wrapping of milk powder is a combination of fourpaper layers, one bitumen paper layer and one layerof polyethylene foil. Metal barrels lined with poly-ethylene bags, or cans covered with aluminum foilare also used for packing powders. When theproduct, especially whole milk powder, needs to bestored for a long period, the packing is carried out inan atmosphere of inert gas, or under a partial vacuumof 4.05.3 kPa in order to avoid oxidative changes offat and other milk components. When planning thequantity of wrapping material, it is necessary to takebulk density into account, as it is markedly affectedby processing parameters and techniques. All milkpowders are stored at ambient temperature, ifproperly produced and packed.

Applications

Milk powder is a very valuable nutritious foodmaterial. It can be used in powder form in variousdry food or beverage blends, as well as in recon-stituted form. The greatest proportion of milkpowder is still used in confectionery: chocolate, cara-mels, soft sweets, coatings, biscuits and cakes. Inthese products, milk powder not only has a nutritiveeffect but also improves consistency, taste or avourof confectionery products.

Milk powders are also used in the dairy industry asan ingredient in products such as ice cream blends orprocessed cheeses. The whole dairy industry incountries without their own milk production isbased on milk powder, which is reconstituted andprocessed. Milk powder is used as a supplement inother specic food industries, such as coatings,creams, sauces, soups, ready-made dishes, breakfastblends, food blends for special categories (nutritionblends for geriatrics, athletes, convalescents), blendsfor meal replacement, modied milk products andimitation milk products.

Analysis

The quality of milk powders is markedly determinedby the total heat treatment of the operations duringprocessing and the techniques of particular opera-tions, such as concentrating or drying. In addition,the storage time and temperature regime affect thequality characteristics of the powders.

The structure and physical properties of milkpowders are most severely affected by the dryingtechnique and parameters. Low bulk density is adisadvantage to milk powder quality. However,there are modern spraying methods (e.g. using asteam swept wheel) that increase the bulk density.The rate of dissolving is one of the most important

characteristics. For these and other physical char-acteristics (see Milk Powders: Physical and Func-tional Properties of Milk Powders).

Chemical analysis of milk powders includescontrol of moisture, total fat, free fat, oxidativechanges, hydrolytic changes and the intensity of theMaillard reaction. Microbiological and sensoryanalysis of milk powders should be carried out also,in order to conrm the high quality of the powder.

See also: Dairy Ingredients in Non-dairy Foods.Drying of Milk: Drying Principles. Maillard Reactions.Milk Powders: Physical and Functional Properties ofMilk Powders.

Further Reading

Bylund G (1995) Dairy Processing Handbook. Lund: TetraPak Processing Systems AB.

Caric M (1993) Concentrated and dried dairy products. In:Hui YH (ed.) Dairy Science and Technology Handbook,vol. 2, Product Manufacturing, pp. 257300. NewYork: VCH.

Caric M (1994) Concentrated and Dried Dairy Products.New York: VCH.

Hall CW and Hedrick TI (1975) Drying of Milk and MilkProducts. Wesport: AVI.

Knipschildt M (1986) Drying of milk and milk products.In: Robinson RK (ed.) Modern Dairy Technology, vol.1, pp. 131234. London: Elsevier.

Masters K (1985) Spray-Drying Handbook, 4th edn.London: George Godwin.

Masters K (1985) Spray-drying. In: Hansen R (ed.)Evaporation, Membrane Filtration and Spray Drying,pp. 299345. Vanlose: North European Dairy Journal.

Pisecky J (1997) Handbook of Milk Powder Manufacture.Copenhagen: Niro A/S.

Physical and FunctionalProperties of Milk PowdersM Caric and S Milanovic , University of Novi Sad,Novi Sad, Yugoslavia

Copyright 2002, Elsevier Science Ltd. All Rights Reserved

Introduction

The properties of milk powders are categorized asphysical, functional, biochemical, microbiologicaland sensory. There is a signicant interrelationshipamong them, which affects the nal quality of the dryproduct.

1874 MILK POWDERS/Physical and Functional Properties of Milk Powders