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Based on an analysis of 51-year (1965–2015) data, the influence of El Nino-Southern Oscillation (ENSO) events on tropical cyclone (TC) activity is examined over the western North Pacific (WNP). The total number of TCs formed in the entire WNP reduces by about 3.4 TCs per year in La Nina years, whereas TCs have an equivalent genesis number between El Nino years and climatology. During El Nino years, the frequency of TC formation increases remarkably in the southeast quadrant (140°E–180°, 0°–17°N) and decreases in the northwest quadrant (120°–140°E, 17°–30°N). During La Nina years, TCs tend to form in the northwest and southwest quadrants (120°-140°E, 0°–17°N) quadrants. TCs tend to become long-lived in the peak season (from July to September) of El Nino years and during strong El Nino events. TC genesis shows a southeastward positive shift in terms of lifetime and intensity during El Nino years, thus more super TCs (winds ≥ 58.64ms−1) are formed in the southeast quadrant. Further analysis using the genesis potential index (GPI) indicates that the interannual variations in the TC genesis and track are significantly influenced by a combination of large-scale dynamic and thermodynamic conditions.

The iTRAQ-based quantitative proteomic strategy was used to reveal the effects of magnetic nanoparticles plus microwave thawing (MNPMT) on the largemouth bass fillets quality. A total number of 47 proteins were identified as differentially abundant proteins (DAPs) in fillets treated by microwave thawing (MT), while 13 DAPs were in MNPMT. Bioinformatics analysis of Gene ontology (GO) enrichment, Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment, Protein-protein interaction (PPI) and subcellular localization prediction of DAPs showed that many DAPs were involved in protein structure, metabolic enzymes, protein turnover and so on. The correlation analyses indicated that 14 DAPs were significantly related with the fillet quality traits. Besides, several discovered proteins might be potential protein markers for pH, color, cooking loss and centrifuge loss of thawed largemouth bass fillet quality. These results provided a further understanding of quality stability of largemouth bass fillet treated by MNPMT from the perspective of proteomics.

Serious quality deterioration can occur with suboptimal thawing, and thus innovative thawing technologies may have an important role in improving the final quality of frozen foods. In recent years, although several new thawing technologies have been extensively studied, such as ultra-high pressure assisted thawing, ultrasound-assisted thawing, high-voltage electrostatic field thawing, ohmic thawing, and radio frequency thawing, more research is needed to make them more applicable to thawing of food industrially. A better evaluation of the impact of thawing is needed to help move new thawing technologies forward. This review discusses the principles involved, the applications to different types of foods, modeling of the various processes, new evaluation techniques, and patents obtained for the different systems. The benefits and weaknesses of these systems are also discussed to provide a more complete review of these new thawing techniques. This review will, hopefully, encourage additional work that may help reach the goal of having better food thawing systems.

The volatile flavor characteristics of largemouth bass (Micropterus salmoides) fillets thawed by magnetic nanoparticles plus microwave thawing (MNPMT) were compared with those of fresh samples thawed by chill storage thawing (CST) and microwave thawing (MT). The strategies of headspace solid-phase microextraction (HS-SPME), gas chromatography mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), aroma extract dilution analysis (AEDA), and sensory evaluation were applied to analyze the aroma-active compounds. The results of GC-MS showed that 24 kinds of volatile compounds existed in largemouth bass fillets. Orthogonal partial least squares discriminate analysis (OPLS-DA) (R2Y = 0.979, R2Y = 0.98, Q2 = 0.695) showed ethanol, hexanal, 2,6,10,14-tetramethyl-pentadecane, and (E)-9-octadecenoic acid were responsible for the flavor differences in MNPMT, MT, and CST. In GC-O measurement, 14 kinds of volatile compounds were detected, and MNPMT had similar aroma-active compounds with the fresh sample. The grassy (score = 1.58) and leafy (score = 0.75) odors were weak in MT, but the fishy odors (score = 1.5) were strong. All results showed the MNPMT samples had less changes in aroma composition compared with the fresh sample.

