Page 392 - Biosystems Engineering

Extraction, Refining, and Stabilization of Edible Oils 369

The 4-ketoeleostearic acid is present in the glycerides of oiticica
oil. Examples of fatty acids with double bond in a ring are chaul-
moogric and hydnocarpic acids. The glycerides of these acids are
found in chaulmoogra and similar oils of considerable therapeutic
values. These oils have antimetabolite properties and are effec-
tively used to combat leprosy and other external infections.

HOOC (CH ) – CH – CH – CH = CH
2 10 2 2 2
Hydnocarpic acid (C H O )
16 28 2
HOOC (CH ) – CH – CH – CH – CH = CH
2 12 2 2 2 2
Chaulmoogra acid (C H O )
18 32 2
Glycerides of very highly unsaturated fatty acids containing 20
and 22 carbon atoms and having up to 6 double bonds have been found
to be present in marine animal oils; 1.0 percent is found in human fat,
especially in the adrenal gland. It has the following structure:
20 15 14 12 11 9 8 7 6
CH (CH ) C H = C HCH C H = C H C H C H = C H C H C H
3 2 4 2 2 2
5 1
= C H – (CH ) C OOH
2 3
Arachidonic acid (C H O )
19 32 2
Only one hydroxy unsaturated acid ricinoleic acid (12-hydroxyoleic
acid) has been reported in natural fat. It is found in castor oil, which
is widely used for medicinal purposes (purgative) and for the pro-
duction of surfactants. It can also be converted to drying oil.
Oils are either edible or nonedible. Edible oils such as groundnut
and sunflower among others, are used for cooking purposes and
1
salad dressings. Nonedible oils are used in soaps, paints, and var-
nishes, politicizes, and similar products. About 1000 different fats
have been identified and characterized. One hundred fats are used
regularly and 12 of them constitute more than 90 percent of the
world’s vegetable oil production.

13.2 Determining Oil Content in Oil Seeds and Its
Extraction
Determining the oil content in oil seeds have been traditionally
accomplished using the soxhlet extraction method with different
2
organic solvents, as discussed by Lumley and Colwell. Improvements
in apparatus, sample preparation, and methodology for determining