Development of different damage pathways in Norway lobster (Nephrops norvegicus) stored under different chilling systems

Abstract

Slurry ice is a biphasic system that has recently shown a number of advantages when employed as a chilling medium for fish species. Its use for a crustacean species of high commercial value, Norway lobster (Nephrops norvegicus), was evaluated in parallel with traditional flake icing. Quality parameters related to microbial spoilage and biochemical breakdown (aerobe and psychrotroph counts, pH, K value, total volatile amines, trimethylamine, free fatty acids and non-enzymatic browning reactions) were assessed and compared with sensory (carapace, eyes, gills, odour and flesh) acceptability. Storage in slurry ice produced a significant (P < 0.05) inhibitory effect on both microbial growth (as determined by aerobes, psychrotrophs and volatile amines) and autolysis breakdown (as determined by K values and the release of free fatty acids) in comparison with the flake ice batch. In contrast, an enhancement effect of slurry ice on carapace browning was observed as a result of enzymatic browning development. Slurry ice batch also showed a more intense non-enzymatic browning reaction in the lipid extract of the edible flesh. With a view to limiting both browning effects, the incorporation of an anti-melanosis agent in the liquid phase of the slurry ice system is envisaged.