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With the development of modern agricultural technology and the in-depth research of the biological effect of magnetic field, magnetic field technology has been widely used in various fields of agricultural science. Appropriate magnetic field conditions such as proper intensity, waveform, and frequency can give rise to specific non-thermal effects on agricultural raw materials, which can regulate the metabolism, respiration and mass and heat transfer efficiency of biological tissues and cells, mainly by influencing water cluster, cell morphology, biomolecular activity, and gene expression. Therefore, compared with other physical processing methods, its effects manifest more slowly. Moreover, the same magnetic field parameters could show different effects on different processed objects. At present, magnetic field technology has been verified and applied in the field of agricultural products processing, mainly including assistance in the preservation, sterilization, fermentation, and extraction of agricultural products. This article summarizes the current status of research and application of magnetic field biochemical technology in agricultural products processing, and discusses the existing problems and future trends, which will provide a reference for researchers interested in the application of this technology in the agricultural field.

The weak magnetic field has recently attracted much attention for improving the quality of frozen food due to its mild effectiveness and near-complete transmission through the food matrix. This study aimed to explore the effect of the magnetic field with 1 mT and 50 Hz on the freezing process and storage quality of pork and beef. The results showed that the freezing point of beef stored under the magnetic field was −1.7 °C, which was 0.5 °C lower than that of conventional frozen (CF) groups, and the phase transition times of pork and beef were reduced by 55.56% and 50.00%, respectively. The magnetic field maintained higher water-holding capacity and decreased drip loss and cooking loss for both types of meat. Coherently, the evaporation and redistribution of water was inhibited by MF, as indicated by the magnetic resonance imaging results. The magnetic field also effectively moderated the hardening in texture, odor deterioration and color change of frozen pork and beef. Less accumulation of free amino acids suggested the degradation of protein was suppressed under magnetic field. The present study would provide a scientific reference for the application of weak magnetic field in meat preservation. • Magnetic field improved water-holding capacity and texture of frozen meat. • Magnetic field could shorten the phase transition times. • Magnetic field restricted water migrations and alleviated myofibrillar denaturation. • Undesirable odor compounds were not detected under magnetic field. [ABSTRACT FROM AUTHOR]

The effect of magnetic field (MF) on the postharvest quality and energy metabolism of green chili was investigated. An MF of 4 mT intensity was applied during the refrigeration of green chili pepper. Conventional refrigeration (CR) was used as a control, and the chili pepper fruit was stored at 10 °C and sampled at 1, 5, 10, 20, and 30 d after harvest. The results showed that MF inhibited the senescence of chili pepper and quality deterioration, as evidenced by higher water content, vitamin C (VC) and flesh firmness as well as lower weight loss and decay incidence. The decrease of hue angle values and the chlorophyll content were remarkably depressed by MF treatment, indicating an efficient delay in the yellowing of chili pepper. In terms of metabolism, MF sustained high adenosine triphosphate (ATP) content, energy charge (EC), and activities of key enzymes engaged in energy metabolism (H+-ATPase, Ca2+-ATPase, succinate dehydrogenase, and cytochrome C oxidase). Additionally, there was an increase in the concentration of major energy metabolites, including citric-acid, isocitric-acid, D-Glucose-6-phosphate, and D-Fructose-6-phosphate. These results suggested that MF may be used as a promising strategy for preventing the decay of postharvest green chilies and prolonging their shelf life. [Display omitted] • MF slowed down senescence and quality deterioration of green chilies. • MF inhibited the loss of chlorophyll and VC content. • MF sustained ATP, EC, and key enzyme activities for energy metabolism. • Major energy metabolites were maintained at high level by MF. [ABSTRACT FROM AUTHOR]

As an emerging physical technology, magnetic fields have been used to improve the quality of frozen and refrigerated foods. This study compared the effect of applying a static magnetic field (2 mT) at different stages of freezing and storage on the quality of frozen dough. Results suggested that the magnetic field significantly impacted frozen dough quality. It not only prevented the formation of ice crystals during the pre-freezing stage but also inhibited ice crystal growth during the following frozen storage. This effect helped to maintain the integrity of gluten proteins and their adhesion to starch granules by preventing the breakage of disulfide bonds and the depolymerization of gluten macromolecules. It was also observed that yeast inactivation and glutathione release were reduced, resulting in improved air retention and air production capacity of the dough. This, in turn, led to a more appealing volume and texture quality of the finished bread. • Magnetic field (MF) improved volume and texture quality of frozen wheat dough. • MF inhibited ice crystal formation and growth during pre-freezing and frozen storage. • MF prevented disulfide bond breakage and gluten macromolecule depolymerization. • Yeast inactivation and glutathione release were reduced under MF. [ABSTRACT FROM AUTHOR]

