Optimization of salt water-cold storage combined thawing technology of big-eye tuna chunk

In order to ensure the quality of big-eye tuna chunk after thawing, salt-water thawing and refrigerated thawing methods were combined to defrost the big-eye tuna chunk from deep freezing. Physicochemical sensory and E-nose analysis were used to evaluate the thawing technology, and get the optimal thawing process. Texture and color were assessed to investigate the major factor which affects the tuna meat quality, including the salt content, salt-water temperature and immersion time. The thawing process was optimized by the means of L9 (34) orthogonal test. The optimized result was 40℃ salt-water temperature, 3.0 % salt content and 90 s immersion time. Under the optimization condition, the equal temperature time was 12 h, and the tuna chunk had 26.27 a* value, 570.05 chewiness and 7.20 sensory scores, with the microbial index was under the industry standard. E-nose analysis showed the salt content has a significant effect on the odor of tuna chunk. Comparison with common thawing methods of tuna chunk, this combined thawing technology shows obvious advantage.