Quality assessment and shelf life of narrow-barred Spanish mackerel ( Scomberomorus commerson) and Javelin grunter (Pomadasys kaakan) fillets during refrigerated storage

In the present study, changes in the quality indices and shelf life of fresh fillets of narrow-barred Spanish mackerel (Scomberomorus commerson) and Javelin grunter (Pomadasys kaakan) were investigated over a 12-day storage period in the refrigerator using sensory, chemical (pH, TVB-N, PV, TBARS), and microbiological (mesophilic and psychrotrophic bacterial counts) indices. The sensory scores of both fish fillets reached less than 4 (the acceptable limit for consumer acceptance) on the sixth and eighth days of storage, respectively. The mesophilic and psychrotrophic bacterial counts in the fillets of both fish increased with an increase in storage days, although the rate of increase was different between the two groups, and psychrotrophic bacteria increased to a greater extent with an increase in storage days. The pH of the fresh mackerel and grunter fillets decreased from 6.52 and 6.24, respectively, at the beginning of the storage period to 7.49 and 7.25, respectively, on the final day of storage. The TVB-N level in both fish increased with an increase in storage days and reached 28.36 mg N/100g in mackerel and 36.25 mg N/100g in grunter on the twelfth day of storage. The lipid oxidation indices, namely PV and TBARS, in the fillets of both fish were significantly higher at the end of the storage period than at the beginning. The results of sensory, microbiological, and chemical indices showed that the maximum shelf life of narrow-barred Spanish mackerel and Javelin grunter fillets is 6 and 8 days, respectively.