Postgraduate of Kyiv National University of Trade and Economics
BIOLOGICAL VALUE OF DOGFISH PROTEIN
Background. Fish industry of Ukraine set the task to increase production volumes and reduce import dependancy of the consumer market. Black Sea dogfish is valuable raw materials for the domestic market of fish goods, its safe usage in food was set by the complex of the studies .
According to PivdenNIRO stocks of spiny dogfish sharks in the Black Sea and the Azov Sea in 2015 amounted to 1.232 tons. The volume of extracting spiny dogfish shark was only 3 tons in 2015, which is 147 % more than in 2014 year, but not enough in terms of efficiency of food use .
Accordingly, systematic monitoring of capabilities of different types of food using water biological resources, promising areas of recycling to provide population with biologically valuable fisheries products is a relevant task.
The aim is the research of biological value of proteins of the Black Sea dogfish that is an important criterion for evaluation of her nutrition value in general for the purpose of grounding the feasibility of use in the domestic food industry.
Material and methods. The object of the study were female katran dogfish mature individuals with average weight of 10.25±0.55 kg, caught in the Black Sea near Zmiinyi Island in the autumn – winter period (November-February). Sampling for researches was carried out according to GOST 7631–2008 . Method of an ion-exchange liquid and columnar chromatography was applied to determine amino-acid content of the Black Sea spiny dogfish shark. Registration of amino acids was carried out by a detection method with ninhydrin on the automatic analyzer T 339 (Czech Republic). The quality and quantitative composition of amino acids was determined comparing chromatograms of the standard and researched mix of amino acids [11; 12].
Objective assessment of biological value of proteins was determined by a complex of indicators: amino-acid score, KRAS, utility coefficient. Amino-acid score of proteins of food fishes was determined according to a scale of FAO / WHO.
Results. It has been proved that sharks protein is valuable and contains a set of essential amino acids.
Glutamic and aspartic acid, arginine, alanine and serine dominate among the amino-acids. The quantitative content of asparagine acid is less than contents of dominating glutamic one 2.13 times, the arginine is 2.37 times less, alanine – 2.64 times, sarin – 3.52 times. The sum of essential amino acids in muscular tissue of dogfish was 5.781 ± 0.257 mg on 100 g of a sample, and essential amino acids – 8.165 ± 0.361 mg on 100 g of a sample. The relation of quantity of essential to nonessential amino acids for samples makes 0.75.
Indicators of KRAS of proteins of dogfish and a herring Atlantic are characterized low by values (43.3 and 44.9 %) compared to a mackerel (47.3 %) that indicates balance of essential amino acids.
Conclusion. The studies indicate a high biological value of protein of spiny dogfish sharks compared to other types of commercial fish. For a set of indicators of biological value of protein it’s recommended to use spiny dogfish shark meat in food technology to saturate domestic market with healthy food based on domestic fish.
Keywords: amino-acid structure, spiny dogfish shark, amino-acid score, native proteins, biological value.