Search Results (153)

Solid-state fermentation (SSF) involves the growth of microorganisms on solid substrates, mimicking natural environments of many species. Due to sustainability concerns, transforming agro-industrial by-products into value-added products through SSF has been increasingly studied. Brewer’s spent grain (BSG), the main by-product of beer production, mostly consists of barley grain husks, making BSG a great support for microorganism cultivation. Although autoclaving remains the standard sterilization and pretreatment method of substrates, electric field technologies and their attendant ohmic heating (OH) have great potential as an alternative technology. In the present work, pretreatment of BSG by OH was explored in SSF with Aspergillus niger to produce commercially valuable enzymes. OH favored the solubilization of phenolic compounds, total protein, and reducing sugars significantly higher than autoclaving. SSF of treated BSG led to the production of lignocellulosic enzymes, with xylanases being the most active, reaching 540 U/g, a 1.5-fold increase in activity compared to autoclaved BSG. Protease activity was also improved 1.6-fold by OH, resulting in 49 U/g. Our findings suggest that OH treatment is an effective alternative to autoclaving and that its integration with SSF is a sustainable strategy to enhance by-product valorization through enzyme production with many industrial applications, according to circular economy guidelines. Full article

Overheating and overcharging are the core triggering conditions for the thermal runaway of lithium-ion batteries. Studying the behavioral differences of thermal runaway of lithium-ion batteries under these two conditions is crucial for the safety design and protection of lithium-ion batteries. In this study, we investigated the temperature, pressure, gas generation, and heat generation characteristics of lithium batteries under these two conditions. Under overheating conditions, the release of lattice oxygen in the cathode and the decomposition of the electrolyte trigger a self-catalytic reaction, generating CO₂ (54.7%) and H₂ (29.7%), with a total heat release of 17.6 kJ and a heat accumulation rate of 24.3 W, forming a local high-temperature core area. Under overcharging conditions, the voltage drop, capacity attenuation of 21.1% (2230→1762 mAh), and internal resistance surge (6→21 mΩ) reflect severe damage to the electrode. Accompanied by the oxygenation of the EC electrolyte (CO₃²⁻ + C₂H₄↑), the gas production rate is faster. The middle pressure was 0.601 MPa, and the proportion of CO₂ was 67.4%. However, the triggering of thermal runaway relies on the synergistic effect of internal electrochemical reactions and ohmic heat accumulation, resulting in a relatively low rate of energy accumulation. Full article

An analysis of entropy generation and a performance comparison are carried out for a solid oxide fuel cell with an embedded porous pipe in the air supply channel of a mono-block-layer-build geometry (MOLB-PPA SOFC) and a planar geometry with trapezoidal baffles inside the fuel and air channels (P-TBFA SOFC). The results for power density at different current densities are discussed. Also, a comparison of the field of species concentration, temperature, and current density on the electrode–electrolyte interface is analyzed at a defined power density. Finally, a comparison of maps of the local entropy generation rate and the global entropy generation due to heat transfer, fluid flow, mass transfer, activation loss, and ohmic loss are studied. The results show that the MOLB-PPA SOFC reaches a 7.5% higher power density than the P-TBFA SOFC. Furthermore, the P-TBFA SOFC has a more homogeneous temperature distribution than the MOLB-type SOFC. The entropy generation analysis indicates that the MOLB-PPA SOFC exhibits lower global entropy generation due to heat transfer compared to the P-TBFA SOFC. The entropy generation due to ohmic losses is predominant for both geometries. Finally, the total irreversibilities are 24.75% higher in the P-TBFA SOFC than in the MOLB-PPA SOFC. Full article

