unsaturated oils. Both require care

unsaturated oils. Both require careful handling to prevent rancidity due to oxidation. The super-unsaturated
fatty acids are molecules with three kinks (Fig. 7). These
are found mostly in fish tissue and in the seeds of black
currant, evening primrose, and flax plants. These must
be carefully protected to preserve their nutritional qualities.
Fats consisting of highly saturated or long chain fatty
acids will generally have a higher melting point than
those possessing a high content of unsaturated or short
chain fatty acids. Unsaturated fatty acids can have different isomeric forms which have different melting
points. They naturally exist in thecis-form, but can be
converted into the trans-form during partial hydrogenation (Dziezak, 1989). Crystalline forms in which
fats may exist may be categorized as alpha-, beta-, and
beta-prime. This classification will be dealt with below.
Weiss (Weiss, 1983)classified a number of fats according to their crystallizing nature as shown in Table 6.A
large number of oils and fats are available which are
classified based on their source and consumption (Dziezak, 1989; Formo, Jungermann, Norris, & Sonntag,
1979a). Below are a number of fatty acids types by
which fats are also characterized, as well as source and
consumption classifications.
1. Linolenic acid group
Oils of this group contain appreciable amounts
of linolenic acid but may also contain oleic acid
and linoleic acid. Flaxseed oil and soybean oil,
with its 7% linolenic acid content, is the best
example of this group.
2. Oleic-linoleic acid group
The examples of this group are cottonseed, olive
oil, palm, peanut, sunflower, and safflower oil.
Cottonseed oil consists of 73% of unsaturated
fatty acids. The oil palm (Elaeis guineensis)isa
native of West Africa. Palm oil contains equal
amounts of saturated and unsaturated fatty
acids