



ihr tN ad f rk 
ei. A aN PERN i i 
0A LAMAR BS aS Uy 2 
ni a5 acl sf iy 
me 
wale, 
itty 
NAAN A 
v De 

New York AGRICULTURAL EXPERIMENT STATION. 983 ine 

acids. These changes occur mainly after the earlier stages of — 
ripening, No determinations of the amount of free fatty acids — 
have been made up to date, but they will be: made in the future 
analyses of the cheese. 
INFLUENCE OF THE RIPENING or CHEESE ON CASEIN. 
The casein in cheese undergoes various changes, forming, 
among other products, ammonia and soluble nitrogen compounds, 
which are probably peptones. 
About thirty years ago, Blondeau, a French chemist, and some 
others claimed that, in the ripening of cheese, the casein slowly — 
changed into fat. Muller, Sieber and Brassier have, however, 
shown that such a change does not take place. It is not uncom- 
mon, even in some of our standard authorities on physiology 
to-day, to see the erroneous conclusions of Blondeau referred to as 
undisputed facts. 
The nitrogen determinations made in the cheese under experi- 
ment were, for the first five weeks, (1st) the total casein, ete,and = 
(2d) the proportion of nitrogen compounds soluble in water. 
In these determinations, the same difficulty of sampling was 
found, as already mentioned. In some cases, the different sam- 
ples appeared to show an increase of casein, which could be 
accounted for only on the ground of a real difference in the sam-~ 
ples analyzed. In some cases, there was little change from week 
_. to week, while in others, there was a decrease in the amount of 
easein. a 
The soluble portion was determined by agitating about two aah 
grams of cheese with cold water, in the proportion of 100 
parts of water to one cheese. The insoluble portion was 
filtered off, washed, and then digested by the Kjeldahl method 
for nitrogen determination. The soluble portion was thus deter- 
mined by difference. While the results are not entirely concordant; 
they are of considerable interest in this connection, In the table 
below we present the data in two forms, giving first, the actual 
number of pounds of soluble nitrogen compounds in 100 
pounds of cheese ; and, second, the proportion of the total nitro- i 
gen compounds that were soluble in water. 4 





