Microwave vacuum evaporation as a potential technology to concentrate sugar solutions: A study based on dielectric spectroscopy

Unraveling the binding mechanisms of transglutaminase and substrate subjected to microwaves: Molecular docking and molecular dynamic simulations

Previous studies showed that transglutaminase (TGase) and microwaves acted synergistically to improve the functional properties of proteins. The mechanism behind this has yet to be elucidated. In this study, the phenomenon of microwaves enhancing TGase activity was experimentally validated. Molecular docking and molecular dynamics simulations revealed that moderate microwaves (105 and 108 V/m) increased the structural flexibility of TGase and promoted the orientation of the side chain carboxylate anion group on Asp255, driving the reaction forward. Also, TGase underwent partial transformation from α-helix to turns or coils at 105 and 108 V/m, exposing more residues in the active site and facilitating the binding of the substrate (CBZ-Gln-Gly) to TGase. However, 109 V/m microwaves completely destroyed the TGase structure, inactivating the enzyme. This study provides insights into the molecular mechanisms underlying the interactions between TGase and substrate subjected to microwaves, promoting the future applications of TGase and microwaves in food processing.

Do non-thermal effects exist in microwave heating of glucose aqueous solutions? Evidence from molecular dynamics simulations

The existence of microwave non-thermal effects in food processing is still debated. In this study, molecular dynamics (MD) simulations were performed to investigate the conformation, electrostatic profiles, and intramolecular hydrogen bonds (intra-HB) of glucose in aqueous solution under alternating electric fields of microwaves ranging from 0 to 10⁹ V/m at 2.45 GHz. The results showed a field-induced threshold of 10⁹ V/m. At the threshold, alternating microwaves reoriented the flexible moieties and thus enhanced the intra-HB. The conformational transition among gg, gt, and tg conformers at 10⁹ V/m possibly resulted from the uneven electrostatic potential and the increased intra-HB. In practice, the maximum electric field of microwaves is several times weaker than the threshold, verifying the absence of microwave non-thermal effects for glucose molecules in food processing. This study provides a novel strategy to evaluate the potential non-thermal effects of microwaves in food processing and the related underlying food safety issues.

Microwave Planar Resonant Solutions for Glucose Concentration Sensing: A Systematic Review

The measurement of glucose concentration finds interesting potential applications in both industry and biomedical contexts. Among the proposed solutions, the use of microwave planar resonant sensors has led to remarkable scientific activity during the last years. These sensors rely on the changes in the dielectric properties of the medium due to variations in the glucose concentration. These devices show electrical responses dependent on the surrounding dielectric properties, and therefore the changes in their response can be related to variations in the glucose content. This work shows an up-to-date review of this sensing approach after more than one decade of research and development. The attempts involved are sorted by the sensing parameter, and the computation of a common relative sensitivity to glucose is proposed as general comparison tool. The manuscript also discusses the key points of each sensor category and the possible future lines and challenges of the sensing approach.