166 



NEUTRALIZATION OF SOUR CREAM 



standpoint of neutralization of cream, it may be considered 

 equivalent to free casein. 



When lime is added to the sour cream the concentration 

 of the acid is very greatly reduced and the concentration of 

 the calcium is increased to excess. In the presence of free 

 casein, these conditions are most favorable to the formation 

 of calcium caseinate. 



Since both the lime, in the form of milk of lime, and the casein 

 are in a similar physical state and have a specific chemical at- 

 traction for each other, it appears unnecessary for the calcium 

 to go into solution in order to react on the casein. 



That such action takes place is indicated by the fact that 

 when cream is poured over dry hydrated lime, the lime gradually 

 becomes coated with a layer of casein-like material that adheres 

 to the particles of lime with which it comes in immediate contact. 

 This is especially noticeable on heating. A similar action seems 

 to take place when the lime is added to the cream in the vat, 

 in concentrated form, either due to inadequate dilution of the 

 lime mix or lack of proper distribution. Large lumps and masses 

 form, the solid constituents of which consist largely of curd, with 

 a very high lime content, and in which is locked up a good deal 

 of fat, as shown in Table 28. 



Table 28. Composition of Lumps in Cream Caused by the Use 



of Too Coarse or Too Concentrated Lime, or By Incomplete 



Distribution of the Lime Mix. 



The greater affinity of the lime for the casein than for the 

 lactic acid in the cream is proven by analysis of the serum and 

 the curd, respectively, of cream that was neutralized to .26% 

 acid with milk of lime of the standard strength of two pounds 

 of dry hydrated lime made up with water to one gallon of mix, 

 as shown in Table 29. 



