Fatty acids and amino acids contents in Scomber scombrus fillets from the South East of Tunisia
Proximate composition, fats and amino acids of Atlantic Mackerel fillets (Scomber scombrus) from the South East of Tunisia in different seasons, were analyzed in order to assess nutritive characteristics of this species. Samples were collected monthly from Zarzis fishing port located in the South-East of Tunisia. Total fats and protein contents varied significantly (P<0.05) according to the season. The highest values were obtained in spring (11.53 and 24.1% DM, respectively). Gas chromatography analysis showed the existence of saturated (SFAs), monounsaturated (MUFAs) and polyunsaturated (PUFAs) fatty acids. Palmitic and stearic acids were the major fatty acids in SFA family. Palmitoleic and oleic acids were the predominant in MUFA family. Arachidonic acid was the dominant in n-6 PUFA family. While eicosapentanoic (EPA) and docosahexanoic (DHA) were the most abundant in n-3 PUFA series. We observed that high PUFAs percentages were related to those of n-3 PUFA family, mainly DHA which was present at a high level and varied significantly with season (P< 0.01) with the highest value in winter (40%). The n-6 PUFA series were present at low rates comparatively with those of n-3 PUFA series ranging between 4.5 and 5.7%. The highest level of n-6 PUFAs was observed for arachidonic acid in autumn 3.71%. The n-3/n-6 ratio exhibited the highest level in spring (11.02). The Atlantic Mackerel fillets were high in essential amino acids (34.59 g/100 g of proteins). The highest rates were noted for phenylalanine, valine, threonine, isoleucine, leucine and methionine. It was concluded that Atlantic Mackerel was high in interesting human feeding nutriments, mainly PUFA and essential amino Acids. Even when significant, differences between seasons were not drastic and S. scombrus could be consumed during all the year.
Keywords: Scomber scombrus, lipids, fatty acids, amino acids, seasonal variation