Nutritional evaluation in five species of tuna

Abstract

Proximate composition was determined in different body parts (skin, white muscle, red muscle, head muscle and belly flap of five species of tuna; Katsuvonus pelamis (skipjack, balaya), Thunnus Albacares (yellow fin tuna, kellawalla), Auxis rochei (Bullet tuna, ragoduwa), Auxis thazard (frigate tuna, alagoduwa) and Euthvnnus affinis (kawakawa, attawalla) obtained from the Negambo fish landing site. Fatty acid profiles were also analyzed in the akin, red and white muscle of the five species. No significant differences between the tuna species were observed with respect to protein, total fat. and moisture contents. The ash content in Frigate tuna and Kawakawa were significantly higher than the other species. The muscle tissue in all the species was rich in protein (20-25%) and low in fat (<2%). The skin of all the species recorded high protein (27-32%) and lipid (6-8%) levels. The moisture content was low in the skin compared to the other tissues. All five species of tuna studied here recorded less SFA (11-33%) and more PUFA (50-74%) in the muscle tissues. The MUFA content in muscle tissue ranged from 8-25% and all the species contained both EPA (eicosapentaenoic acid, C20:5 n-3) (2-19.7%) and DHA (docosahexaenoic acid, C22:6 n-3) (4-42%) in varying amounts.

Key words: Tuna, proximate composition, n-3 fatty acids, n-6 fatty acids, EPA, DHA