Authors: HARTMUT REHBEIN, ŞÜKRAN ÇAKLI
Abstract: Frozen-thawed fish and fillets are being marketed as fresh fish fillets. One of the methods which helps us to differentiate unfrozen from frozen-thawed fish fillet is the enzymatic method. By means of the freezing and thawing process lysosomal enzymes are released. Lysosomal enzyme activities have the enzymes which decompose protein, carbohydrate, fat and nucleic acids. In this research, fresh, stored in ice, frozen and smoked salmon fish (Onchorhyncus ketaand Salmo salar) have been used. In press juice and in extracts of these fish a muscle lysosomal enzyme \alpha-Glucosidase (E.C. 126.96.36.199) in activitation quantities was detected. The lysosomal enzyme activities of the press juice of frozen-thawed salmon fish fillets were observed to be higher thanthose of fresh salmon fish fillets. The \alpha -Glucosidase activity (\DeltaE 405 x10 -2 h -1 x mg protein) was detected as 0.151 (at the beginning) in fresh fillets of salmon fish and that value of the salmon fish which are stored in ice was observed to have increased to 0.309 by the 9th day. The activity in frozen-thawed fillets was detected as 1.185 to 1.503. The a-Glucosidase activity of smoked salmon with different storage expiry periods was observed to be 0.969-4.51. At the end of the research it can be said that the lisosomal enzyme \alpha -Glucosidase (E.C. 188.8.131.52) can be used to differentiate between processed, nonprocessed, fresh and frozen-thawed fish and fillets.
Keywords: Lysosomal Enzyme Activite, a-Glucosidase, Salmon, Onchorhyncus keta, Salmo salar.
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