Milk powder manufacture

Pisecky, J. 1997. Handbook of Milk Powder Manufacture. Niro A/S, Copenhagen. 

Mutarotation has limited, rather diagnostic, significance in food chemistry and technology. Practical use of this reaction is demonstrated in milk powder manufacture. Evaporation of milk at a rate lower than mutarotation of lactose yields a product with less a-lactose isomer, which crystallizes in prism- or pyramid-like form. Fast milk evaporation gives an amorphous mixture of a- and [3-lactose (5.7b). 

Of all the major unit processes in conventional milk powder manufacture such as preheating, concentration, and drying, the preheating step has the major effect on milk powder functionality. In fact, skim milk powders are still classified on the basis of the heat treatment applied to the milk during powder manufacture (American Dairy Products Institute,... 

FIGURE 39,7 Spray-drying process scheme (one stage). Hot air drying/drops cocurrent = ao high T for dry product. Residence time 10 s, continuous process). (Adapted from Pisecky, J., Handbook of Milk Powder Manufacture, Niro A/S/, Copenhagen, Denmark, 1997, 261p.)... 

Oldfield, D.J. Taylor, M.W. Singh, H. Effect of preheating and other process parameters on whey proteins reactions during skim milk powder manufacture. International Dairy Journal, 2005, 75,501-511. 

Pasteurisation of milk does not significantly affect the vitamin content. In the case of UHT milk, the vitamin loss is about 5% of the original level and the loss after 6 weeks of storage of UHT milk is 20-35%. The natural vitamin content in fermented dairy products is affected only slightly by fermentation. Milk powder manufacture and storage of milk powder result in small losses of the vitamin. 

The CAP has succeeded in reducing the amount of milk powder used in bakery products in Europe. The high price of skimmed milk encouraged manufacturers to look for substitutes and in some cases reduce levels of use that had started when milk powder was much cheaper. 

Milk solids are normally used as either milk powder or sweetened condensed milk in food manufacturing. Skim milk solids are an essential part of toffees as well as contributing useful colour and Maillard reaction flavours to baked goods. 

Evaporated milk is a more modern product than sweetened condensed milk. It is not normally used in food manufacture. This material has no technical or economic advantages over milk powder. 

While liquid milk is little used in biscuit manufacture for practical reasons to do with lack of stability, skimmed milk solids are used. The preferred ingredient is skimmed milk powder. This is normally dispersed in twice its own weight of water to ensure that it is evenly dispersed in the finished product. The reconstituted milk powder has the same keeping properties as liquid milk so it must be refrigerated. Merely dry blending the milk powder is likely to produce a finished product with small brown specks of caramelised milk powder in it. 

Case reports of occupational asthma include a candy worker exposed to lactalbumin (Bemaola et al, 1994) and a bakery worker exposed to milk powder (Toskala et al, 2004), a candy worker and a jam-manufacturing worker exposed to pectin (Cohen et al, 1993 Kraut et al, 1992), a worker in... 

Although rancidity is a serious defect in market milk, it has also been utilized profitably. Whole milk powder made from lipase-modified milk has generally been accepted by chocolate manufacturers. It is used as a partial replacement for whole milk because it imparts a rich, distinctive flavor to milk chocolate, other chocolate products like fudge, and compound coatings, caramels, toffees, and butter creams (Ziemba 1969). 

F. Guyomarc h, F. Warin, D. D. Muir, and J. Leaver, Lactosylation of milk proteins during manufacture and storage of skim milk powders, Int. Dairy J., 2000, 10, 863-872. 

While free fat remains a controversial concept in liquid dairy products, it undoubtedly has an important role in whole milk powder (WMP) for certain applications (e.g., chocolate manufacture) high-free fat WMP is favored. Keogh et al, (2003) reported that the particle size in chocolate mixes after refining and the viscosity of the molten chocolate decreases as the free fat content of the WMP increased such changes have significant implications for the mouthfeel and smoothness of chocolate. For more information on the role of fat in milk powder, see Chapter 13... 

Tamime, A.Y., Kalab, M., Davies, G., Younis, M.F. 1990. Microstructure and firmness of processed cheese manufactured from Cheddar cheese and skim milk powder cheese base. Food Struct. 9, 23-37. 

Each step in the processing and packaging of dry milk products can influence the properties of the finished product. The total heat treatment (i.e., time x temperature) for each step during the manufacture of milk powder is important in determining its properties. The method of heating and the total heat exposure influence protein denaturation, oxidation of the fat and the subsequent shelf-life of the powder. 

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