Appraising the Shelf Life of Farmed Cobia, Rachycentron canadum, by Application of a Quality Index Method

Abstract

Freshness is the main concern of seafood quality, and the principal method to evaluate seafood freshness is sensory evaluation. The aim of this work was to study the quality changes of cobia, Rachycentron canadum, under ice storage through sensory and physical analysis as well as bacterial counting of specific spoilage organisms (SSOs). In particular, the utilization of a quality index method (QIM) scheme was proposed. Samples stored for 0–30 d were analyzed with the QIM. Ten panelists observed and registered the changes occurring in the fish starting on day zero and ending when the fish were spoiled. After developing the scheme, 11 sensory attributes were described in 23 points, which detailed the appearance of skin, eyes, abdomen, gills, and flesh deterioration. The volatile nitrogen compound measurements and microbiological data of the SSOs determined a shelf‐life of 19 d for the samples. Sensory analysis showed a rejection point at 15.67 d of ice storage. The natural degradation of myofibrillar proteins and collagen was observed during ice storage. In conclusion, a shelf‐life of 15 d was defined for raw cobia stored on ice.

Development of a quality index scheme and shelf-life study for whole tambaqui (Colossoma macropomum)

“…The gradual increase in pH values after harvesting also reflected the production of alkaline bacterial metabolites in spoiling fish and coincided with the increase in total volatile basic nitrogen (Abbas et al 2008). Similar results were reported for tambatinga, whith a linear increase in pH from 6.25 to 6.74 at day 28 , and for eviscerated tambaqui, whith an increase in pH from 6.01 (first day) to 6.45 at the end of shelf-life (22 th day) (Araujo et al 2016). The Industrial Inspection and Sanitary Regulation of Animal Products -RIISPOA (Brasil 2001) establishes that the maximum pH for fresh fish should be below 6.8 in external meat and 6.5 in the inner flesh (Cartonilho and Jesus 2011).…”

“…The QI scheme in this study had four quality attributes divided into 12 parameters and 29 demerit points, which was almost 20% lower than that developed for eviscerated tambaqui (36 demerit points) (Araujo et al 2016). However, similar results were obtained for pacu, Piaractus mesopotamicus, with 16 parameters and 32 demerit points (Borges et al 2013) and for the hybrid tambacu (C. macropomum and P. mesopotamicus), with 11 parameters and 26 demerit points (Borges et al 2014a).…”

“…Thus, proteases and microorganisms cause natural degradation of myofibrillar proteins and collagen and explain how the muscle becomes weak during ice storage (Ando et al 1999). The collagen degradation of muscle fibers of cobia (Rachycentron canadum) was as certained by sensory and histological analyses (Fogaça et al 2016). After death, collagen was degraded through a progressive breakdown of the collagen junctions between the myocommata and the muscle fibers caused by microbial and enzyme reactions that are promoted by pH increases (Huss 1997).…”

“…Therefore, skin mucus and odor, as well as general appearance and ventral elasticity had the highest importance for tambaqui QI. For eviscerated tambaqui all the quality attributes, except for blood press eyes, were relevant for the QI scheme (Araujo et al 2016).…”

Freshness Assessment and Shelf-Life Prediction for Seriola dumerili from Aquaculture Based on the Quality Index Method

“…QIM methodologies are being widely applied to various fish species [36,37,38,39] and products [40,41], reflecting the importance of the methodology for fish freshness evaluation and shelf-life prediction. Besides the expected differences between different species, it is also possible to obtain variations in the values of the evaluation parameters for the same fish species, mainly due to storage conditions or type of product [42,43,44,45], reflecting the expected variance that other methods do not incorporate (i.e., EU scheme).…”