Biochemical Composition and Quality Parameters of Raw and Cooked Refrigerated Patagonian Crabmeat (Ovalipes trimaculatus)

Changes in flavor quality of marinated Chinese mitten crab (Eriocheir sinensis) with vacuum pack during cold storage

In order to study the pattern of changes in quality of marinated Chinese mitten crabs (Eriocheir sinensis) during cold storage, three aspects of sensory, taste and odor were investigated. Sensory evaluation and total volatile basic nitrogen (TVB-N) were measured in viscera and abdomen muscle at 0, 7, 15 and 30 days of storage at 4°C. Sensory scores significantly declined at 15 d, coinciding with TVB-N levels exceeding 25 mg N/100 g. Taste profiling demonstrated distinct changes over the storage period. Arginine (Arg) in viscera and abdomen muscle decreased by 18.16 % and 43.26 %, respectively, while adenosine monophosphate (AMP) dropped to 48.46 and 22.22 mg/100 g after 15 days, contributing to loss of umami. Based on the correlation analysis, it was known that bitterness was related to freshness, with tyrosine (Tyr), phenylalanine (Phe), hypoxanthine (Hx) and hypoxanthine riboside (HxR) being more significant contributors to the bitterness. Gas chromatography-ion mobility spectrometry (GC-IMS) analysis attributed late-stage undesirable odors to the production of aldehydes and ketones, particularly heptanone, 3-hydroxy-2-butanone, heptanal and glutaraldehyde. This study provided valuable guide for improving the flavor quality of Chinese mitten crabs in the field of prepared dish.

Impact of frozen storage on physicochemical parameters and quality changes in cooked crayfish

Customers are increasingly opting for ready-to-eat and easy-to-prepare food products, such as cooked crayfish. It is highly valued for its unique taste, tender meat, and nutritional properties. Therefore, we conducted an investigation into its quality parameters over an 8-week period at -20 °C. Parameters such as water distribution, oxidation reactions, color, microstructure, texture properties, and physicochemical parameters were examined. The physicochemical results indicated that as the storage time increased, the levels of pH and TVB-N (total volatile basic nitrogen) showed a significant increase, while the water holding capacity decreased significantly (P < 0.05). After two months of frozen storage, the carbonyl content and TBARS (thiobarbituric acid reactive substances) increased to 4.15 ± 0.16 nmol/mg protein and 1.6 ± 0.00 mg/kg, respectively. Additionally, the total sulfhydryl content decreased to 4.91 ± 0.10 mol/105 g protein, which had an impact on the quality of the crayfish. Electron microscopy revealed that with increasing storage time, the fiber structure gradually deteriorated due to water crystallization, leading to severe damage and breakage of muscle fibers. Interestingly, these changes related to storage affected color and texture parameters, thereby influencing the overall quality of the crayfish.

Comparison of freezing and heating treatment sequence on biochemical properties and flavor of swimming crabs (Portunus Trituberculatus) meat during freeze-thaw cycles

The objective of this study was to compare the effect of freezing and heating treatment sequences on the biochemical properties and flavor of crab (Portunus trituberculatus) meat during freeze-thaw cycles. The results showed that pH, color, K and microstructure changes in the H-F group were not significant with increasing number of freeze-thaw cycles, but TVB-N values increased and WHC values decreased. However, with the increase in the number of freeze-thaw cycles, pH and WHC significantly decreased and TVB-N, L* and K values significantly increased in the C and F-H groups. Proteins were degraded in all groups, but the lower degree of degradation occurred in the H-F group. Although the total free amino acid content decreased with increasing number of freeze-thaw cycles in each group, the high content of AMP and IMP in the H-F group suggested that it still had a better flavor.