Nov. 26,1917 
Enzyms of Milk and Butter 
447 
All the samples gave some color change, but for the storage butters 
and the pasteurized creamery butter it was very slight. Milk diluted 
1 to 160 with distilled water and to which 16 per cent of boiled milk was 
added gave a gray color similar to that of the fresh dairy butter; hence 
the peroxidase content of butter is very small. 
COMPARISON OF MILK AND BUTTER ENZYMS ON THE BASIS OF TOTAL 
NITROGEN 
The fat in butter acts as so great a diluent for the water-soluble con¬ 
stituents that a direct comparison of the enzyms of milk and butter 
is misleading. The more logical comparison is on the basis of the total 
nitrogen, since the proteins and enzyms exist in the same colloidal 
state and ought to be carried into the butter in the same proportions 
as they exist in the cream. The total protein of the fresh dairy butter 
was 0.55 per cent, that of the milk from which it was made 3.47 per 
cent, so the enzymic activities in the butter were multiplied by 6.31. 
On taking the milk as the standard and its enzymic content as 1, butter 
was found to contain the following amounts of the various enzyms 
which were studied: 
Galactase. 1.100 Catalase. 2. 000 
Oxidase. 0.000 Peroxidase. 0.008 
The galactase content of the butter was approximately equal to that 
of the milk, the catalase content was double, but the peroxidase content 
was very much less, and no oxidase activity could be detected. 
RELATION OF ENZYMS IN BUTTER TO DETERIORATION DURING 
STORAGE 
As mentioned in the introductory paragraphs of this paper, dete¬ 
rioration in quality of butter during storage has been considered by 
some investigators to be due to the action of enzyms contained in it. 
Fat-splitting (lipase) or protein-hydrolyzing (“galactase” or casease) 
enzyms have been suggested as possible agents in causing deterioration. 
Our work leads us to conclude that lipases are present in butter in very 
small amounts, if at all, and that they could not be conceived to be 
sufficiently active at the low temperature used in butter storage to 
cause any appreciable change in the quality of the butter. The protein¬ 
hydrolyzing enzym we found to be completely inhibited by sodium 
chlorid in the concentrations which are present in the water contained 
in all normally salted butters. This fact, together with the known 
inhibiting effect of low temperatures upon proteolysis by enzyms makes 
it impossible that the hydrolysis of proteins in the butter by enzyms 
plays any part in deterioration changes. We conclude, therefore, that 
enzyms are not to be considered as a factor in the deterioration of butter 
in cold storage. 
