Elsevier

Food Chemistry

Volume 407, 1 May 2023, 135092
Food Chemistry

Effects of magnetic field-assisted immersion freezing at different magnetic field intensities on the muscle quality of golden pompano (Trachinotus ovatus)

https://doi.org/10.1016/j.foodchem.2022.135092Get rights and content

Highlights

  • The effects of different intensities of MIF on Trachinotus ovatus were investigated.

  • The centrifugal and cooking loss of fish samples was reduced by MIF-20 mT.

  • The mobility of water of fish samples was reduced by MIF-20 mT.

  • The damage of ice crystals to muscle tissues was decreased by MIF-20 mT.

Abstract

This study evaluated the effects of magnetic field-assisted immersion freezing (MIF) with different magnetic field intensities (0, 20, 40, 60, and 80 mT) on the freezing curves, ice crystal area, microstructure, and physicochemical properties of golden pompano (Trachinotus ovatus) muscle. The result showed that, compared with refrigerator freezing (RF) and immersion freezing (MIF-0), magnetic fields prolonged the freezing time. However, the centrifugal loss and cooking loss of MIF-20 were 23.55 % and 29.18 % lower than those of MIF-0 group, respectively (P < 0.05). Low field-nuclear magnetic resonance results showed that MIF-20 group exhibited more homogeneous of water distribution and higher water content, the T22 was 20.59 % shorter than of MIF-0 (P < 0.05). Microscopic observations confirmed that the MIF-20 group had the smallest and the most evenly distribution of ice crystals. Therefore, MIF at 20 mT intensity can effectively improve the muscle qualities of frozen golden pompano.

Introduction

Golden pompano (Trachinotus ovatus) is among the most economically relevant marine fish species due to its tender meat, lack of intermuscular spines, and pleasant flavour. Therefore, stable and high-yield breeding methods have been developed for the production of this species. China is one of the largest producers and distributors of golden pompano, with a total production of 243,908 tons in 2021 (Bureau of Fisheries of the Ministry of Agriculture, 2021). However, fish are highly susceptible to spoilage due to their high water content, fragile tissues, and high microorganism loads. Therefore, preservation measures must be taken to ensure product quality (Mokrani, Oumouna, & Cuesta, 2018). Currently, various preservation methods such as drying, curing, and low-temperature storage (e.g., cooling and freezing) are extensively used for the preservation of fish. Among them, freezing is the most widely applied and effective way to preserve fish.

In 2019, approximately 56 % of the golden pompano in China was marketed in frozen form, and almost all golden pompano exports are frozen (China Fisheries Association, 2020). However, the large and irregular ice crystals formed during freezing via traditional freezing methods can destroy the muscle tissues, which severely decreases fish meat quality. Therefore, additional efforts are needed to improve the quality of frozen golden pompano and maintain its freshness, nutritional composition, and flavour. Recent studies have confirmed that the quality of frozen products is prominently affected by the morphology and distribution of the ice crystals formed during the freezing process (Wang et al., 2018). Small and uniformly distributed ice crystals can minimise the mechanical damage to tissues and cells, and decrease the loss of muscle juice during freezing and thawing, thereby optimally preserving the quality of frozen foods (Ninagawa, Eguchi, Kawamura, Konishi, & Narumi, 2016).

During the freezing process, smaller and more homogeneously distributed ice crystals can be obtained by applying physical field such as pulsed electric fields (Zhang, Ding, Zhou, Zhang, Shi, Zou, & Xiao, 2022), ultrasound (Sun, Zhao, Zhang, Xia, Sun, & Kong, 2019), ultra-high pressure (Wang, Zhang, Qiao, Li, Shi, Wang, & Shi, 2022), and magnetic fields (Zhou, Jin, Hong, Yang, Cui, Xu, & Jin, 2021), thus improving the quality of frozen food. However, these novel freezing approaches still have several limitations such as the generation of oxidative species, the need for expensive equipment, pressure damage to muscle tissues, and unclear mechanisms, and therefore are currently only applied at a laboratory scale.

Among the novel freezing methods mentioned above, magnetic field-assisted freezing (MF) technology does not require complex equipment and the procedure is generally safe, convenient, cost-effective, non-toxic, and environmentally friendly (Qi, Sun, Wang, & Zhao, 2019). Previous studies have demonstrated that MF can optimise the nucleation of ice crystals, reduce the area of ice crystals formed within tissues, and improve the overall quality of frozen products. Previous studies have demonstrated that magnetic fields can affect the spin direction of electrons and nuclei in water molecules, in addition to directly affecting the position, oscillation, and rotation of water molecules to avoid their aggregation (Kaku, Kawata, Abedini, Koseki, Kojima, Sumi, et al., 2012). The hydrogen bonds between water molecules become weaker and their average numbers decrease after magnetisation. In turn, this not only decreases the formation of water molecule clusters but also reduces the size of the ice crystals formed during the freezing process (Otero, Rodríguez, Pérez-Mateos, & Sanz, 2016).

