2. REPORT
IN
T.L.E iv
JAMILENE f.PANDAN
iv-GARNET
mrs. Encierto
3. SHORTENING
I. CLASSIFICATION OF SHORTENINGS
A. ANIMAL FATS
1. Lard and Lard Oil
Lard needs little introduction to bakers. It is well known as an excellent
shortening and is used extensively in the manufacture of quality bakery
products.
The fat of hogs is separated by a heating process known as rendering. The
melted fat is then allowed to cool and solidify under controlled conditions. The
resulting product is a pure white fat of pleasing taste and odor, known as lard.
There are different types of lard depending on the part of the hog from which
the fat is secured, and also on the process of rendering and cooling.
Lard is made up of a mixture of stearin, palmitin and olein. When lard is
melted it becomes liquid. If this liquid is allowed to cool slowly, the harder fat
or stearin separates out first. At this point, the oil which remains can be
strained off and thus separated from the stearin. This oil consists mainly of
olein and is termed “lard oil.” It is this lard oil which is claimed to impart the
pleasant flavor contributed by lard to bakery products.
For years lard has been used as shortening in bakery products due to its
excellent shortening power, purity, whiteness, and pleasing mild taste and
odor as well as its excellent keeping qualities. Lard is easily handled in the
bakery and because of its desirable consistency, it mixes easily into the dough
batch.
2. Leaf Lard
Leaf lard is usually considered as the highest grade, and is obtained from the
fat surrounding the kidneys, and rendered at a moderately high temperature.
However, much of the high quality lard now produced is secured from other
sections of the animal as well.
3. Different Types of Lard Classified According To Manufacturing Method
4. The main difference between the various types of lard are governed by the
method of manufacture, and handling. Two commercial types of lard are as
follows:
(a) PRIME STEAM LARD
This lard is usually rendered from fats obtained from all parts of the hog. The
fat is first melted by means of steam, and drawn off. If the melted fat is
allowed to cool down gradually without stirring, the lard thus secured will have
a relatively coarse grain.
If, however, the melted fat is chilled very quickly until it just starts to become
solid,—and is then agitated or beaten and allowed to set,—the lard thus
secured will be very smooth and not at all granular or grainy.
(b) KETTLE RENDERED LARD
This type of lard is usually made from the “leaf” and back fats. Due to the fact
that these fats contain more stearin than other hog fats, this type of lard is
usually harder than other types of lard. Kettle rendered lard is heated to a
somewhat lower temperature than steam rendered lard and is usually cooled
with very little agitation, resulting in a lard which is uniform and somewhat
grainy in character.
4. Beef Fats
By a process of melting, pressing and filtering, beef fat or tallow, can be
separated into hard fat known as oleo-stearin, and soft fats or oils known as
“oleo.”
The oleo oils whidh are pressed out of the beef fat are used extensively in the
manufacture of oleomargarine. The oleo stearin is used in the preparation of
Compound shortenings.
5. Butter
Butter is the fat of milk separated from milk or cream by churning and contains
also a small amount of other milk constituents. The U. S. standards for butter
state that it must contain not less than 80 % of milk fat. The remainder of
butter is made up largely of water, together with a very small amount of casein
(milk protein), salt, milk sugar and certain substances which impart the
delightful characteristic flavor to butter which is found in no other fat.
5. Salted butter may contain various amounts of salt ranging from about
1/2% about 6%.
In products where appreciable amounts of butter are used, the salt content of
the butter should be taken into consideration, and any necessary adjustment
on account of this should be made. In yeast raised sweet doughs, butter
which is rolled into the dough should first be washed with cold water to
remove the salt present.
Because of its composition and low melting point butter is very easily digested
and like other edible fats is a concentrated fuel food for the human bodfr.
Furthermore, butter is one of the richest sources of vitamin A, an essential
food factor which is necessary for normal growth, teeth and bone
development.
Butter is used mainly in cakes and pastries, because of the excellent flavor
and food value which it imparts to the finished product.
B. VEGETABLE SHORTENING
1. Vegetable Oils
Certain vegetable oils, principally those pressed from corn, cocoanut and
cotton-seed have been used to some extent for baking purposes. For such
use, these oils are refined, bleached and deodorized.
Vegetable oils are not used to any extent in pastries due to the fact that a
solid fat is more desirable for such purposes. While these oils as such can be
used for shortening purposes in breadmaking, they are more likely to become
rancid and are not so easily handled as solid fats. This fact was recognized
years ago and therefore vegetable oils were frequently blended with harder
fats so as to form a solid soft fat mixture known as compound. In later years a
process of treating such oils with hydrogen so as to produce an ideal solid
vegetable shortening was discovered.
