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 the proximate composition, fatty acids profile and fat soluble vitamins content in spring and autumn goby (Neogobius melanostomus) caught from the Bulgarian Black Sea waters. The proximate composition (moisture, protein and total lipid) has been determined according to AOAC (1990). Analysis of fatty acid methyl esters has been performed by GC/MS system. Vitamins A, D3 and E were analysed 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 acids (FA) and vitamins contents showed significant seasonal changes. The spring goby was characterized with low saturated fatty acids (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 100g-1 w.w.) were found in autumn samples, whereas cholecalciferol (4.9 μg 100g-1 w.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.