Differences in chemical, physical and sensory properties during shelf life assessment of wild and farmed gilthead sea bream (Sparus aurata, L.)

Abstract

The aim of this study was to determine and compare differences in physical, chemical and sensory post-mortem changes between wild (W) and farmed (F) gilthead sea bream (Sparus aurata). Ungutted fish were stored in ice from harvesting up to 20 days and freshness indicators were analyzed at regular intervals. Proximate composition of the samples differed in lipid (W = 0.86 ± 0.12 ; F = 4.18 ± 0.16) and moisture content (W = 79.12 ± 0.48 ; F = 74.50 ± 0.82). Data from sensory evaluation were described using linear regression models. Sensory schemes for cooked and raw fish were found to be suitable in establishing specific attribute deterioration and shelf life duration (W = 14 days ; F = 17 days). Changes in pH and dielectric properties were influenced by differences in lipid content, while changes in total volatile base nitrogen and trimethylamine showed high correlation with sensory assessment and storage time, but stayed below the acceptance limit for human consumption (W : 24.47 mg TVB-N ⁄ 100 g and 4.14 mg TMA-N ⁄ 100 g ; F : 26.18 mg TVB-N ⁄ 100 g and 3.84 mg TMA-N ⁄ 100 g), and thus were notreliable indicators of quality changes during storage in ice. Deterioration of flesh lipids, assessed by thiobarbituric acid index, differed between the samples, but presented no serious problem during storage time. In order to determine the importance of individual results, all obtained data were submitted to principal component analysis. Variations in sensory, physical and chemical assessment were described by PC1 (storage time) ; variations in lipid and moisture content were described by PC2 (capture grounds). A clear separation of the investigated samples, according to the storage time and capture grounds, was observed.