Compounds and hydrogenated shortenings are described in the paragraphs
which follow.
Highly refined cottonseed oil or corn oil, however, is used to a considerable
extent in the frying of doughnuts and similar products because of the “fact that
they can be heated to a higher temperature than lard without smoking, and
yield a fried product which is dry and free from greasiness.
6. 2. Hydrogenated Vegetable Shortenings
Some years ago it was discovered that if hydrogen gas were circulated
through the ordinary vegetable oils at a high temperature and under certain
other necessary controlled conditions, they would gradually be changed into a
solid fat. This change is due to the fact that the olein and linolin which are the
principal constituents of such oil, absorb the hydrogen and are thereby
converted into the solid fat, stearin. The longer the hydrogen is passed
through the oil, the more will be absorbed and the harder and whiter, the
resultant fat will become; because a greater amount of the fluid olein and
linolin is thus converted into vegetable stearin. This process is used
extensively today in converting oils into solid fats and is known as the
“Hydrogenation of oils.” The hardness of any hydrogenated oil can be
governed by the extent to which it is hydrogenated. The complete
hydrogenation of a vegetable oil would change it into a fat which would be far
too hard for satisfactory use as a shortening agent. Therefore in order to
secure a product having the proper degree of hardness or consistency such
as that of lard,—vegetable oils are only partially hydrogenated, so that only
enough of the linolin and olein are hardened thus producing a shortening of
the desirable plasticity. It can be easily seen that the discovery of the
hydrogenation of oils was very valuable for it meant that oils could be readily
converted into solid or semi-solid shortenings. There are many brands of
excellent hydrogenated fats extensively used in practically all types of bakery
products today and the value of this class of shortenings is well known to the
bakery industry.
C. COMPOUNDS
“Compounds,” as the name signifies represent that group of shortenings made
by compounding or blending a vegetable oil with a hard fat in proper
proportions so as to give a resulting product of a desirable consistency such
as that of lard. Thus cottonseed oil, corn oil or other vegetable oil blended with
vegetable or animal stearin, in a suitable manner forms a compound
shortening, which is white, odorless and of plastic consistency.
The animal stearin used in the manufacture of compounds is usually oleo-
stearin or the hard fat secured from tallow. Today this is often replaced by
vegetable stearin secured by hydrogenating vegetable oil as previously
described.
7. D. OLEOMARGARINE
Oleomargarine is well known as “artificial butter” or butter substitute. It is
usually made of refined oleo oil churned in with some pure butter, neutral lard,
and milk. Sometimes vegetable oils, such as cottonseed oil are also used.
Cocoanut oil is often used in the preparation of various kinds of so-called “nut
butter or nut margarine.” Oleomargarine is pure and wholesome. Its
shortening power is excellent and its flavor resembles that of butter.
II. DEFINITION
Shortening refers to the fats or oils used in baked goods, principally to
produce a soft velvety crumb, thus improving the eating quality of the finished
product. This desirable tender and pleasing eating quality is described by the
word “short” and the fats or oils which impart this property are therefore known
as shortenings.
III. COMPOSITION OF SHORTENINGS
While the various shortenings commonly used may be quite different in their
consistency, melting points and other physical properties, they are very similar
in chemical composition. Thus ordinary shortenings when analyzed are found
to be mixtures containing some of the following substances in various
proportions:
1. STEARIN—a hard fat, naturally of animal origin. Vegetable stearin may
be secured by saturating vegetable oils with hydrogen gas as described
later under the subject of “Hydrogenated Vegetable Shortenings.”
2. PALMITIN—a fat, secured from both animal and vegetable sources.
3. OLEIN—an oil secured from both animal and vegetable sources.
4. LINOLIN—an oil present in cottonseed oil.
IV. FATS AND OILS USED AS SHORTENING
Shortenings ordinarily used for baking purposes are edible fats or oils of
vegetable or animal origin. The dividing line between these fats and oils is not
very definite. In general, shortenings which are fluid at ordinary temperatures
are called oils, and those which are solid are called fats. Some fats however,
have higher melting points and are harder than others. Thus, we have what
are known as hard and soft fats. The usual forms of solid shortenings used at
the present time represent various mixtures of hard and soft fats.
8. V. STORAGE OF SHORTENING
Light, warmth, air and moisture favor the development of rancidity in fats and
oils. Therefore, shortening, in storage, should be kept tightly covered, in a
cool, dark, dry place.
