Atlantic salmon (Salmo salar, L.) as raw material for the smoking industry. I: effect of different salting methods on the oxidation of lipids

Abstract

The changes in total fat content, fatty acid composition, tocopherol, ascorbic acid, pH and oxidation were analysed in response to different salting methods, either dry or brine, in cold-smoked (20 or 30 °C) Atlantic salmon (Salmo salar, L.). The fish were lean ocean-ranched salmon caught at Iceland in June 1998 and farmed Norwegian salmon slaughtered in November 1998 and April 1999, differing in fresh fillet fat content from 84 to 169 g kg⁻¹ wet weight. The total fat content decreased in all groups during processing, whereas the relative fatty acid composition of the fillets was not severely affected during salting and cold-smoking. The most conspicuous process consumption of antioxidants in all the groups was the relative ascorbic acid loss (58–82%). Generally, no clear effect of different salting methods was observed on the tocopherol loss during processing, but brine salting had a stronger effect on both fat and ascorbic acid loss than dry salting. The fattiest fish showed the highest oxidation during processing and they lost more tocopherol, but the final oxidation levels were generally low (thiobarbituric acid reactive substances, TBARS: 6.0–14.7 μmol kg⁻¹), reflecting the antioxidative protection offered by the vitamins during processing.