The Effect of Magnetic Nanoparticles Plus Microwave Thawing on the Volatile Flavor Characteristics of Largemouth Bass (Micropterus salmoides) Fillets

Magnetic nanometer combined with microwave: Novel rapid thawing promotes phenolics release in frozen-storage lychee

Magnetic nanometer combined with microwave thawing (MN-MT) could become a novel solution to challenges uneven and overheating of microwave thawing (MT), while retaining high thawing efficiency, compared to conventional water immersion thawing (WT). In this study, MN-MT was applied to thaw fruit (lychee as an example) for the first time, and was evaluated by comparison with WT, MT and water immersion combined with microwave thawing (WI-MT). Results showed that MN-MT could significantly shorten the thawing time of frozen lychee by 80.67%, 25.86% and 18.83% compared to WT, MT and WI-MT, respectively. Compared to WT, MN-MT was the only thawing treatment which significantly enhanced the release of quercetin-3-O-rutinose-7-O-α-l-rhamnoside, according to HPLC-DAD. Meanwhile, thermal-sensitive procyanidin B2, phenylpropionic acid and protocatechuic acid were found to be protected from degradations only by MN-MT based on UPLC-ESI-QTOF-MS/MS results. In summary, MN-MT is a potential novel treatment for rapid thawing and quality maintenance of frozen fruits.

Effects of magnetic nanoscale combined radio frequency or microwave thawing on conformation of sea bass myosin heavy chain: a molecular dynamics study

BACKGROUND

The consumption of frozen foods inevitably involves a thawing process. Protein conformation changes during a short thawing process and the quantification of their effects remains challenging. Molecular dynamics simulations can be used to evaluate the conformational changes of protein occurring in food processing.

RESULTS

In the present study, four different thawing methods were used [i.e. magnetic nanometer combined with microwave thawing (MT-Mag), magnetic nanometer combined with radio frequency thawing (RT-Mag), radio frequency thawing (RT) and microwave thawing (MT)] to change the conformation of myosin heavy chain (MHC). The results obtained showed that, compared with the fresh sample, the hydrogen bond number and radius of gyration of the RT-Mag and RT groups were less decreased. Visual molecular dynamics STRIDE analysis showed that the content of the α helix was relatively high in the RT-Mag and MT-Mag groups.

CONCLUSION

These simulation results indicate that RT-Mag can be used as an effective method for promoting the thawing process of fish and better stabilizing the protein structure. These conclusions provide a theoretical realization for understanding the protein conformational transition during the thawing process and the realization of quantification and also provide guidance for choosing better thawing conditions without loss of nutritional properties. © 2022 Society of Chemical Industry.

Characterization of the Key Aroma Constituents in Fried Tilapia through the Sensorics Concept

The object of this study was tilapia fish that were fried in soybean oil. Volatile compounds were extracted from the fish by ASE-HVE and were studied by GC-O-MS and the AEDA analysis method. A total of 30 aroma compounds were initially determined, and these compounds contribute to the aroma of fried tilapias. The key volatile compounds in fried tilapia were quantitatively analyzed by GC-MS, and the volatile compounds in soybean-fried tilapia were studied by flavor recombination and deletion experiments. Trimethylamine, hexanal, 2,3-dimethylpyrazine, dimethyl trisulfide, trans-2-octenal, 2,3-dimethyl-5-ethylpyrazine, (E)-2-nonenal, 2-propyl-pyridine, and (E,E)-2,4-decadienal were finally determined to be the key volatile compounds in soybean-fried tilapia.