HARVESTING, HANDLING PRACTICES AND PROCESSING OF BLUEFIN TUNA CAPTURED IN THE TRAP FISHERY: POSSIBLE EFFECTS ON THE FLESH QUALITY

SUMMARY We investigated the physiological responses of bluefin tuna under stress and stress-free state conditions to assess the possible effect on color variability in muscle tissue. The study was carried out in the trap fishery of Sardinia (western Mediterranean). Here bluefin tuna pass from the wild to conditions of captivity and are then fished out during the “mattanza” and prepared for fresh and cannery markets. We investigated plasma lactate, cortisol and glucose and the color variability of flesh by the RGB color space model. The experiment provides a comparison of stressors and monochromatic channels Before vs. After the stress state. Results showed a significant accumulation of stressors from Before to After. The colorimetric analysis highlighted that this accumulation did not affect the color variability of flesh. Fresh samples showed significant differences for Rp, Gp and Bp over time (P < 0.05), whereas no differences were found in frozen samples. We suggest that the adoption of good fishing practise and handling of tunas is an expedient strategy to obtain the maximum quality of product and highest market quotation. RESUME

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