Abstract: NaCl and CaCl2 solutions at different concentrations were used to thaw frozen tuna pieces. In order to explore the effects of the thawing methods on tuna quality, the thawing time, color difference, salt soluble protein content and texture were analyzed, and the microstructure of tuna meat after thawing was observed. The results showed that with the increase of salt concentration, the thawing rate and salt infiltration rate increased gradually for each salt. Tuna thawed in 3% CaCl2 had good water retention, desired salt-soluble protein content and texture, and its microstructure was best maintained. To sum up, thawing in 3% CaCl2 had a reduced effect on the quality and could maintain better freshness of tuna.

Key words: tuna, thawing in salt solutions, salt soluble protein, salt infiltration, microstructure