ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

A.l.3
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acquired an increased status. The upmarket South African chain store Woolworths has
used indigenous knowledge provided to sell organically grown Amadumhe (Makgoba,
2004).
Fatty acids
Definition and structure
Fatty acids (caIboxylic acids) often have a long, branchless tail, with carbon atoms linked
in open chains (aliphatic). This chain can either be saturated or unsatmated. If the fatty
acid does not contain any double bonds or other functional groups along the chain, it is
termed saturated, whereas if it contains caIbon-eaIbon double bonds, it is called
unsaturated. If only one double bond is present, it is mono-unsaturated and with two or
more double bonds, it is polyunsaturated. Linoleic acid and alpha-linoleic acid are
essential fatty acids - that is, those which are needed by the body. These acids cannot be
synthesised by humans, but are widely distnbuted in plant oils (Fatty acid, 2008).
Occurrence and food sources
Fatty acids can occur as either free or bound forms. In the bound form, they are attached to
other molecules, such as in triglycerides or phospholipids (Fatty acid, 2008). Although fatty
acids are found in plants, animals and bacteria, they tend to be more complex in plants and
bacteria than in most animals (Fatty acids, 2008). Essential fatty acids provide practically
all the polyunsaturated fat needed by man. Omega-3 and Omega-6 fatty acids are drawn
from a diversity ofsources, which include fish, leafy vegetables, seeds from plants such as
pumpkins, chia and sunflowers, a variety of vegetable oils (for example: fIaxseedl1inseed
hemp, soya, canola/rapeseed) and nuts (for example: peanuts, walnuts) (Essential fatty acid,
2008).
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