MANUFACTURE OF CASEIN. 



25 



only handled as easily as that precipitated with sulphuric acid but is 

 not nearly so tough nor so hard to grind. 



COMPARISON OF THE DIFFERENT METHODS OF MAKING SKIM-MILK CASEIN. 



The quality of casein made by the ejector method is superior in 

 many ways to that made with the acid and cooked-curd methods. 

 It shows better strength, dissolves more readily, and retains a fluid, 

 viscous body at room temperature, giving it better working prop- 

 erties. When dissolving acid and cooked-curd casein, complete solu- 

 tion is retarded by the formation of a heavy, short, viscous body, 

 which upon cooling has a decided tendency to congeal and lose its 

 fluidity, more especially the cooked-curd casein, making it very 

 difficult to mix well with other solutions in the cold. Table 4 shows 

 the comparative strength of casein made from the same lots of skim 

 milk with the ejector, acid, and cooked-curd methods. 



Table 4. — Comparative strength of skim-milk casein made with ejector, acid, 

 and cooked-curd methods. 



Skim milk. 



Times 



curd 



washed. 



Acidity 

 of drain 

 water. 



Drying 

 temper- 

 ature. 



Method. 



Casein 

 required. 



Lot No. 



Portion 

 No. 



56.25 

 56.25 

 56.33 

 56.33 

 56.34 

 56.34 

 56.59 

 56.59 

 56.59 

 56.60 

 56.60 

 56.60 

 56.61 

 56.61 

 56.61 

 56.89 

 56.89 

 56.89 

 56.90 

 56.90 

 56.90 



25A 

 25B 

 33A 



33 B 

 34A 



34 B 

 59A 

 59B 

 59C 

 60A 

 60B 

 60C 

 61A 



. 61C 

 61 D 

 89A 

 89B 

 89C 

 90A 

 90B 

 90C 



1 



4 

 1 

 4 

 1 

 4 

 

 

 3 

 

 

 3 

 

 

 3 

 1 

 1 

 3 

 3 

 1 

 3 



Per cent. 

 0.38 

 .10 

 .22 

 .00 

 .14 

 .02 



° F. 

 130 

 130 

 130 

 130 

 130 

 130 

 130 

 130 

 130 

 128 

 128 1 

 128 

 130 

 130 

 130 

 124 

 124 

 124 

 124 

 124 

 124 



Sulphuric acid. 



Ejector 



Sulphuric acid. 



Ejector 



Sulphuric acid. 



Ejector 



Sulphuric acid. 

 Cooked curd . . 



Ejector 



Cooked curd. . 

 Sulphuric acid. 



Ejector 



Sulphuric acid. 

 Cooked curd. . 



Ejector 



Sulphuric acid. 

 Cooked curd. . 



Ejector 



Sulphuric acid. 

 Cooked curd.. 

 Ejector 



Grams. 

 9 



8+ 

 9 

 8 

 8 

 8 

 10 

 9+ 

 8 

 9 

 9 

 8 

 9 



9+ 

 8 

 8 

 9 



7+ 

 S 

 9 

 7+ 





.01 

 .28 





.53 

 .25 

 .06 

 .13 

 .10 

 .09 

 .04 

 .06 





In seven out of eight experiments the wax test showed the ejector- 

 method casein to be the strongest, while in one lot no difference was 

 noticeable. While the difference in strength is not marked in all 

 cases, it shows up with such consistency as to warrant fully the con- 

 clusion that the ejector casein is stronger when made under proper 

 conditions. The increased strength of the ejector-method skim-milk 

 casein and its much better working properties make it the most 

 desirable from the standpoint of quality. The ejector method requires 

 more vat capacitj^, as the skim milk has to be held until it has 

 developed a sufficient degree of acidity to bring about a firm coagu- 



