Abstract

The effect of a previous combined treatment (CO2-enriched modified atmosphere packaging, MAP and high-pressure processing, HPP, 150 MPa/5 min) on lipid stability of refrigerated (10 days/4 degrees C) salmon (Oncorhynchus kisutch) was studied. The following processing conditions were compared: B-0 (fish without MAP or HPP), B-1 (fish packaged under MAP and without HPP), B-2 (fish subjected to HPP without MAP) and B-3 (fish subjected to MAP and HPP). An inhibitory effect (P < 0.05) on lipid hydrolysis and oxidation was obtained by the presence of CO2 in the packaging medium; values detected at day 10 for B-0 and B-1 fish were 80.72 and 49.61 (g free fatty acids, FFA, kg(-1) lipids), 6.14 and 2.81 (meq active oxygen kg(-1) lipids; peroxide value), 5.05 and 3.10 (mg malondialdehyde kg(-1) muscle), and 5.56 and 2.70 (fluorescence ratio), respectively. Furthermore, inhibition of lipid damage was observed for HPP alone; values detected at day 10 for B-2 fish were 76.24 (g FFA kg(-1) lipids) and 5.28 (meq active oxygen kg(-1) lipids). The lowest average values for lipid hydrolysis and oxidation were obtained in samples corresponding to the combined treatment (B-3 batch), differences being significant (P < 0.05) at day 10 for FFA (41.43 g kg(-1) lipids), peroxide (1.84 meq kg(-1) lipids) and fluorescence (2.50) values.