Recrystallisation often occurs in the freeze‐thaw cycles and results in poor food quality. This study was undertaken to analyse the effects of recrystallisation on the changes of protein conformation and moisture migration within red seabream fillets after the freeze‐thaw cycles. The UV second‐derivative spectroscopy, intrinsic fluorescence measurement and Raman spectroscopy were employed to evaluate the protein conformational changes. The Low‐field NMR spectra analysis was used to evaluate moisture migration. The results indicated that the freeze‐thaw cycles altered the secondary and tertiary structure of proteins. It was noticed that interactions between water and protein molecules were decreased gradually and eventually induced the thermal instability of the myosin molecules. The immobilised water content declined and the free water content increased. There were significant destructions in fillet muscle microstructure. These observations unambiguously reflect how the recrystallisations affect the protein conformation and moisture migration patterns of red seabream fillets during freeze‐thaw cycles.

In order to evaluate the effects of magnetic nanoparticles plus microwave (MNPMT) or far-infrared (MNPFT) thawing on protein conformation changes and moisture migration of red seabream (Pagrus major) fillets, cold storage thawing, microwave thawing, MNPMT, far-infrared thawing and MNPFT were subjected to red seabream fillets. DSC and dynamic rheology were conducted to analyze physicochemical changes. Raman spectra before and after isotope H/D exchange, intrinsic fluorescence and UV second derivative spectra were carried out to explore myofibrillar protein structural changes. Low-field NMR was used to test water migration. SEM was performed to observe fiber microstructure. Results indicated that MNPMT and MNPFT both had a desirable thermal stability and gelation property. Besides, both showed stable protein secondary and tertiary structure. Immobilized water in them also had no significant changes compared with fresh sample. This research provided some novel thawing technologies for application in food industry.

Ultrasound assisted vacuum thawing (UVT) or microwave vacuum thawing (MVT) with red seabream fillets were compared to fresh, chill storage thawing, vacuum thawing, microwave thawing and ultrasound thawing. The thermal stability and gelation properties were studied with DSC and dynamic rheology, respectively. Raman spectra before and after H/D isotope exchange and intrinsic fluorescence were used to measure protein secondary and tertiary structure. Low-field NMR was done to measure water migration. The two thawing techniques both retained actin thermal stability and generally retained more stable tertiary structures than the other thawing methods. MVT showed a desirable viscoelasticity of muscle proteins and UVT had a relatively stable secondary structure. There were no significant changes in free water. Thus, UVT and MVT could be used to improve the physicochemical properties of proteins during thawing of fillets.

The effects of magnetic nanoparticles combined with microwave thawing (MNPMT) and magnetic nanoparticles combined with far-infrared thawing (MNPFT) on the freshness and amines content of red seabream fillets were investigated. Four thawing methods were used: microwave thawing (MT), far-infrared thawing (FIRT), magnetic nanoparticles combined with microwave thawing (MNPMT) and magnetic nanoparticles combined with far-infrared thawing (MNPFT). The quality of the fresh sample, the sample after thawing and thawed sample after being stored for 6 h were compared by measuring the freshness indexes such as the volatile amino nitrogen content, thiobarbituric acid content, pH value, total number of viable colonies, and the food safety evaluation indexes such as the formaldehyde, dimethylamine, trimethylamine and putrescine contents. The results showed that MNPFT and MNPMT can maintain better freshness than microwave and far-infrared thawing, and the increase in amines content was significantly inhibited.

This study investigated the effects of different thawing methods on the quality of largemouth bass. The viscoelastic properties of proteins in Ultrasonics combined with microwave thawing (UMT) and Ultrasonics combined with far-infrared thawing (UIT) samples were closer to FS, which was an indication of good gelation and gel quality. Zeta potential, Raman spectra before and after H/D isotope exchange were used to measure the protein aggregation and the secondary structure of protein. Fourier transform Raman spectra and Raman spectra have been used to investigate the chemical changes in fish lipid during lipid oxidation. Results indicated that both UMT and UIT showed protein stability and gelation property. Thus, it was proved that UMT and UIT could be potentially used to improve the fish quality during thawing process.