Preliminary results on quality and quality changes in reared meagre (Argyrosomus regius): body and fillet traits and freshness changes in refrigerated commercial-size fish

摘要

Meagre (Argyrosomus regius) intensively reared in tank by a Tuscany farm and fed commercial diets, were examined to study a) marketable and flesh nutritional traits in commercial-size fish and b) loss of freshness under refrigerated storage condition. Eighty fish, sampled in May, July and November (at 24, 26, 30 months of age) were submitted to linear measurements and weight of the most important body components. Whole fillets were analysed for moisture, lipid and fatty acid composition. Data were analysed by ANOVA (sampling date). A sub sample of fifty-four meagre (902-1840 g b.w.) was stored at 1 degreesC with ice cover and evaluated every 24 h after death until spoilage for the EU freshness classes, dielectric properties, rigor index, muscular and eye liquor pH, K-1% freshness index. Data were analysed by regression on time after death. A small sample of meagre (n = 6) and sea bass (Dicentrarchus labrax) (n = 6), reared in analogous rearing condition in the same farm were compared by ANCOVA on body weight (average b.w. 668 g). Meagre were characterised by 1.04 condition factor, 44% fillets, 6% viscera, negligible mesenteric fat (congruent to1%) and 94.5% dressing yield. The head incidence increased (P < 0.01) with b.w. increase. Moisture increased while lipid decreased (P < 0.01) in fillet from July to November (74.47 vs 75.96%; 2.93 vs 2.06%). An index of thrombogenicity calculated from the quantitative fatty acid composition was very low (0.10). In comparison with sea bass of the same body weight, meagre had greater length (41.2 vs 37.6 cm), head incidence (29.9 vs 20.7%) and dressing (94.8 vs 89.2%) and lower viscera (5.2 vs 10.9%), mesenteric fat (0.9 vs 7.9%) and intramuscular fat (2.24 vs 12.78%) incidences. Meagre had a 9-day shelf-life (E class from 1(st) to 3(rd) d and A class from 4(th) to 7(th) d). Rigor index and impedance remained higher than 90% and 66, respectively until the 3(rd) d after death. The quality traits found for this species indicated meagre as a promising candidate for Mediterranean aquaculture.