Fatty acids and fat soluble vitamins content of Black Sea round goby (Neogobius melanostomus, Pallas, 1814) during fishing seasons

The aim of the present study was to determine and compare the seasonal changes in proximate composition, fatty acid profile and fat soluble vitamins content in spring and autumn goby (Neogobius melanostomus) caught from the Bulgarian Black Sea waters. Proximate composition (moisture, protein and total lipid) was determined according to AOAC (1991).  Analysis of fatty acid methyl esters was performed by GC/MS system. Vitamins A, D3 and E were analysed simultaneously using RP-HPLC system. Protein was in the range 18.10 – 18.75 %, fat content was: 1.60 - 2.61g.100g-1 wet weight (w.w.). The fatty acid (FA) and vitamins contents showed significant seasonal changes. The spring goby was characterized with low saturated fatty acid (SFA, 31.8 %), high mono unsaturated fatty acids (MUFA, 34.86 %) and polyunsaturated fatty acids (PUFA, 33.34 %). In both seasons omega-3 (n-3) PUFA levels were higher than omega-6 (n-6) PUFAs. Higher amounts of alpha-tocopherol (614.9 μg.100g-1w.w.) and all-trans retinol (14.8 μg.100 g-1w.w.) were found in autumn samples, whereas cholecalciferol (4.9 μg.100 g-1w.w.) - in spring goby. Regardless of the observed seasonal changes of nutritional quality, goby species is an excellent source of analysed components, especially of n-3 PUFA, and can be recommended for healthy human diet.