surface of the drum, it caramelizes. Thus, milk dried on roller dryers has a peculiar taste of caramel. Roll-dried milk powder has a large amount of free fats, therefore it is an indispensable ingredient in the chocolate industry, which can significantly reduce the amount of expensive cocoa butter. A significant disadvantage of this type of drying is low productivity: depending on the size of the roller installation, up to 1000 kg/h.
After drying, the milk is sifted and cooled.
The shelf life of whole milk powder is less than skimmed milk, as fats are prone to spoilage - rancidity. It should be stored at t from 0 to 10 °C and relative air humidity not higher than 85% for up to 8 months from the date of production.
Instant milk powder is obtained by mixing whole and skimmed milk powder. The mixture is moistened with steam, after which it sticks together into lumps, which are then dried again.
Whole milk powder is used mainly for the nutrition of the population, and skim milk is used for the manufacture of confectionery and animal nutrition. The use of whole milk powder in a number of countries is limited due to the high content of oxysterols formed during thermal drying.
It is widely used in the manufacture of bakery products and meat products (as a binder).
Milk that has been obtained by diluting powdered milk with water is called reconstituted milk.
At the end of the XIX century. industrial production began.