Due to the serious bacterial infection of skin and the waste of petroleum-based materials, there is an urgent need to develop natural biodegradable wound dressings with high antibacterial activity. Phosvitin (PSV) has shown its natural antioxidant and antibacterial properties, making it an excellent material for preparing wound healing dressings. In this study, we investigated the effect of magnetic field on the preparation of PSV-Microcrystalline Cellulose (MCC) composite hydrogels in 1-Allyl-3-methylimidazolium chloride (AmimCl) system. The results showed that the prepared hydrogels exhibited homogeneous surface structure, suitable swelling capacity and elasticity modulus, and sufficient thermal stability. The excellent antibacterial and antioxidant activities of hydrogels were mainly resulting from AmimCl and PSV, respectively, and the properties were enhanced after magnetic field treatment. The proteomics analysis indicated that AmimCl can readily penetrate the biological membranes of Staphylococcus aureus (S. aureus), upsetting the metabolism and reducing the virulence. The hydrogels showed great blood compatibility. Compared with the commercial materials, the 5 mT-treated hydrogels presented a comparable wound healing rate in the full-thickness skin injury model. On day 7, the wound healing rate of the 5 mT group reached approximately 84.40 %, which was significantly higher than that of the control group, 72.88 % (P < 0.05). In conclusion, our work provides experience for the development of biodegradable materials combined in ionic liquids and magnetic field, and explores their applications in wound healing dressings. [Display omitted] • The AmimCl is a green solvent and shows antibacterial activity against S. aureus. • Magnetic field can enhance the antibacterial and antioxidant properties of the materials. • 5 mT-treated hydrogels present a comparable wound healing rate as compared to the commercial Tegaderm. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microbial fermentation is a mainstream method for producing high-value compounds. • Applications of magnetic fields in microbial fermentation were summarized. • Magnetic field assisted microbial fermentation devices were illustrated. • Underlying mechanisms behind biological effects of magnetic fields were elaborated. The magnetic field application is emerging as an auxiliary physical strategy to facilitate rapid biomass accumulation and intracellular production of compounds. However, the underlying mechanisms and principles governing the application of magnetic fields for microbial growth and biotransformation are not yet fully understood. Therefore, a better understanding of interdisciplinary technologies integration, expanded magnetic field application, and scaled-up industrial implementation is crucial. In this review, the magnetic field characteristics, magnetic field-assisted fermentation devices, and the working mechanism of magnetic field have been reviewed comprehensively from both physical and microbiological perspectives. The review suggests that magnetic fields affect the biochemical processes in microorganisms by mediating nutrient transport across membranes, electron transfer during photosynthesis and respiration, enzyme activity and gene expression. Moreover, the recent advances in magnetic field application for microbial fermentation and conversion in biochemical, food and agricultural fields have been summarized. [ABSTRACT FROM AUTHOR]

This study was to investigate the protective effect of magnetic field (MF) on frozen dough processing quality. The texture, microstructure, rheological and physicochemical properties of wheat dough treated by freezing-thawing cycles under different magnetic flux densities (0, 2, 4, 6, 8, and 10 mT) were analyzed. Compared with conventional frozen dough, MF-treated frozen dough had lower hardness and higher elasticity. Scanning electron microscope exhibited that MF treatment minimized the freezing-induced damages on morphology of starch and gluten, which was consistent with the decreased tan δ in rheological analysis. Application of MF facilitated high relative crystallinity and gelatinization enthalpy in starch granules while the depolymerization of gluten macropolymer was inhibited as manifest with more ordered secondary structure and decreased free sulfhydryl groups. The integrated structure in MF-treated frozen dough resulted in lower free water content as shown by low field nuclear magnetic resonance. The results provided valuable knowledge for the MF-assisted freezing technology and made it possible to improve the freezing-induced deteriorations on wheat-based food. • Wheat dough was frozen/thawed with different magnetic field(MF) intensities. • Freezing-induced damages on starch granule and gluten were repaired by MF. • MF resulted in high starch crystallinity and lower gluten depolymerization. • MF caused a softer hardness and higher elasticity compared with frozen dough. [ABSTRACT FROM AUTHOR]