VI. KEEPING QUALITIES OF SHORTENING—RANCIDITY
EXPLAINED
The ability of any shortening to retain its freshness and sweetness is of utmost
importance in the manufacture of quality baked goods, for if any fat or oil
becomes slightly rancid and is used, it will impart to the finished product a
disagreeable taste and odor which is even more objectionable to the
consumer than ordinary staleness.
Today the baker is fortunate in being able to secure solid shortenings which
are quite resistant to the development of rancidity provided they are stored in
a dry, cool, dark place, in containers which are tightly covered.
If the causes for rancidity in oils and fats are understood, the importance of
the careful selection of shortening and the proper storage of the same can be
better appreciated.
On standing for a period of time, exposed to air and light, the ordinary edible
fats and oils have a tendency to become rancid. This is evidenced by the
development of an objectionable odor and gummy consistency in the
shortening and is due to the fact that these fats and oils absorb oxygen from
the air resulting in the formation of certain oxidation products which possess
an objectionable taste and odor.
Shortening in this condition is obviously unfit for baking purposes. As
explained previously, shortenings ordinarily used contain various proportions
of the solid fat substances known as stearin and palmitin together with the
fluid constituents, olein and linolin. Now pure stearin and pure palmitin alone
are too hard for satisfactory use as shortening; however, it is significant to
note that both stearin and palmitin are very stable and will not become rancid
or gummy on standing. This is due to the fact that neither of these solid fat
substances will absorb oxygen from the air, and because of this stearin and
palmitin are said to be “saturated” fats.
9. On the other hand, the other two substances present in shortenings namely,
the oils, olein and linolin will absorb oxygen from the air and are therefore said
to be “unsaturated.”
Hence, the greater the amount of stearin or palmitin contained in any
shortening, the harder it is, and the less liable it is to go rancid on standing.
For instance: lard contains more stearin and less olein than cottonseed oil.
Therefore lard will not become rancid as readily as cottonseed oil. As
previously explained, by hydrogenating cottonseed oil, some of the olein and
linolin are thereby converted to stearin.
Thus the solid shortenings produced by the hydrogenation of vegetable oils
are much less likely to become rancid on standing than the oils if permitted to
remain in their original natural fluid state.
In addition to the development of rancidity in shortenings resulting from the
process of oxidation as described above, butter may go bad on standing due
to certain bacterial action which results in the liberation of butyric acid and
other acids which give it a disagreeable taste, making its use in baked goods
impossible.
VII. MARKET FORMS
Originally, shortening was synonymous with lard, and with the invention
of margarine by Frenchchemist Hippolyte Mège-Mouriès in 1869, margarine
also came to be included in the term. Since the invention of hydrogenated
vegetable oil in the early 20th century, "shortening" has come almost
exclusively to mean hydrogenated vegetable oil. Vegetable shortening shares
many properties with lard: both are semi-solid fats with a higher smoke
point than butter and margarine. They contain less water and are thus less
prone to splattering, making them safer for frying. Lard and shortening have a
higher fat content compared to about 80% for butter and margarine. Cake
margarines and shortenings tend to contain a few percent
of monoglycerides whereas margarines typically have less. Such "high ratio
shortenings" blend better with hydrophilic ingredients such
as starches and sugar. Hydrogenation of organic substances was first
developed by the French chemist Paul Sabatier in 1897, and in 1901 the
German chemist Wilhelm Normann developed the hydrogenation of fats,
10. which he patented in 1902. In 1907, a German chemist, Edwin Cuno Kayser,
moved to Cincinnati, Ohio, the home town of US soap manufacturer Procter &
Gamble. He had worked for British soap manufacturer Joseph Crosfield and
Sons and was well acquainted with Normann's process, as Crosfield and
Sons owned the British rights to Normann's patent. Soon after arrival, Kayser
made a business deal with Procter & Gamble, and shortly thereafter
presented the company with two processes to hydrogenate cottonseed oil,
with the intent of creating a raw material for soap. However, since the product
looked like lard, Procter & Gamble instead began selling it as a vegetable fat
for cooking purposes in June 1911, calling it "Crisco", a modification of the
phrase "crystallized cottonseed oil".
VIII. DIFFERENT KINDS OF SHORTENING
1. Solid Shortening - recommended for use in bread dough because it can be
more thoroughly distributed through the dough.
2. Liquid Shortening - mainly used in recipes that call for melted shortening,
such as some cake and bread recipes.
