DAIRY PRODUCTS

225

It differs from butter fat mainly in the larger proportion of the
volatile fatty acids that are insoluble in water. These differ-
ences are used in its detection,, especially trie volatile insoluble
fatty acids as indicated by the Polenske value (page 186) , which
is the number of cubic centimeters of tenth-normal base required
to neutralize the insoluble volatile fatty acids obtained from
5 gm of fat. The Polenske value for butter is 1.5 to 3.0, for
oleo oil 0.5 and for cocoanut fat about 17. The average Reichert-
Meissl number for cocoanut fat is about 7, while that of butter
fat is about 28. This makes it possible to distinguish (a) between
butter and butter substitutes and (6) between oleomargarine and
"nut" butters. The fatty acids of the glycerides of cocoanut
fat are as follows:1

TABLE XIX. — FATTY ACIDS OP GLYCERIDES OF COCOANUT FAT

Acid

Per cent

Caproic .............
2

Caprylic ..................
9
• Volatile but largely insoluble

Cap ric
10

Laurie ... ........
45

Myristic .................
20

Btearic .....................
5
- Non-volatile

Oleic ...........
2

Palmitic ...............
7

N:

*H .

!

f'

ii

The particular "constants" that are mentioned in the following
table will be found of greatest value in identifying butter and
butter substitutes. Of these the Reichert-Meissl number, the
Polenske value and the soluble acid number are perhaps of
first importance. Microscopic examination will serve to dis-
tinguish process butter, by the fact that fat crystals are to be
found only in butter that has been remelted.

L ELSDON, Analyst, 38, 8 (1913).