Two farmed fish species of great importance in the European market, gilthead seabream ( Sparus aurata; GSB) and seabass ( Dicentrarchus labrax; SB) reared in different conditions were analysed to determine the best index to be used for calibration of a prototype designed for rapid measurement of freshness in ice stored fish. Sensory evaluation (quality index) was related to K-value (percent of the ratio of inosine plus hypoxanthine to adenosine-5-triphosphate (ATP) and breakdown products) and Torrymeter readings, chosen as indices that detect early changes in the ice stored fish. Higher K-values were obtained in SB than in GSB, however the degradation of ATP and derivatives followed the same pattern in the different lots in each species. No statistical differences in the evolution of K-value for the same storage time were observed, irrespective of the amount of ATP and breakdown products, muscle composition and rearing conditions of the fish. K-value correlated strongly with storage time and sensory evaluation measured in the raw fish, however, correlation of Torrymeter readings with storage time or sensory evaluation was much lower. This makes K-value a good index in these species for calibrating an apparatus designed to measure time-related changes in fish in response to chill storage.
Lipid hydrolysis and oxidation in farmed gilthead seabream (Sparus aurata) slaughtered and chilled under different icing conditions