Sept. 21, 1914 
Composition of Roquefort-Cheese Fat 
43 * 
the fat was shaken out three times in a separatory funnel with twice its 
volume of 95 per cent alcohol warm enough to keep the fat in a fluid state. 
There are certain objections to treating a fat with alcohol (Lewkowitsch, 
1909), but this seems to be the only practicable way of removing free 
acids insoluble in water. The fat was then washed three times with hot 
water to remove the alcohol, dried, and filtered clear. Fat treated in this 
way had a decinormal acid number for 10 grams of about 3.0, which is 
very nearly the same as the acid number of fresh, filtered fat of cow's 
milk. 
The Reichert-Meissl and the Polenske numbers were determined on 
these four samples of fat and also on a sample of cow's-milk fat, with the 
following results: 
Table IV.— Reichert-Meissl and Polenske numbers of the fats of Roquefort cheese and 
cow’s milk 
Source of fat. 
Reichert-Meissl 
number. 
Polenske 
number. 
Roquefort cheese: 
Blite. 
29. 62 
26. 72 
26.3s 
25. 64 
27. 27 
5 - 55 
6. 2? 
5. 68 
5. 60 
2. 00 
Roquefort Belier. 
Mialane et Cie. 
Louis Rigal.. 
Cow's-milk fat.. 
By direct distillation, as in the Reichert-Meissl number determination, 
only a part of the volatile acids are removed. The total quantity can be 
more nearly estimated by distillation with steam. Five-gram samples of 
two of the cheese fats and of the cow's-milk fat were saponified and dis¬ 
tilled with steam to 1,000 c. c. The titers of the soluble and insoluble 
adds are given in Table V. 
Table V .—Quantity of soluble and, insoluble volatile acids in 5 grams of Roquefort - 
cheese fat and of cow’s-milk fat determined by distillation with steam 
[Expressed in c. c. of N/io acid.] 
Source of fat. 
Soluble acids. 
1 
Insoluble acids. 
Roquefort cheese (Blite). 
41. OO 
38. 80 
36.OO 
18. 07 . 
19. 20 
II. 17 
Roquefort cheese (Mialane et Cie.). 
Cow ’s-milk fat. 
The physical properties and also the molecular weights of the insoluble 
acids showed that an acid of greater molecular weight than capric distilled 
over with the steam. In order to determine more accurately the quantity 
of each acid present, the distillate was divided into four fractions. The 
volatile acids of the first 500 c. c. of distillate constituted fraction 1, and 
the insoluble acids draining out of the condenser with this 500 c. c. of 
distillate formed fraction 2. Fraction 3 consisted of the soluble acids of 
the second 500 c. c. of distillate, and the remainder of the insoluble acids 
constituted fraction 4. The composition of fraction 1 was determined 
by a Duclaux distillation, and the compositions of fractions 2, 3, and 4 
1 