Strawberries are prone to rapid quality deterioration after harvest. Research has confirmed that a magnetic field can improve fruit quality during postharvest storage. However, how the magnetic field impacts the postharvest physiology of strawberries is far from being explored. In this study, the magnetic field (MF, 4 mT, and 50 Hz) was employed during the storage of strawberries at 4 °C for 1, 3, 5, 7, 10, and 15 d, and conventional refrigeration (CR) was used as the control. The results showed that the MF maintained better fruit quality, as indicated by lower decay incidence, declined weight loss, and greater firmness retention. The decrease in soluble solids content and titratable acidity of strawberries caused by respiratory depletion was also alleviated by MF. Furthermore, an improvement in the adenosine triphosphate level, energy charge, activity of enzymes (H+-ATPase, Ca2+-ATPase, succinate dehydrogenase, and cytochrome oxidase) involved in the respiratory metabolism, as well as primary respiratory metabolites (D -glucose, succinic acid, fumaric acid, and citric acid) were observed for the strawberries of MF group. Accumulations of hydrogen peroxide, superoxide anion, and malondialdehyde were suppressed with the application of MF. Overall, the MF contributed to maintaining higher energy and membrane integrity and function, regulating the levels of energy metabolism enzymes, and mitigating reactive oxygen species accumulation, which might be a part of the mechanism involved in retarding the senescence and decay of harvested strawberries. [Display omitted] • MF treatment maintained better strawberries' quality. • MF could maintain ATP content and energy charge. • MF could maintain energy metabolism enzymes activity. • MF treatment alleviated the accumulation of ROS. • MF treatment delayed the postharvest senescence of strawberries. [ABSTRACT FROM AUTHOR]

To promote NaOH pretreatment of corn stalk (CS), a continuous processing system uniting magnetic field and millimeter-scaled channel flow was established. First, four comparative pretreatments were conducted: (I) CS was pretreated with NaOH under traditional agitation; (II) CS was pretreated with NaOH in a flowing state inside the millimeter-scaled channel; (III) CS was pretreated with NaOH in a flowing state and under a static magnetic field; or (IV) CS was pretreated with NaOH in a flowing state and under a rotating magnetic field. By comparison, the highest pentose (121.22 mg/g dry CS) and hexose (287.04 mg/g dry CS) yields were obtained in the shortest pretreatment time with Pretreatment IV (8 h). Accordingly, the key parameters of Pretreatment IV were optimized as 6.71 Hz frequency, 0.50 L/min flow rate, and 1.02% NaOH concentration. Under these conditions, 439.24 mg sugars were released by 1 g dry CS during pretreatment and enzymatic hydrolysis. [ABSTRACT FROM AUTHOR]

The magnetic field is an emerging physical method used for food preservation, characterized by its high penetrability in food materials. The effect of a static magnetic field (MF, 2 mT) on frozen dough upon freeze-thaw treatments (3, 7, and 10 cycles) was investigated, with conventional freeze-thaw (CF) treatments being used as control. Results showed that the magnetic field ensured the baked bread made from dough a 17.59% larger specific volume and a 30.87% smaller crumb hardness. It accelerated the time for the dough to pass through the maximum ice crystal formation zone by 7 min and reduced the ice melting enthalpy from 63.55 J/g to 56.67 J/g after 10 freeze-thaw cycles. Nuclear magnetic resonance analysis suggested that the conversion of bound water to immobilized water and free water was inhibited. The yeast viability and activity were also better maintained, precisely as the observed increase of 18.18% and 42.23% in its survival and gassing power. After 10 freeze-thaw cycles, the free disulfide (SH) content was determined to be 1.642 μmol/g for CF doughs and 1.624 μmol/g for MF ones, respectively. A reduction of 24.26% in glutenin macropolymer depolymerization was achieved, indicated a more stable gluten structure under the magnetic field. [Display omitted] • Magnetic field improved the quality of frozen dough bread. • Lower depolymerization degree was detected in gluten using magnetic field. • Yeast survival and gassing power were better preserved under magnetic field. • Magnetic field inhibited water migrations and status change. [ABSTRACT FROM AUTHOR]