Quality outline of European sea bass (Dicentrarchus labrax) reared in Italy:: shelf life, edible yield, nutritional and dietetic traits

The final product quality of European sea bass was outlined through some results on (1) quality traits in a large range of body size (80-1580 g weight) and (2) changes in sensorial and objective quality parameters during shelf life, as influenced by the rearing system, storage and stress. More than 500 European sea bass of commercial size were used in several trials. All fish were subjected to linear and weight measurements. In most trials, sea bass were stored at 4 or 1 degreesC with ice cover and evaluated every 24 h after death until spoilage for the EU freshness classes and for a large number of physical and chemical quality traits (rigor index, dielectric proper-ties, muscle and eye liquor pH, water-holding capacity (WHC), water, protein, ash, total, neutral and polar lipids, cholesterol, fatty acids, malonaldehyde, adenine nucleotides and biogenic amines). Fillets showed on the average isometric growth, but the dorsal muscle grew faster and the ventral one slower than the body weight. A moderate corpulence increase in fish shape during growth emerged. The size range from 500 to 940 g-when incidences of fillets and dorsal muscle were higher than 48% and 31% and that of viscera was lower than 10%-can be suggested for having sea bass with the better edible portion yield. Protein and ash contents of muscle remained constant with body weight increase, while moisture and cholesterol content decreased; total lipid moderately increased along with the triglyceride incidence. On the whole, the muscular fatty acid pattern determined good indexes of atherogenicity (IA) and mostly of thrombogenicity (IT). Sea bass stored at 4 or 1 degreesC with ice cover had a 6- and 10-day shelf life, respectively. In the first 2 and 3 days, respectively, sea bass were Extra (always with 100% rigor index) and had Fish Tester values decreasing to 64 or 73, respectively, and negligible levels of malonaldehyde (MDA) and biogenic amines. In the following 2 and 3 days, respectively, sea bass became A fish (good quality), with decrease of rigor index (IR) and Fish Tester (FT) and slight increase in malonaldehyde and putrescine contents. In the following 2 and 4 days, respectively, sea bass became B fish (bad quality), with further decrease of rigor index and Fish Tester and moderate increase of malonaldehyde and putrescine. Thereafter, fish were unfit for human consumption. No difference in quality parameter of fish reared in aerated (4.3 ppm O(2)) or hyperoxic (9.3 ppm) conditions was found. Stress shortened the pre- and post-rigor phase and shelf life. (C) 2001 Elsevier Science B.V. All rights reserved.