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This study aimed to investigate the effects of temperatures of 30–90°C on myosin denaturation and aggregation in sea bass (Lateolabrax japonicus) during setting. The result indicated that the myosin of sea bass began to form gels at 60°C, and surface hydrophobicity increased by around 8.9% at 40°C and reached its maximun at 60°C. During setting at 40°C and 60°C, the ratios of α‐helix of myosin reduced gradually and finally decreasing by 17.1% and 25.2%, respectively. Incubating at 90°C, α‐helix continued to transform into random coil. Association with the results of surface morphology, it further confirmed that the temperatures of 40°C and 60°C were two important denaturation and aggregation temperatures. At 90°C, myosin of sea bass formed a fine and dense gel network under the joint action of nondisulfide covalent bond, disulfide bond and hydrophobic interaction. Practical applications: The raw materials for marine surimi are becoming scarcer with marine overfishing and the increasing demand for surimi. Sea bass, an important economic mariculture fish in China, has white meat and less bone spur and is advantageous for the development of surimi products as raw materials. During heating of surimi, the change of myosin structure is a main important key to forming a gel network. This research revealed the changes of sea bass myosin from denaturation, aggregation to gel formation during heating and provided a theoretical basis for the processing of sea bass surimi. [ABSTRACT FROM AUTHOR]

To quantitatively analyze shrimp peelability, the peeling work was measured using a texture analyzer by normalizing the total peeling work to separate the shell and shrimp muscle. The results showed the developed method of normalized peeling work was valid in accessing the peelability of shrimp and was independent of the shell removal area and shrimp size; no significant difference was observed for abdominal segments (AS) 1, 2, and 3 with peeling work 8.36, 7.90, and 8.02 mJ/g, respectively. Furthermore, the peeling work decreased after 4 hr of freezing (4.07 mJ/g) and 8 hr of ice‐slurry (5.11 mJ/g) pre‐treatment for AS, and after 8 hr of freezing (19.28 mJ/g) for tail segments. Moreover, as compared to raw shrimps, frozen/ice‐slurry pre‐treated shrimps displayed larger shell‐loosening gaps. The quantitative analysis method for measuring the peeling efficiency and peeling performance of shrimps could be useful to optimize the shrimps peeling. Practical applications: The quantitative method to measure the peelability of shrimps provides a relatively accurate reference for enterprises to optimize the production process. [ABSTRACT FROM AUTHOR]

Twelve categories of polar lipids (PLs) were quantified in round scad and hairtail during salt‐drying with electrospray ionization‐tandem mass spectrometry based on lipidomics. The major species were phosphatidylcholine (PC), phosphatidylethanolamine (PE), and ether‐linked PC (ePC), accounting for 67.8%, 11.1%, and 9.7% of total PLs in the raw round scad respectively, and 74.3%, 7.3%, and 10.9% in raw hairtail. Among the 272 and 263 kinds of PLs molecules detected in the two raw fish respectively, only 125 and 94 PLs were strongly affected by salt‐drying, including 28 PCs, 23 PEs, 21 ePCs, 9 phosphatidylinositols (PIs), 14 phosphatidylserines/phosphatidic acids/phosphatidylglycerols (PSs/PAs/PGs), 12 lysophosphatidylcholines (LPCs), 5 lysophosphatidylethanolamines (LPEs), 9 ether‐linked PEs (ePEs), 4 sphingomyelins (SMs) in round scad, and 21 PCs, 17 PEs, 15 ePCs, 10 PIs, 7 PSs/PAs/PGs, 9 LPCs, 5 LPEs, 6 ePEs, 4 SMs in hairtail. Salt‐drying had a very different effect on the two fish. Ultimately, the total PLs content decreased slightly (p >.01) in salt‐dried round scad product while increased significantly in hairtail final product (p <.01). Practical applications: The change of PLs caused by salt‐drying is closely related to the flavor and quality of fish products, and is very important for fish preservation and processing. [ABSTRACT FROM AUTHOR]

To assess the impact of ozonated water pretreatment on fish quality, Nile tilapia fillets were sterilized by 4.5 mg/L ozone-containing water for 30 min and stored at −18 ± 1C for 180 days. Untreated fillets were used as controls. Quality changes during storage were assessed by chemical, microbiological analysis, color and texture measurements in both groups. The results showed that the pH did not significantly differ in both groups at various time points during storage and did not exhibit a significant correlation with the microbiological data, which reflects the changes in quality during frozen storage. Malondialdehyde content and K-values increased in the control and ozone-treated fillets samples after 180 days of frozen storage. Ozonated water treatment had antimicrobial, bleaching and textural quality enhancement effects on tilapia fillets processing. In conclusion, the tilapia fillets quality can be improved partly and shelf life can be extended well after ozonated water pretreatment. Practical Applications We assessed quality during storage in Nile tilapia fillets after ozonated water treatment. Ozonated water treatment improves the quality and extends the shelf life of the fish. Hardness, gumminess, springiness and chewiness were enhanced by pretreatment. This study is of interest to the aquatic food industry and the consumers. [ABSTRACT FROM AUTHOR]

ABSTRACT The effects of different color retention methods on tilapia fillets were studied by evaluating the color of red muscle, extractable myoglobin, content of metmyoglobin and carbon monoxide (CO), and profiles of absorption spectra. The results showed that CO had a significant effect on red muscle coloration. The time spans for the euthanizing and the packaging methods required by red muscle to obtain optimum a* values were 15 and 40 min, respectively. Extractable myoglobin content increased, while metmyoglobin decreased during the initial color retention treatment. Treatment for 15 min using the euthanizing method or for 40 min using the packaging method gave peak values of CO content in the fillets. The a* value was positively correlated with the CO content and myoglobin extractability, but negatively correlated with the metmyoglobin content. A slight redshift in absorption from 410 to 415 nm was observed for red muscle tissue and from 405 to 408 nm for ordinary muscle tissue. PRACTICAL APPLICATIONS Red muscle tissue is very susceptible to discoloration. This discoloration is highly undesirable to consumers, thus leading to a lower price than products with a more favorable color. Therefore, several producers are searching for effective ways to solve the problem of discoloration. The euthanizing and packaging methods were assumed to be effective ways to induce the tilapia fillets with bright color. Because of a lack of information on the variation of tilapia fillets during CO treatment, the objective of this study was to compare the effect of two treatments on the color of tilapia muscle tissue. [ABSTRACT FROM AUTHOR]