316 COMPOSITION AND PROPERTIES OF MILK POWDERS 



Effect of Process of Manufacture. The influence of the 

 process of manufacture on the composition of the milk powder 

 refers primarily to modifications of the milk prior to desiccation, 

 although the method of desiccation itself also exerts a limited 

 effect. 



The greater the percentage of butterfat to which the original 

 milk has been standardized or modified, the lower must necessa- 

 rily be the percentage of solids not fat, and this same fact is true 

 also of the finished powder. Hence the milk powders may vary 

 from say one per cent of fat and possibly over 95 per cent of 

 solids not fat in the case of skim milk powder, to over 70 per cent 

 of fat and less than 30 per cent of solids not fat in the case of 

 cream powder. Whole milk powders generally contain from about 

 26 to 29 per cent fat. 



The degree of dryness, or per cent of moisture, aside from 

 atmospheric conditions is largely governed by the process of desic- 

 cation. Generally speaking, milk powders manufactured by the 

 spray-drying process contain less moisture than those made by the 

 film-drying and dough-drying processes. 



The spray-drying process, at its present state of perfection, 

 makes possible the removal of all but a very small percentage of 

 moisture. Spray powders containing as low as one per cent 

 moisture are quite possible ; in fact, the moisture content of these 

 powders, as found in commerce, ranges from about .5 per cent to 

 3.5 per cent, averaging about 1.5 to 2.5 per cent. 



The powders resulting from the. film-drying processes generally 

 contain from about 3 to 6 per cent moisture. 



Some milk powders, especially certain brands of foreign man- 

 ufacture, and particularly those of the dough-drying process, also 

 contain added sucrose. 



