Postmortem Changes in Quality Indices of Ice-Stored Flounder (Paralichthys Patagonicus)

Abstract

The characteristics of flounder (Paralichthys patagonicus) were evaluated during a 12‐day period of storage in ice by monitoring the biochemical, microbiological and sensory parameters. The adenosine‐5′‐triphosphate and adenosine‐5′‐diphosphate were not detected, and the initial content of adenosine‐5′‐monophosphate (AMP) rapidly decreased to zero. Inosine‐5′‐monophosphate (IMP) but not adenosine (Ado) was present in muscle extracts. The AMP deaminase activity was found in the muscle. Conversely, the Ado deaminase activity was not detected. A 55% decrease in IMP concentration occurred during the first 2 days of storage. The inosine content was barely detectable (<0.1 μmol/g), probably because of the high nucleoside phosphorylase activity in the muscle. Hypoxanthine significantly (P < 0.01) increased up to the seventh day and then remained approximately constant. The muscle pH fluctuated between 6.6 and 7.0. The iced flounder was microbiologically acceptable for up to 7 days with aerobic plate counts reaching <107 cfu/g. The sensory score, determined by the Quality Index Method, linearly increased (r2 = 0.96) with the keeping time. All the parameters, including the K‐value, indicated that the shelf life of iced flounder was 7 days.

Bacterial Diversity and Changes towards Spoilage Microflora of Iced Alaska Pink Salmon

“…The occurrence of P. fluorescens and P. putida increased with a corresponding decrease in the variety of bacterial species present during storage. The predominance of these organisms can be attributed to the ability of Pseudomonas to grow rapidly at chill temperature [35] and suppressed growth of other bacteria [36,37]. The importance of Pseudomonas spp.…”

Postmortem changes in physicochemical properties of songpu mirror carp (Cyprinus carpio) during iced storage

“…The pH value of fish products after being caught is found between values 6.7 and 7.5. Variations among the initial pH values may be due to the species, seasons, and diet, level of activity or stress during the catch as well as type of muscle (Massa, Palacios, Paredi, & Crupkin, 2005). It can be noticed that pH showed a decline to 7.0070.17 at 8 h with regard to the storage time, and then increased to 7.2670.10 at the end.…”

Characterization of proteases isolated from Kudoa septempunctata

“…Following death of the fish, the stored carbohydrate glycogen is anaerobically degraded and lactic acid is accumulated in muscle resulting in a pH drop from 7.4 to 6.0 [2]. In addition, previous studies have reported that the pH of muscle in post-mortem flounder and halibut decreases to pH 6.5 for 3 days [6,16]. Therefore, we suggest that K. septempunctata does not cause post-mortem myoliquefaction based on the relationship between the optimal pH of the parasite cysteine protease and the pH of muscle in post-mortem fish.…”