Effects of cooking on textural properties on meagre (Argyrosomus regius) fillets from two different methods of rearing (tanks and cages)

Texture is an important attribute of fish. Producers and consumers are interested in fish texture because it influences fish processing and sensorial profile. Cooking can markedly modify texture by inducing collagen gelatinization, myofibrillar proteins denaturation, water losses and fat drippings. The aim of the current work was to describe the effects of cooking on textural properties of farmed meagre (Argyrosomus regius) from two different rearing systems: tanks and seawater cages. Fish were sampled in May and July from tanks (n=36) at constant temperature (about 20°C) and from seawater cage (n=36) in the farm “Il Vigneto” (Grosseto, Italy). Left and right fillets were analyzed raw and steam cooked after cooling, respectively. Textural measurements were taken with a texturometer equipped with a 200 N load cell, performing one cycle compression test on epaxial, ventral and caudal part and one cycle shear blade test on the central part. Data were analysed by PROC GLM procedure including weight, methods of rearing, sampling date, day of storage and the interaction (methods of rearing x day of storage) in the model. Fish from tank and cage weighted 1009 vs 902 g (P<0.05), respectively. Cooked fillets compression test values from tank and cage differed significantly (P<0.01): 4.10 vs 2.90 N, 3.10 vs 2.60 N and 2.97 vs 2.20 N in epaxial, ventral and caudal part, respectively. No significant differences resulted in shear test. Both raw and cooked fillets from tank showed a higher compression force applied than those from cage and it could be explained by constant temperature of tank that generally makes fillets harder by increasing number and thinness of muscle fibres. The greater hardness values from tank were not nullified by cooking. Further analysis should be performed to investigate the relationship between rearing method and muscle development.