Textural, colour and proximate composition changes induced by cooking in fillets of meagre during the first days of storage.

Meagre (Argyrosomus regius), a teleost fish spread in the Mediterranean sea, in the Black sea, in the Atlantic Europe and in the West African coast, has excellent biological attributes for aquaculture: good feed conversion ratio, high growth and high fertility rates and withstands tank captivity. It adapts to different environments and it doesn’t show significant pathologies. Then meagre is one of the new emerging species promoted for Mediterranean aquaculture with the purpose of differentiating fish production and expanding farmed fish supply in the European market. Aim of this research was to analyze raw and cooked fillets composition and quality of meagre during refrigerated (1 °C) storage for 3 days (1st, 2nd, 3rd; n. 6 fish per day). The fish, reared in a farm near Ansedonia (Grosseto-Italy) and fed a commercial diet (51.6% of crude protein and 19.3% of lipids, on dry matter basis), were sampled in January (n. 18) and in March 2010 (n. 18). Morphological indexes and marketable parameters were determined (total weight: 850.6±178.8 g, condition factor: 1.12±0.1, dressed yield: 96.4±0.7%, fillets yield: 50.9±3.5%, cooked fillets yield: 94.3±6.0%). L*a*b* colour, texture and proximate composition (moisture, ash, protein, ether extract, total lipids) were analyzed on raw (left) and cooked (right) fillet of each fish. The cooking was performed in boiling water to a core temperature of 65 °C for 10 minutes, wrapping each fillet in an aluminum foil. Sampling date influenced colour parameters: fillet lightness (L*) resulted 53.7 and 48.6 in the epaxial muscle, 57.9 and 51.9 in the caudal region, in the 1st and in the 2nd sampling, respectively. Higher total lipids content observed in the 2nd sampling (3.01 vs 2.72%, p<0.001) could be explained by the slightly increased fish weight (879.6 vs 821.7 g). Colour parameters significantly changed during the storage, showing a different behavior in each location of the fillet (epaxial, ipaxial, caudal) where the measurements were performed. No changes in texture were observed in relation to the sampling date or the storage days. The fillets cooking produced a marked increase of b* (about 14 units) and L* values (+30-40%) and a decrease of moisture (75.4 vs 72.6%, p< 0.001), significantly modifying the protein (from 20.6 to 23.4%) and total lipids content (from 2.77 to 2.96%, p< 0.01). The changes induced by the cooking process on the fillets previously stored for several days could give useful information about their quality involution linked to the freshness losses in this species interesting for Mediterranean aquaculture.