In recent years, the relationship between the intensity of the magnetic field applied to assisted freezing and the quality of the food has been less clear. The optimal magnetic field intensity may be determined by the type of food, the content and type of ferromagnetic particles in the food (Kobayashi, & Kirschvink, 2014). It is fundamental and essential to investigate the quality changes of different food matrices in MF process. Therefore, the application of MF technology to different food matrices requires extensive research. The research on MF technology has mostly focused on plant-based foods such as bread dough (Zhou, Jin, Hong, Yang, Cui, Xu, & Jin, 2021), blueberries (Tang, Shao, & Tian, 2019), and cucumbers (Zhang, Yang, & Deng, 2021). However, very few studies have characterised the preservation of aquatic products through MF technology. Food composition is highly complex and the composition of different kinds of foods can vary widely due to differences in cell structure and other factors. Therefore, the effect of MF may vary considerably depending on the food type and its composition, which highlights the need to evaluate the applicability of MF for the preservation of aquatic raw materials such as fish.

This study investigated the effects of MF with different magnetic field intensities (20–80 mT) on golden pompano muscle quality to identify the optimal freezing parameters of MF technology and verify whether this approach delivers superior results compared to conventional freezing methods such as refrigerator freezing (RF) and immersion freezing (MIF-0).

Section snippets

Chemicals

Optimal cutting temperature compound (OCT compound), eosin staining solution (0.5 % concentration), and neutral gum were purchased from Wuhan Servicebio Technology Co., ltd (Wuhan, China). All chemicals and reagents were of analytical grade.

Experimental design

A schematic diagram of the equipment used in this experiment is shown in Fig. 1A. A constant temperature circulating tank (MD5-100-G, Suzhong, China) was used to deliver cooling water to a magnetic field-assisted freezer for heat dissipation of the Helmholtz

Freezing curve

The freezing curve of food materials reflects the changes in the central temperature of a given sample throughout the freezing process. Previous research has repeatedly confirmed that smaller and more uniform ice crystals are formed when food is frozen as quickly as possible, thereby preserving the quality of the frozen products. Food is a complex system composed of various components, all of which are presumably affected differently by magnetic fields. Therefore, the effects of MF were first

Conclusion

This study investigated the effects of RF and MIF on ice crystal formation and the quality of golden pompano muscle. The results indicated that an appropriate magnetic field intensity (20 mT) inhibited the formation of large ice crystals, promoted a uniform distribution of ice crystals, and weakened the mechanical damage of muscle tissue by ice crystals. The MIF-20 freezing treatment reduced the centrifugal loss, cooking loss, lightness values, water-holding capacity, and hardness of frozen

CRediT authorship contribution statement

Jieqian Zhou: Writing – original draft, Visualization, Data curation. Xiuping Dong: Supervision. Baohua Kong: Supervision. Qinxiu Sun: Conceptualization, Methodology, Writing – review & editing. Hongwu Ji: Validation, Investigation. Shucheng Liu: Conceptualization, Methodology, Writing – review & editing.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This study was supported by the Ocean Young Innovative Talents Project of Zhanjiang [grant number 2021E05015]; Young Innovative Talents Project of Guangdong General Universities [grant number 2020KQNCX028]; Doctoral Research Initiation Project of Guangdong Ocean University [grant number R20047]; Modern Agro-industry Technology Research System of China [grant number CARS-48]; and Guangdong Innovation Team of Seafood Green Processing Technology [grant number 2019KCXTD011].

References (39)

  • Q. Sun et al.

    Ultrasound-assisted thawing accelerates the thawing of common carp (Cyprinus carpio) and improves its muscle quality

    LWT-Food Science and Technology

    (2021)
  • Q. Sun et al.

    The comparison of ultrasound-assisted immersion freezing, air freezing and immersion freezing on the muscle quality and physicochemical properties of common carp (Cyprinus carpio) during freezing storage

    Ultrasonics Sonochemistry

    (2019)
  • Q. Sun et al.

    Ultrasound-assisted immersion freezing accelerates the freezing process and improves the quality of common carp (cyprinus carpio) at different power levels

    LWT-Food Science and Technology

    (2019)
  • J. Tang et al.

    Effects of different magnetic fields on the freezing parameters of cherry

    Journal of Food Engineering

    (2020)
  • A. Thanonkaew et al.

    The effect of metal ions on lipid oxidation color and physicochemical properties of cuttlefish (Sepia pharaonis) subjected to multiple freeze-thaw cycles

    Food Chemistry

    (2006)
  • E. Toledo et al.

    Influence of magnetic field on physical-chemical properties of the liquid water: Insights from experimental and theoretical models

    Journal of Molecular Structure

    (2008)
  • Y. Wang et al.

    The effect of a static magnetic field on the hydrogen bonding in water using frictional experiments

    Journal of Molecular Structure

    (2013)
  • C. Wang et al.

    Effects of ultrasound and ultra-high pressure pretreatments on volatile and taste compounds of vacuum-freeze dried strawberry slice

    LWT-Food Science and Technology

    (2022)
  • Z. Wu et al.

    The impact of quick-freezing methods on the quality, moisture distribution and microstructure of prepared ground pork during storage duration

    Ultrasonics Sonochemistry

    (2021)
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