Omega -3 and Omega-6 Fatty Acids Potential of Smoked and Boiled Catfish (clarias Gariepinus)

Boiled and smoked catfish (Claria geriepinus) were evaluated in order to know omega-3 and omega-6 fatty acids potential of these processed fishes. Samples were analyzed for their fatty acids using modified AOAC methods and gas chromatography (gc). Findings shows that linoleic (&!-6), alpha-linolenic (&!-3) and gamma-linolenic were significantly higher in boiled catfish and covered respectively 9.0351 e-7 , 9.56501 e-5 and 2.76276 e-5 area when subjected to gas chromatography compared to the smoked cat fish. Also, both saturated and unsaturated fatty acids were present in appreciable amount in the processed samples. Therefore, catfish can serve as a potential source of essential fatty acids to human nutrition particularly in Nigeria where cat fish consumption is growing popular.

key words: Cat fish, Fatty acids, Omega-3 and Omega-6.intRODuCtiOn Catfish (Claria geriepinus) is an extensive freshwater fish, found virtually all over the world.It is a lean and highly nutritious fish that is rich in Vitamins, protein, and minerals, and has little or no saturated fat and is low in carbohydrate 1 .Catfish is sometimes eaten raw, but it is usually treated by various processes such as boiling, grilling, baking, frying smoking and oven drying before consumption.Heating (boiling, grilling, baking, and frying) is applied to food to enhance its flavour, tastes and to inactivate some pathogenic microorganism and increase its shelf life 2 .On the other hand, the use of microwave oven for drying has increased greatly during recent decades 3 .
O m e g a 3 a n d 6 fa t t y a c i d s a r e polyunsaturated fatty acids (PUFA), meaning they contain more than one is double bond.Although humans and other mammals can synthesis saturated fatty acids and some mono-saturated fatty acid from carbon groups in carbohydrates and protein.
It has been estimated that the ration of omega-6 to omega-3 fatty acid in the diet of early human was 1:1 4 but the ration in the typical western diet is now almost 10:1 due to increased use of vegetable oils rich in linolenic acid as well reduced fish consumption 5 .
Different cooking methods on proximate and mineral composition of catfish have been studied 6 .Drying is one of the oldest methods of preservative components of cell membranes.When incorporated into phospholipids, they affect cell membrane properties such as fluidity, flexibility, permeability and the activity of membrane bound enzymes.It plays important roles in vision and nervous system function.Drying of fish could extend the keeping quality thereby increasing the availability of fish year round, concerns have been raised about the appearance, texture, flavour, and importantly loss of some essential nutritional compositions.Therefore, this study seeks to determine the amount of saturated fatty acids and omega-3 & 6 fatty acids potential in smoked & boiled catfishes.

MAteRiAlS AnD MethODS
Tw o f r e s h l y h a r v e s t e d c a t f i s h (Clariageriepinus) were obtained from a nearby fish farm.The mean weight and length of the fish were 250-300g and 25-30cm respectively.The fish samples were washed with clean water to remove dirt, and were shared into two parts.One part was boiled in water and the other halve was smoked.The samples were dehydrated and blended separately using a kitchen blender; they were kept in labelled airtight containers andwere analyzed in the laboratory.The crude fat analysis was obtained by following the ether extraction method and fatty acids were analysed using gas chromatogram 7 .

ReSultS
The result in table 1 indicates the amount of saturated fatty acid in boiled and smoked catfish.Findings show that palmitic and Arachidic where significantly higher in boiled catfish which covered 1.92845 e-5 and 7.44878 e-7 amount/ Area when compared to smoked catfish which covered 1.92734 e-5 and respectively.
The result in table 2 shows the amount of unsaturated fatty acid in boiled and smoke catfish.
The study shows that linoleic, Alpha-linolenic and Arachidonre where significantly higher in boiled catfish which covered 9.03517 e-7 , 9.56501 e-5 and 1.73060 e-4 amount/area when compared to smoked catfish which covered 6.41263 e-4 , 5.45144 e-5 and 1.59797 e-4 respectively.

Fatty acid chromatogram for the processed catfish
Fatty acid chromatogram of the extracted fat content from boiled and smoked catfish are show in table 1 and 2. With reference to table 1 and 2 the fatty acids of the extracted fat content of clariasgariepinus are generally composed of saturated fatty acid and unsaturated fatty acid.Gas chromatogram illustrate that the boiled and smoked catfish samples have the common fatty acids such as oleic, arachidonic, eicosapentaenoic acid, stearic and docosahexaenoic acid.

DiSCuSSiOn
Although the result of this analysis work shows that alph-linoleic (&!-3) and linolenic (&!-6) of unsaturated fatty acid in boiled catfish is higher than that of smoked catfish.It was observed that about three quarter of the body weight of the catfish consist of water and therefore, an urgent step must be taken for its protection against destructive agent like microorganisms.In this study, more fat content were rapidly removed in the fish when subjected to smoking than boiling.This observation is in agreement with the finding of Andrew, (2001) (8) that boiled catfish generally achieved the required moisture content in food earlier and more uniformly than smoked catfish.