The principles of high voltage electric field and its application in food processing: A review

Innovative Approaches for Recovery of Phytoconstituents from Medicinal/Aromatic Plants and Biotechnological Production

Continuously growing demand for plant derived therapeutic molecules obtained in a sustainable and eco-friendly manner favors biotechnological production and development of innovative extraction techniques to obtain phytoconstituents. What is more, improving and optimization of alternative techniques for the isolation of high value natural compounds are issues having both social and economic importance. In this critical review, the aspects regarding plant biotechnology and green downstream processing, leading to the production and extraction of increased levels of fine chemicals from both plant cell, tissue, and organ culture or fresh plant materials and the remaining by-products, are discussed.

Post-thawing metabolite profile and amino acid oxidation of thawed pork tenderloin by HVEF-A short communication

The post-thawing quality, metabolite profile and amino acid oxidation of frozen pork tenderloin following the use of a high-voltage electrostatic field (HVEF) were investigated in this study. There were not significant differences of pH for pork thawed by air and HVEF, which were consistent with the lactic acid level and glycogen content. No changes in the tenderness of thawed pork were found. There were only 6 volatiles with different contents in the pork tenderloin (P < 0.05). Moreover, there were no oxidized cysteine and methionine residues in myosin of thawed pork by HVEF. A total of 23 discriminating metabolites between the air-thawed and HVEF-thawed pork after orthogonal partial least squares-discriminate analysis (OPLS-DA). There were 10 pathways containing >5 discriminating metabolites, among them, there were 10 discriminating metabolites in the glycerophospholipid metabolism (ssc00564) and retrograde endocannabinoid signaling (ssc04723). The glycerophospholipid metabolism could be related to the pork spoilage processes.

Pulsed Electric Fields-Modified Ferritin Realizes Loading of Rutin by a Moderate pH Transition

Ferritin shares a conserved 24-subunit spherical structure and a unique reversible self-assembly characteristic. In the present work, pulsed electric fields (PEF) technology was used to treat red bean seed ferritin deprived of iron (apoRBF) to fabricate a PEF-modified apoRBF (PEFF). Results indicated that PEF treatment at 20 kV/cm for 7.05 ms retained the spherical structure but decreased the α-helix/β-sheet contents of ferritin. Differential scanning calorimetry (DSC) and UV-vis analyses proved that the thermal stability of the PEFF was decreased. Consequently, PEFF disassembled at pH 3.6 and reassembled when the pH was restored to 7.0, exhibiting a more moderate condition relevant to the traditional approach. Using the pH 3.6/7.0 transition routine, rutin molecules were successfully loaded within PEFF nanoparticle. The rutin-loaded PEFF showed a diameter of 12 nm with an encapsulation ratio of 13.7% (w/w). Moreover, PEFF played a role in protecting the encapsulated rutin molecules upon thermal treatment (20-70 °C). This work will be beneficial for extension of PEF application in protein modification and will improve ferritin functionalization as a carrier for food bioactive molecules by a moderate pH transition method.

Fundamental interfacial mechanisms underlying electrofreezing

This article reviews the fundamental interfacial mechanisms underlying electrofreezing (promotion of ice nucleation via the application of an electric field). Electrofreezing has been an active research topic for many decades, with applications in food preservation, cryopreservation, cryogenics and ice formation. There is substantial literature detailing experimental and simulations-based studies, which aim to understand the complex mechanisms underlying accelerated ice nucleation in the presence of electric fields and electrical charge. This work provides a critical review of all such studies. It is noted that application-focused studies of electrofreezing are excluded from this review; such studies have been previously reviewed in literature. This review focuses only on fundamental studies, which analyze the physical mechanisms underlying electrofreezing. Topics reviewed include experimental studies on electrofreezing (DC and AC electric fields), pyroelectricity-based control of freezing, molecular dynamics simulations of electrofreezing, and thermodynamics-based explanations of electrofreezing. Overall, it is seen that electrofreezing can enable disruptive advancements in the control of liquid-to-solid phase change, and that our current understanding of the underlying mechanisms can be significantly improved through further studies of various interfacial effects coming into play.

Microelectric Current Treatment Enhanced Biodegradation of Pumpkin Lignocelluloses by Trichoderma reesei RUT-C30

A homemade microcurrent reactor was used to treat the fermentation of Trichoderma reesei. Results indicated that the yield of saccharides for T. reesei RUT-C30 cultivated in pumpkin lignocellulose broth reaches 38.86% (w/w) when a microcurrent treatment (20 mA, at the 48th hour for 60 min) was carried out, which is significantly higher than the control group (p < 0.05). Additionally, activities of endoglucanase, cellobiohydrolase, xylanase, and pectinase were significantly increased in days 3-7. Furthermore, the fungal growth was facilitated by microelectric treatment, showing a 0.57-fold increase of spore numbers at the sixth day of cultivation. Besides, the monosaccharide composition, including glucose (1.03 mg/mL), xylose (0.12 mg/mL), arabinose (0.31 mg/mL), and fructose (0.13 mg/mL), extracted from the reactor was higher than that without the current treatment. In this work, we improved the biodegradation of lignocellulosic wastes by applying a microcurrent to lignocellulose-degrading fungal cultures and provided a new idea for the lignocellulose material pretreatment and bioconversion.

The Thawing Characteristic of Frozen Tofu under High-Voltage Alternating Electric Field

To systematically and comprehensively investigate the high voltage alternating electric field (HVAEF) thawing processing, we investigated the high-voltage electric field thawing characteristic of the frozen tofu at different voltages for alternating current (AC). The thawing time, thawing loss of frozen tofu, and specific energy consumption (SEC) of HVEF system were measured. Seven different mathematical models were then compared to simulate thawing time curves based on root mean square error, reduced mean square of deviation, and modeling efficiency. The results showed that the thawing rate of frozen tofu was notably greater in the high-voltage electric field system when compared to control. Both Linear and Quadratic models were the best mathematical models. Therefore, this work presents a facile and effective strategy for experimentally and theoretically determining the HVAEF thawing properties of frozen tofu.