Quality evaluation of living and postmortem Chinese mitten crabs (Eriocheir sinensis)

Abstract

Total volatile basic nitrogen (TVBN), biogenic amine, total viable count (TVC), volatile compounds, and sensory evaluation were conducted to assess the quality of Chinese Mitten Crabs (Eriocheir sinensis) at living, zero, 2, 5, 10, 15, and 24 hr postmortem. The sensory evaluation found a noticeable odor of spoilage becoming evident 10 hr postmortem. The TVBN value increased and then decreased as time increased, reaching 23.67 mg N/100 g at 24 hr postmortem. Although biogenic amines were detected at 5 hr postmortem, by 24 hr postmortem these had not reached dangerous levels of toxicity. The initial TVC (6.06 Log CFU/g) of the living crab samples was relatively high and climbed further postmortem, reaching 10.00 Log CFU/g 24 hr postmortem. Trimethylamine was detected in the living sample in belly meat and 2 hr postmortem in crab roe and reached 8.33 µg/g in the roe 24 hr postmortem. Indole was detected at 0 hr (belly meat) and 10 hr (crab roe) postmortem, but did not change significantly during the observation period. Sulfur‐containing compounds were detected 5 hr after death and gradually increased over the observation period. Most indicators showed major changes at 5 hr and 10 hr postmortem. By 10 hr postmortem, the crab had entered the putrefaction stage and was thus no longer safe for consumption.

Physicochemical and microbiological changes in postmortem crayfish (Procambarus clarkii) stored at 4 °C and 25 °C

“…Putrescine and cadaverine were the major BAs in tail meat of samples at 25°C, and increased significantly ( p < 0.05) during postmortem storage, which reached 28.18 mg kg −1 and 187.32 mg kg −1 , respectively, after 12 h of storage, and cadaverine increased faster than putrescine. The BAs contents of aquatic product might be related to the activities of decarboxylating enzymes and the content of free amino acids, which were the precursors of BAs (Wang et al ., 2020b). Additionally, lower temperature could inhibit the amino acid decarboxylase activity of microorganisms, which consequently inhibited the production of BAs.…”

Survival and Metabolic Modulation of Swimming Crab Portunus trituberculatus During Live Transport

“…Freshness plays a crucial role in crab quality, reducing rapidly after crab death (Wang et al, 2018). In the present study, 80% of the crabs kept in the transport bag were able to survive for 24 h, which is considerably longer than those under air exposure even at the optimal temperature (10 • C; <12 h) (Lu et al, 2015(Lu et al, , 2016Dong et al, 2019).…”

Sensitive and reproducible gold nanostar@metal–organic framework-based SERS membranes for the online monitoring of the freshness of shrimps

“…2,3 During food spoilage, particularly the dissolution of rigor mortis stage of seafood, there is a dramatic increase in the number of microorganisms and massive decomposition of nitrogenous compounds, which result in the formation of α-keto acids, ammonia, organic acids, hydrogen sulfide (H 2 S), and various biogenic amines (BAs). 4,5 These compounds, which frequently have foul odors and high levels of toxicity, endanger food safety and are consequently commonly utilized as indicators of spoilage. In this regard, a range of fluorescent, colorimetry-based interface sensors have been reported for use in real-time and simple food spoilage monitoring.…”