NUTRITIONAL ANALYSIS OF SOME SELECTED FISH AND CRAB MEATS AND FATTY ACID ANALYSIS OF OIL EXTRACTED FROM PORTUNUS PELAGICUS
A.D Premarathna, R.P.V.J Rajapakse, E Pathirana, V.P Senaratne, S.C Karunarathna , A.P Jayasooriya
Keywords: Crab meat, Fatty acid, Protein, Proximate composition
Abstract: The meat of male P.pelagicus(n=3) was analyzed for protein, fat, moisture and ash contents by proximate analysis. The flesh of shark (Caracharhinus spp.)(n= 3),thalapath (Istiophorus spp.)(n= 3) were also analyzed for water-soluble protein content. Peptide-mapping was also carried out for the water-soluble protein fraction of all three types of samples. Moreover,the sub-samples (n=3) of the crab meat samples and commercial fish oil samples (n=3) were also analyzed for fatty acid profile and content, using gas chromatography. The results of proximate analysis revealed a composition of, 89.4±0.072 %( mean ±SE) moisture, 75.7±0.069% protein, 13.0±0.002% ash and 02.2±0.047% fat, in crab meat. The analysis water-soluble fraction revealed species-specific patterns on SDS-PAGE demonstrating greater amounts of myosin heavy chain and fimbrin compared to that of shark and thalapath flesh. As it was expected, a high content of polyunsaturated fatty acids were found in crab oil, representing 40.68 % of the total fatty acid content. The fatty acid profile exhibited greater percentages of oleic acid (28.03%) and eicosapentaenoic acid (EPA) (12.12%) when compared to existing data related to that of commercial fish oil. In conclusion, the study revealed high protein content and a low fat content in the meat of P. pelagicus. The water-soluble protein profile, meat of P. pelagicus could possibly be differentiated by peptide mapping which shows thick bands for the myosin heavy chain (MHC) and fimbrin. Oil of P. pelagicus carries relatively greater amounts of EPA and oleic acid. Thus, the consumption of crabs would help to prevent nutritional deficiencies in the future.
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