CHANGES IN PROXIMATE COMPOSITION OF THORNBACK RAY (RAJA CLAVATA, L. 1758) SURIMI DURING WASHING AND FROZEN STORAGE

Abstract

The effects of frozen storage of surimi produced from thornback ray and the washing of mince on the chemical composition were investigated. The crude ash content which was initially found as 1.38% in raw thornback ray decreased approximately 12 and 80% after the first and second washing, respectively. After the third washing, crude ash content increased to 207% of the amount in the second washing because of addition of salt to the last washing water. The crude protein content of mince also decreased approximately to 28 and 20% after the first and second washing, respectively. After the third washing, the decrease in the lipid levels was approximately 30%. At the end of 6 months of frozen storage at−23.8 ± 2C, dry matter, crude ash and crude protein contents increased in a greater ratio in surimi containing 4% sorbitol, 4% sucrose and 0.3% Na-tripolyphosphate than surimi prepared with 8% sorbitol and 0.3% Na-tripolyphosphate. PRACTICAL APPLICATIONS In the present study, the effects of frozen storage of surimi produced from thornback ray and the washing of mince on the chemical composition were investigated. Washing procedure significantly decreased crude ash, crude protein and crude fat content of mince. There were significant differences in moisture, crude ash, and crude protein contents during the 6 months storage period of frozen surimi obtained by using different cryoprotectant mixtures. The folding test scores were highest in fresh surimi and during the first two months of storage. Thornback ray can be used for the production of surimi.