Apr. 15.1914 
Flavor of Roquefort Cheese 
11 
Table VII .—The effect of Penicillium roqueforti on the fat of fresh curd. 
Condition. 
Age. 
Reichert- 
Meissl number 
for 2.5 grams. 
Decinormal 
acid number 
for 10 grams. 
Molecular 
weight of the 
insoluble 
fatty acids. 
Uninoculated control. 
Days. 
36 
36 
85 
16. 05 
12. 74 
7. 87 
2. 3 
269.3 
271.3 
269. 4 
Inoculated. 
66. 7 
Do . 
163.7 
As in the previous culture on Czapek’s solution, the fat showed decided 
decomposition, but there was only a meager accumulation of soluble and 
volatile acids. A culture at the age of 45 days contained only 0.75 deci- 
normal c. c. of soluble acids in 500 c. c. of distillate. A culture similarly 
grown but in the presence of Bacillus ladis acidi contained only 0.80 
decinormal c. c. of soluble acids in a like volume of distillate. The acid 
number of the fat in both cultures showed that more than one-half of it 
had been hydrolyzed. 
Just why these acids accumulate in a cheese but not in a culture grown 
upon green curd is not obvious. The growth of mold in the crevices of 
the cheese is always very scant in comparison with the growth of a culture 
having an unlimited supply of oxygen (Thom and Currie, 14, p. 249). 
The gas within the cheese frequently contains less than 5 per cent by 
volume of oxygen. This very limited supply of oxygen may hinder the 
metabolic functions of the mold and prevent the complete oxidation of 
butyric and caproic acids. 
Another explanation, and to the writer this appears the more probable 
one, is to be found in the presence of a water-soluble enzym which diffuses 
beyond the feeding zone of the mold. An examination of a Roquefort 
cheese will always show that the central portion is much more open in 
texture and more thoroughly permeated with mold than the outer por¬ 
tion. In fact, a layer about 2 cm. in thickness next to the rind is almost 
free from mold. This portion, although not so highly flavored as the 
more moldy portion, is always sufficiently ripened to be entirely palatable. 
The inner portion of a very ripe cheese gave a distillation number of 
88.3 and this outer portion, 60. This thorough ripening in portions of 
the cheese where only small and scattered pockets of the mold are visible 
is apparently due to water-soluble enzyms, among which is an active 
lipase. 
ENZYMOTIC STUDIES 
In order to obtain definite proof of the presence of a water-soluble 
lipase, enzymotic studies were made on the mycelium of Penicillium 
roqueforti grown for six days upon Czapek’s solution. Ethyl butyrate 
to the extent of 0.5 c. c. per 100 c. c. of medium was added. Dox (4, p. 
149) has shown that the addition of a particular substrate to a medium 
