172 NEUTRALIZATION OF SOUR CREAM 



of the lime and making the alkalinity of the portion of the lime, 

 so fixed, unavailable for acid reduction. 



Summary of Action of Lime in Sour Cream. Summing up 

 the foregoing discussion concerning the action of lime hydrate 

 when used as a neutralizer in sour cream, the following points 

 are of importance: 



(1) When a sufficient amount of lime is added to sour cream 

 to theoretically reduce the acidity in the cream to .25% acid, 

 the lime fails to accomplish the full extent of this acid reduction. 

 About 16 to 20% of the lime does not react. 



(2) This delinquency may be corrected by using approxi- 

 mately 20%i more lime hydrate, thus making the lime mix about 

 16% stronger than required theoretically, or by using instead 

 of calcium lime, magnesium lime. Magnesium lime containing 

 from 35 to 50%> magnesium oxide has an alkalinity equivalent in 

 strength to approximately 116 to 120% of pure calcium lime. 



(3) Lime has a marked affinity for casein. The absorption 

 of lime By the casein and the reduction of the casein acid are 

 greater than the absorption of lime by the serum and the reduc- 

 tion of the lactic acid. 



(4) When neutralization is carried to the neutral point, the 

 distribution of the neutralizing action in the components of cream 

 the serum, curd and fat is similar with sodium hydrate as it 

 is with lime water. 



(5) The acid test of the cream determines the total acidity 

 of the cream, including both the casein acid and the lactic acid, 

 It yields, therefore, the correct per cent of acid. 



(6) The deficiency of the neutralizing action of the lime is 

 due to physical and mechanical combination between portions 

 of insoluble lime and the curd. The fact that from 16 to 20% 

 of the lime does not react in the cream must be attributed to the, 

 great affinity of the lime for casein, particles of lime adhering 

 and becoming permanently attached to particles of free casein. 

 In this condition the lime so held is unable to exert its full neu- 

 tralizing action. 



Adding Lime Mix in Proper Manner. It is not enough to 

 use the right strength and amount of lime. The lime mix must 



