Effect of immersion ohmic heating on thawing rate and properties of frozen tuna fish.

In the present study, the application of immersion ohmic heating was examined to improve thawing of frozen tuna fish cubes. The experimental tuna cubes (3 × 3 × 3 cm) were thawed under ohmic heating subjected to three different voltages (40, 50, and 60 V) with three different concentrations (0.3, 0.4, and 0.5% w/v) of brine solution. The parameters associated with the quality of tuna, such as thawing time, thawing rate, thawing loss, cooking and total losses, centrifugal loss, lipid oxidation, texture, and color, were investigated during ohmic heating thawing, and compared with the conventional still air thawing, water thawing at 27 and 40 ℃. The results showed that immersion ohmic thawing significantly decreased the thawing time of frozen tuna fish cubes. Thawing time in ohmic treatment (50 V- 0.3% brine) was 5.95 times shorter than conventional conditions. The lowest thawing and cooking losses were observed at ohmic treatments. In addition, the ohmic treatments (group 1) were evaluated versus conventional methods (group 2) and the results showed that thawing and total losses in group 1 were significantly lower than group 2.