208 MILK AND DAIRY PRODUCTS PART 



Since about 1895 the manufacture of certain preparations 

 from the casein of milk has been commenced, and at the present 

 time large quantities are prepared both as additions to foods 

 and also for special use in cases of disease. For both these 

 purposes casein offers great advantages, for it is easily absorbed 

 by the organism without forming evil-smelling decomposition 

 products, as is the case with most other protein substances. 

 Further, protein can be bought more cheaply in the form of 

 casein than, for example, in eggs. 



In all the preparations which are to be found at the present 

 time in commerce, and have been prepared for the above- 

 mentioned purposes, the insoluble casein has been converted 

 into a soluble alkali compound. 1 



For the sake of comparison the chief properties of the most 

 important food preparations of casein will be found in tabular 

 form on the opposite page. 



Casein is now prepared in considerable quantities for purely 

 technical purposes by precipitating separated milk with com- 

 mercial hydrochloric or sulphuric acid, and then drying and 

 grinding the precipitated mass. In certain districts, e.g. the 

 Argentine, strongly acid whey is used for the precipitation. 

 When prepared in this way the casein is naturally insoluble in 

 water, and it finds considerable application in certain branches 

 of industry. In some cases advantage is taken of the property 

 which casein possesses of giving glue-like substances with 

 alkalies. Casein, after treatment with formaldehyde, yields a 

 substance which resembles in its properties gelatine or celluloid. 

 The first of these substances is used in considerable quantity 

 in dyeing and calico-printing, and the second for the preparation 

 of photographic films and for imitation tortoiseshell, ivory, 

 amber, horn, etc. 



The whey which remains after the precipitation of the casein 

 of milk by rennet serves for the preparation of milk sugar. 

 This sugar is almost exclusively used as an addition to mixtures 

 of cow's milk and water (cream being sometimes added) in the 

 feeding of infants. The addition of milk sugar in such cases 

 makes up the percentage of that substance in the food, for it 



1 A detailed account of a large number of such preparations are to be found 

 in Max Heim's Die kilnstlichen Ndhrprdparate und Anregungsmittel, Berlin, 

 1901, pp. 68-94 ; also in Die Mayermilch- Verwertuny in den Molkereren, by 

 C. Knoch, Leipzig, 1903, pp. 120-134. 



