Effect of frozen storage on fat soluble vitamins content in fish fillets

Fat-soluble vitamins content (all-trans-retinol, alpha-tocopherol and cholecalciferol) in edible tissue of Bluefish (Pomatomus saltatrix), a typical Black sea pelagic fish, and in Rainbow trout (Oncorhynchus mykiss), a typical farmed freshwater fish, were determined and compared on raw state and after frozen storage. The sample preparation procedure includes saponification and consequent extraction of fat-soluble vitamins with n-hexane.The extract was dried under nitrogen flow and redissolved in methanol. HPLC analysis of methanolic samples was performed on ODS2 Hypersil (250x4,6, 5um) column with a mobile phase of methanol:water = 97:3. The quantification of fat-soluble vitamins was by the method of standard addition. Retinol and cholecalciferol were monitored by UV detection and alpha-tocopherol was detected by fluorescence.The retinol and cholecalciferol contents in fresh edible tissue of Black sea Bluefish (38.5±2.4 μg.100g-1ww and 11.2±1.2 μg.100g-1ww, respectively) were close to values in the freshwater fish Rainbow trout (58.9±2.6 μg.100g-1ww and 14.9±1.1 μg.100g-1ww, respectively). Alpha-tocopherol content was several fold higher in Rainbow trout (1648.9±68.8 μg.100g-1ww) than in Black sea Bluefish (427.1±37.1 μg.100g-1ww).Long period of storage affected mostly retinol and alpha-tocopherol contents in two fish species. While cholecalciferol content remained almost unchanged

Assessment of Proximate and Bioactive Lipid Composition of Black Sea Mussels (M. galloprovincialis) from Bulgaria

Farmed marine mussels from genera Mytilus are important for the human diet by providing high levels of proteins, omega-3 polyunsaturated fatty acids (PUFAs), fat soluble vitamins and carbohydrates. Recently, black mussels are commercially important species from the Bulgarian Black Sea. The aim of this study was to assess the seasonal changes in proximate composition and to focus on the lipid bioactive components such as fatty acids, cholesterol, fat-soluble vitamins (A, E and D3), and carotenoids (astaxanthin, beta-carotene) in farmed mussels (M. galloprovincialis) from the northern part of the Bulgarian Black Sea coast. All analyzed samples presented high protein and low lipid content. The fatty acids (FA) profile was characterized by the highest amount of PUFA, as 22:6 omega-3 (n-3) dominated, regardless of the seasons. In all seasons, the content of n-3 was significantly higher than the omega-6 PUFA. The amounts of cholesterol were in the range 62.3 (summer) to 78 (autumn) mg 100−1 g ww. The highest amounts of vitamin D3 (3.1 μg 100−1 g ww), vitamin E (2525 μg 100−1 g ww), astaxanthin (0.470 mg 100−1 g ww), and beta-carotene (0.445 mg 100−1 g ww) were found in the summer season. The studied mussel aquaculture from Bulgaria presented a high beneficial potential in all seasons in terms of human health protection

BLACK SEA RAPANA VENOSA – A PROMISING SOURCE OF ESSENTIAL LIPIDS

Background: A diet rich in seafood has been linked to a variety of health benefits. While worldwide overfishing results in declining fish stocks, the growing demand for alternative sources of marine lipids has been expected. Rapana venosa (veined Rapa whelk) has become valuable seafood with nutritional and economic importance in the Black Sea region. Purpose: The aim of the present study was to provide knowledge about biologically active lipids in Black Sea Rapana venosa, harvested in the region of Varna. Material/Methods: Lipid classes were separated and purified by column and thin-layer chromatography. The saponifiable lipid fraction was derivatized into fatty acid methyl esters (FAMEs) and analysed by gas chromatography–mass spectrometry (GC-MS). Non-saponifiable lipids were identified by high pressure liquid chromatography coupled with UV/Vis and fluorescence detectors (HPLC-UV-FL). Results: Rapana venosa was characterized by low lipid content (0.50 g.100g-1 ww) with beneficial PUFA/SFA and n-6/n-3 ratios and high content of vitamin D3 and astaxanthin. Lipids comprised mainly of polar lipids. Polyunsaturated fatty acids represented more than 50% of total fatty acids, most abundant being from the omega-3 series. Sum of EPA and DHA accounted at 40.8% of total fatty acids. Lipid quality indices indicated the good anti-atherogenic and atni-trombogenic properties (AI and TI < 1) of rapana meat. Conclusions: The study revealed that Rapana venosa from the Black Sea is a good source of high quality marine lipids and presents а high potential for developing functional foods and/or dietary supplements with beneficial health effects

