226 QUANTITATIVE AGRICULTURAL ANALYSIS

TABLE XX.—CONSTANTS OF BUTTER AND COMMON SUBSTITUTES

Butter fat
Oleomargarine*
Nut butter f

Iodine absorption number. . . Soluble acids ........
26-38 4.5
52-65 0.7
35.72

Insoluble acids ..........
87.5
95.5

Reichert-Meissl number ..... Polenske value .............
24-32 1.5-3.0
0.8-1.0 Less than 1
5-6.5 10-18

Saponification number ......
220-233
195
225-250

Index of refraction ........
1.454
1.458

Butyro refractometer reading
42.0
48.0
43.5

* A representative oleomargarine made from oleo oil, lard and milk,
f Made from peanut and cocoanut oils.

FIG. 50.—Steam or hot water funnel.
Preparation of Samples of Butter Fat.—Melt the butter at
60° and keep at this temperature for several hours, or until the
curd and water have separated completely. Pour off the clear
fat through a dry filter paper which is placed in a hot water or
steam funnel (Fig. 50).
For the general methods to be used in the examination of
butter fat refer to Chap. X, on fats, oils and waxes.
CHEESE
According to the Federal standard, cheese is the sound, solid
and ripened product made from cream or milk by coagulating the
casein with rennin or lactic acid, with or without the addition of