ABSTRACT
Lipid classes and fatty acid composition (nutritive quality) of three commercially
important fresh water fish species Oreochromis Mossambicus (Mozambique Tilapia),
Clarias Gariepinus (Sharptooth Catfish) and Cyprinus Carpio (Carp) obtained from an
aquaculture, different river systems and fish markets in South Africa were investigated.
Fish fillets were prepared in the laboratory and used as representative samples for
extraction of lipids through the Folch extraction method (using chloroform methanol at
the ratio of 2:1). The structural separation of esterified fatty acids from fish lipids was
conducted using gas chromatograph. Identification of fatty acids (FAs) composition was
done by comparing the retention times of samples with the ones for all FAs standards and
by spiking with commercially available fatty acids standards. Total lipid content of
Tilapia fish was higher than that of Cat and Carp fish. Palmitic acid (16:0) was found to
be the most abundant fatty acid (18.24 to 21.84 %) in all analysed fish species.
Appreciable quantities of essential polyunsaturated fatty acids such as docosahexaenoic
acid DHA (22:6 n-3, 3.92 to 6.16%), eicosapentaenoic acid EPA (20:5 n-3, 1.91 to 2.92
%) and Arachidonic acid (20:4 n-6, 7.19 to 8.50 %) were also found. EPA + DHA values
were much higher on Tilapia fish lipid fractions in comparison with other fish lipid
fractions. Observations showed that fish species from Gauteng province were the richest
in lipid fractions as compared to those from other provinces. Of all fish species, cultured
fish were found to be highly characterised by high levels of FAs as compared to the fish
species collected from the river systems. This could be attributed to the FAs composition
of their diet. The study points out that all fish species under study contain appreciable
levels of n-3 polyunsaturated fatty acids and would therefore be suitable for highly
unsaturated low-fat diets.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/4822 |
| Date | 15 May 2008 |
| Creators | Chauke, Erasmus |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 4852297 bytes, application/pdf, application/pdf |
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