Bulgarian Marine and Freshwater Fishes as a Source of Fat-Soluble Vitamins for a Healthy Human Diet

The aim of the present study evaluates the fat-soluble vitamins all-trans retinol (vitamin A), cholecalciferol (vitamin D3) and α-tocopherol (vitamin E) content in the fresh edible tissue of Bulgarian fish species: marine—grey mullet (Mugil cephalus) and bonito (Sarda sarda), and freshwater—rainbow trout (Oncorhynchus mykiss) and common carp (Cyprinus carpio). The sample preparation procedure includes alkaline saponification, followed by liquid-liquid extraction with n-hexane. All-trans retinol, cholecalciferol and α-tocopherol were analyzed simultaneously using RP-HPLCUVFL system with analytical column C18 ODS2 Hypersil™. The fat soluble vitamins content (μg per 100 g wet weight) in the fresh edible fish tissue of analyzed fishes are in the ranges: vitamin A from 2.7 ± 0.4 to 37.5 ± 3.4 μg/100 g ww; vitamin D3 from 1.1 ± 0.1 to 11.4 ± 0.6 μg/100 g ww; vitamin E from 121.4 ± 9.6 to 1274.2 ± 44.1 μg/100 g ww. Three fat-soluble vitamins occur in higher amounts in rainbow trout and grey mullet species. According to recommended daily intake (RDI), they are a good source of cholecalciferol

Can Fish and Shellfish Species from the Black Sea Supply Health Beneficial Amounts of Bioactive Fatty Acids?

Fatty acids (FA) are among the most important natural biologically active compounds. A healthy diet involves the intake of different fatty acids especially from omega-3 (n-3) series. Seafood provides a very good source of polyunsaturated fatty acids (PUFAs), but in Bulgaria there is limited information regarding the n-3 PUFA contents in traditionally consumed seafood by the population. The aims of this study were to determine lipid content, omega-3 polyunsaturated fatty acids (EPA and DHA), and the recommended daily intake of eleven fish species, three bivalves, rapana, and shrimp harvested in the Western part of Black Sea, Bulgaria. Total lipids were extracted according to the method of Blight and Dyer and fatty acid composition was analyzed by GC/MS. Fatty acid profile showed differences among species. PUFA were found in high content among total lipids, especially in shellfish (60.67–68.9% of total lipids) compared to fish species (19.27–34.86% of total lipids). EPA was found in higher amounts in rapana (0.16 g/100 g ww) and two of pelagic species (up to 0.29 g/100 g ww), whereas DHA prevailed in demersal and the most of pelagic fish (0.16–1.92 g/100 g ww) and bivalves (0.16–1.92 g/100 g ww). The health beneficial n3/n6 and PUFA/SFA ratios were found in all analyzed species. The lower values of the lipid nutritional quality indices (AI &lt; 1, TI &lt; 1) and higher for h/H index (0.8–1.78 for fish and 1.52 to 4.67 for bivalves and shrimp) confirm that the commonly consumed Black Sea fish and shellfish may provide health benefits for local populations. This study shows the seafood amounts that can provide the minimum recommended intake of omega-3 polyunsaturated fatty acids