Quality characteristics of farmed Atlantic salmon (Salmo salar) fed diets high in soybean or fish oil as affected by cold-smoking temperature

Abstract

Effects of cold-smoking temperature (range 21.5–29.9°C) and dietary oil sources (pure Peruvian fish oil, FO, or pure soybean oil, SO, supplements) on physical and chemical quality characteristics were determined in Atlantic salmon (Salmo salar). Weak but statistically significant relationships were found between texture, composition, liquid holding capacity, colour parameters and yield, and cold-smoking temperature. Coefficients of determination (R2) ranged from 0.01 to 0.48. Colorimetric parameters were largely unaffected by temperature. Total phenol content exhibited the strongest positive linear correlation with temperature (P<0.01). Liquid holding capacities were reduced by increasing temperatures, but significantly only for salmon fed the FO diet (P=0.055 for salmon fed the SO diets). Liquid loss during storage was not affected by prior processing temperature, but were significantly higher in salmon fed the SO diet. Increased temperature caused decreased processing yield and water loss and increased fat loss during vacuum storage, and firmer fillet texture. A significant (P<0.05) reduction in processing yield (1–2g/100g) was found at the highest temperatures. The fish fed the SO diets had a lower carotenoid content and redness (a*-value) than salmon fed the FO diet (P<0.05). Liquid holding capacity was lower in salmon fed the SO than the FO diets (P<0.05) possibly as a result of the different fatty acid composition of the fillets. The effects of cold-smoking temperature and dietary oil source on quality were in general low to moderate, and indicate that salmon represents a fairly robust raw material for cold-smoke processing.