Effect of Slurry Ice on the Functional Properties of Proteins Related to Quality Loss during Skipjack Tuna (Katsuwonus pelamis) Chilled Storage

Tandem Mass Tag-based proteomic analysis of protein changes in superchilled crayfish (Procambarus clarkii) presoaked with carrageenan oligosaccharides

To assess the effectiveness of carrageenan oligosaccharides (COs) in enhancing superchilling storage of crayfish, the physicochemical features of muscle and protein abundance in the refrigerated sample (RS), superchilled sample (SS) and COs soaked superchilled sample (CS) were evaluated. Microstructural and SDS-PAGE analyses suggested that CS exhibited fewer pores, with a microstructure and protein subunits distribution more similar to RS. Tandem Mass Tags quantitative proteomic analysis revealed 66 up-regulated differentially abundant proteins (DAPs) in the CS vs. SS batch, including myosin light chain 2, neural cadherin, integrin beta, lectin-like protein, toll-1, reticulon-1, and moesin/ezrin/radixin homolog 1, which facilitate cells adhesion and maintain membrane/cytoskeleton integrity. Eukaryotic Clusters of Orthologous Groups results confirmed that COs treatment increased the stability of crayfish myofibrillar proteins by up-regulating DAPs, which were concentrated in functional categories such as "posttranslation modification, protein turnover, chaperones", "signal transduction mechanisms", "energy production and conversion", and "cytoskeleton".

The drip loss inhibitory mechanism of nanowarming in jumbo squid (Dosidicus gigas) mantles: protein structure and molecular dynamics simulation

BACKGROUND

The magnetic nanoparticles plus microwave thawing (MNPMT), a new rewarming technology entitled 'nanowarming', can serve as an effective method to achieve rapid and uniform thawing, thus reducing drip loss. The purpose of this study was to decipher the drip loss inhibitory mechanism of MNPMT in jumbo squid (Dosidicus gigas) from the perspectives of protein structure and ice crystal recrystallization. A number of different techniques such as dynamic rheology, Raman spectra, intrinsic fluorescence measurement, and ultraviolet (UV) absorption spectra were conducted to analyze myofibrillar protein conformation and stability of jumbo squid. Scanning electron microscopy (SEM) and myofibrillar fragmentation index (MFI) were used to observe the growth of ice crystals. The interaction between magnetic nanoparticles (MNPs) and ice crystals was studied by using molecular dynamic (MD) simulation.

RESULTS

MNPMT exhibited the highest storage modulus (G') value at 90 °C, suggesting the protein conformation was more stable. The increase in α-helices, fluorescence intensity and characteristic absorption peak of MNPMT illustrated that MNPMT can effectively maintain the secondary and tertiary structure of the protein. Compared with cold storage thawing (CST) and microwave thawing (MT), the MFI value of MNPMT was significantly decreased (P < 0.01). The result of MD simulation showed that MNPs displayed a tendency to gradually approach the surface of ice crystals, and induced a certain degree of damage to the ice crystal surface, thereby markedly inhibiting ice crystal recrystallization.

CONCLUSION

MNPMT can reduce the drip loss by keeping the protein conformation stable and inhibiting the recrystallization of ice crystals during the thawing process. © 2022 Society of Chemical Industry.

Effect of slurry ice during storage on myofibrillar protein of Pseudosciaena crocea

In order to explore the effect of slurry ice on myofibrillar protein of Pseudosciaena crocea, the changes in myofibrillar protein and muscle microstructure during storage were studied with crushed ice as a control. During the storage period, the rate of decrease in myofibrillar protein content, Ca2+-ATPase activity, and total sulfhydryl groups in the slurry ice group was lower than in the control group (p < .05). There was a significant linear correlation between the hydrophobicity and the storage time (R crushed ice (4℃) = 0.9881, R slurry ice (4℃) = 0.9878, R slurry ice (-1℃) = 0.9674), and trichloroacetic acid (TCA) soluble peptide content was lower than in the control group at the same time. Slurry ice (-1℃) was optimal in maintaining protein content in P. crocea; the arrangement of myofibrils in P. crocea treated by slurry ice was compact and the gaps were small. Slurry ice can delay the denaturation and degradation of fish myofibrillar protein and maintain its quality.