DETECTIOlSr OF LIME USED IN DAIRY PRODUCTS. 



21 



All the butters, the analyses of which are given in Table 15, were 

 alkaline to litmus to a greater or less degree, and had a peculiar foam 

 test and a sweetish smell on heating, especially those of high lime 

 content. When heated with dilute sulphuric acid all of them gave a 

 more or less distinct smell of butyric acid, thus indicating the pres- 

 ence of calcium butyrate. The water extracts of these butters were 

 alkaline to litmus paper and those containing the larger quantities of 

 calcium oxid were alkaline to phenolphthalein. Some of these sam- 

 ples have been kept for months in an ice-box without developing the 

 characteristic smell of rancid butter, although many became moldy 

 and possessed a bad odor. When the butter was treated with hot 

 alcohol, as in the determination of acids in fats, considerable acidity 

 was usually found, indicating the presence of free oleic and palmitic 

 acids. 



The liming of cream is a renovation of a deteriorated intermediate 

 product, while the liming of butter is a renovation of a more or less 

 spoiled final product. The chemistry of the two processes is differ- 

 ent. The main acid constituent of sour cream is lactic acid, and when 

 lime is added calcium lactate is probably the principal substance 

 formed, but with an excess of lactic acid remaining. When this 

 cream is churned the percentage of calcium, oxid in the salt- free ash 

 is increased because of the quantity of calcium lactate remaining in 

 the butter fat. It is probable that with excessive washing these cal- 

 cium salts could be washed out, but with the calcium would go the 

 flavor, a property the creamery man desires to keep in his product 

 as its value depends upon it, in large measure. Since the lime is 

 never added in excess, the butter will give a more or less acid reaction 

 to litmus paper. 



Storage butter is always acid even when not rancid. When it 

 is placed in a lime solution the free water-soluble acids that may 

 be present are neutralized to a greater or less degree. Since these 

 acids are perhaps one of the main causes of bad odor in rancid 

 butter, their neutralization will sweeten and deodorize the product. 

 The nonvolatile, nonsoluble acids, oleic and palmitic, play only a 

 secondary part in this process. These acids and their calcium salts 

 are practically insoluble in water and would be neutralized only in 

 small part. By using alcohol their presence in the free state can be 

 demonstrated. The calcium salts of the offensive water-soluble vola- 

 tile acids are more or less soluble in water and are removed partly 

 in the subsequent washing, the amount which remains depending 

 on the extent of the washing. Their presence can be demonstrated 

 by their odor on adding dilute sulphuric acid. Nor is the excess of 

 calcium hydroxid entirely removed, for all of the water extracts of 

 these butters gave an alkaline reaction to litmus. T^Hien such butter 



