Effect of high pressure treatment on the quality of rainbow trout (Oncorhynchus mykiss) and mahi mahi (Coryphaena hippurus)

High pressure processing (HPP) is becoming a promising seafood preservation method. The objective was to investigate the effect of HP on quality of rainbow trout and mahi mahi during cold storage. Skinless fillets treated with different pressures (150,300,450,and 600MPa for 15 min) and stored at 4 degrees C were analyzed 1,3,and 6d storage. Red muscle was analyzed for lipid oxidation products by measuring thiobarbituric reactive substances (TBARS) and whole muscle was analyzed for total aerobic count, texture profile analysis, and color. A pressure of 300Mpa effectively inactivated the initial microbial population in rainbow trout (6-log reduction). However, inactivation of the initial population on mahi mahi was only about 4-log reduction at the same pressure. Microbial growth was significantly related after HPP. Color results showed that redness (a* value) of rainbow trout at 300MPa and above was significantly (P<0.005) lower compared to mahi mahi. TBARS values for rainbow trout increased with increased pressure, where as the same trend was not seen for mahi mahi where maximum oxidation was found at 300MPa and then declined. This study demonstrates the usefulness of HPP in seafood processing and the influence of species variation on processing parameters. The optimum HPP conditions for influencing lipid oxidation, microbial load, and color changes were found to be 300MPa for rainbow trout 450MPa for mahi mahi.