15/10/2018
For a long time wc have used inedible
animal fats and oils and products
made from them in a wide variety
of industrial applications^ many of
which have been modified only a little
since they were first developed.
But now the industry is entering an
era of expansion and development,
comparable to periods passed through
by both the petroleum and coal-tar industrieSj
in which emphasis is being
placed on isolating and preparing
chemically homogeneous substances.
This approach opens a tremendous
field for fundamental and applied research
and for the manufacture of
many new products. Such a trend
promises increased income to the
farmer, industrialist, and wage earner,
as well as many products to add to the
public comfort and health.
As industrial raw materials, it is the
inedible grades of animal fats and oils
that are used almost exclusively. Inedible
tallow and grease comprise
about 90 percent of these materials,
with pork fat and neatsfoot oil making
up the rest. Factory consumption of inedible
animal fats and oils in 1947 to
J 950 was about 2 billion pounds a year.
Inedible tallow comes mostly from
cattle and sheep as trimmings from
meat-packing plants or as scrap fats
obtained from meat trimmings in
butcher shops or saved in the kitchen
and sold to commercial rendcrers for
processing. A large amount of inedible
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pork fat is marketed as grease, an average
of about 5 pounds of grease being
produced for each hog slaughtered.
Other sources of grease are city garbage,
waste fat from restaurants and
hotels, and bones. When production of
lard exceeds the demand, a part of this
edible fat is diverted to grease.
Although grease is ordinarily considered
to be hog fat, and tallow the fat
of cattle and sheep, the commercial
distinction between greases and tallow^s
is made entirely on the basis of the titer
(the temperature at which solidification
occurs) of the fatty acids obtained
from the fat. If the titer is below 40°
C, the fat is a grease; above 40° C,
the fat is a tallow^
Inedible tallows and greases are
graded on the basis of color, content of
free fatty acids, and general quality—
flavor and odor. The important grades
of tallow, in order of quality, are:
Prime (Packers*) Tallow, produced
from the choicest inedible stock; Number
One Tallow, the most widely used
industrial grade; and Number Two
Tallow. The important grades of grease
are A White Grease, B White Grease,
Yellow Grease, and Brown Grease.
For most uses, the mateiials have
to be modified chemically. The only
important exception is neatsfoot oil,
w^hich is prepared from the feet and
shinbones of cattle and is used in lubricants
and dressings for leather. Only
3 million to 4 million pounds of neatsfoot
oil is produced annually, a relatively
small percentage of the total
quantity of inedible animal fats consumed
by industry.
The most important outlet for inedible
animal fats is in making soap,
a chemical process that has been conducted
for hundreds of years and for a
long time w^as almost the only outlet
for inedible animal fats. Soap accounts
for about 80 percent of the inedible
