SDS-PAGE CHANGES OF RAW, SMOKED AND MARINATED RAINBOW TROUT (Oncorhynchus mykiss) DURING FROZEN STORAGE

This study aimed to determine the effects on protein of frozen storage time (-20 degrees C), and on properties of raw, marinated and smoked rainbow trouts (Oncorhynchus mykiss). Therefore, the fish were smoked and marinated. All filleted fish samples including also the raw ones were vacuum-packed, subjected to 9 months of frozen storage and analyzed at 1-month intervals. Changes in muscle proteins of raw, smoked and marinated trout samples (Oncorhynchus mykiss) have been examined using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). SDS-PAGE and densitometric analysis revealed that intensity and the number of protein bands were not changed until the 9th month of raw and marinating process while the bands of some protein patterns denaturated when trout muscle was subjected to 9 months of smoking process. Myosin heavy chain (MHC) band with molecular weights of 205 kDa and actin band with molecular weights of 45 kDa appeared during 9 months of raw, smoking and marinating process. Similarly, other main myofibrillar proteins, tropomyosin (37.7 kDa), troponin-T (32.9 kDa), myosin light chain 1 (27.2 kDa), and myosin light chain 2 (20.4 kDa) also did not show any differences during 9-months storage. Subsequently, there were significant monthly changes in the protein percentages caused by smoking and marinating processes excluding the raw ones (P<0.01).