Fresh-cut potatoes are highly perishable, requiring effective preservation strategies to maintain quality and extend shelf life. This study evaluated the use of edible coatings and the combination of osmotic dehydration and ohmic heating (OH-OD), both integrated with modified atmosphere packaging (MAP), to enhance microbial stability and reduce quality deterioration. Key quality parameters—including color stability, browning index, weight loss, microbial activity, and sensory attributes—were assessed. Results showed that coated samples (E-FP) had the lowest browning index (59.71) by day 8, compared to a value of 62.69 in control samples (C-FP). OH-OD-treated samples exhibited the least weight loss (6.73%) versus 17.75% in C-FP. Microbial analysis showed that E-FP samples maintained the lowest total viable count by day 8 (3.98 ± 0.02 log CFU/g), compared to OH-OD-FP (4.43 ± 0.13 log CFU/g) and C-FP (4.79 ± 0.06 log CFU/g), confirming the antimicrobial efficacy of the edible coating enriched with rosemary essential oil and ascorbic acid. Sensory evaluation further confirmed that coated samples retained superior sensory qualities, receiving the highest overall acceptance score of 8.86 ± 0.80, compared to values of 7.80 ± 0.98 for control samples (C-FP) and 2.80 ± 0.69 for OH-OD-FP samples, highlighting their enhanced consumer appeal. These findings highlight that combining advanced preservation techniques with MAP can significantly reduce moisture loss and microbial spoilage while maintaining freshness and sensory appeal. This integrated approach offers a promising solution for extending shelf life, reducing food waste, and supporting sustainability in response to consumer demand for minimally processed, high-quality fresh products. Full article

Rich in bioactive compounds, pigmented rice offers superior antioxidant capacity compared to non-pigmented rice. Processing methods like milling, parboiling, thermal treatments (e.g., extrusion cooking), and biobased approaches (e.g., germination and fermentation) impact the technological and nutritional properties of pigmented rice. All products with added pigmented rice showed improved total phenolic content and antioxidant capacities. Extrusion cooking improved technological properties of dough, bread, and bakery products by modifying the pasting properties of rice. Germination and fermentation enhanced bakery products’ nutritional value by increasing gamma-aminobutyric acid (GABA) levels. Pigmented rice flour can enhance the volume, crumb firmness, and elasticity of gluten-free (GF) bread, especially with ohmic heating. It improved sensory qualities and consumer acceptance of various baked products and extruded snacks. While pigmented rice-based pasta and noodles had compromised cooking qualities, germination improved noodle cooking qualities. Pre-processing techniques like parboiling and micronisation show potential for improving pigmented rice’s technological properties and warrant further study. In conclusion, pigmented rice can enhance the technological and nutritional qualities of bread, bakery products, and snacks. Future researches should focus on agronomic advancement, optimization of pre-processing and processing techniques, exploring varietal differences among pigmented rice cultivars, and promotion of consumer awareness and market potentials. Full article

The proton exchange membrane electrolyzer (PEMWE) has been regarded as a promising technology for converting surplus intermittent renewable energy into green hydrogen through electrochemical water splitting. However, the multiphase mass and charge transport processes with countercurrent flow within the PEMWE create complex structure–property relationships that are difficult to optimize. The interdependent effects of multiple structural parameters on the coupled heat transfer, mass transfer, and charge transfer processes further obscure performance optimization mechanisms. To decouple these phenomena and elucidate the underlying mechanisms, a multiphase one-dimensional mathematical model was developed and experimentally validated. Based on the model, the mass transfer, charge conduction, and heat transfer processes inside the PEMWE have been systematically investigated, with a particular focus on the performance-related parameters of the porous transport layer (PTL). The results reveal that PTL thickness and porosity exhibit opposite effects on activation and ohmic overpotential at an elevated current density. Furthermore, a sharp performance decline occurs when PTL gas permeability falls below the critical threshold. These findings provide quantitative guidelines for multiphysics-informed component optimization in high-performance PEMWEs. Full article

This review aims to give evidence of the current developments and potential applications of emerging technological methods to improve the technological performance and the sensorial acceptability of wholegrain products. The review explores the technologies based on physical, i.e., micronization, steam explosion, high hydrostatic pressure, extrusion cooking, ohmic heating, and 3D printing, and biotechnological methods, such as fermentation and enzymatic treatments in the pre-milling, milling, and transformation steps of wholegrain products. The literature from the past decade for this review article was collected from electronic databases such as ScienceDirect, PubMed, Google Scholar, and Web of Science. Full article

This study employed ohmic heating to investigate its impact on the physicochemical properties, structural organization, and functional characteristics of okara. Ohmic heating was applied with different field strengths and holding times. After moderate ohmic treatment, the water-holding capacity, oil-holding capacity, and swelling capacity of okara increased by 51.11%, 88.89%, and 43.64%, respectively. The microstructure and secondary structure were improved. The total sugar and soluble dietary fiber content were enhanced. The levels of active substances such as total flavonoids and total phenols significantly increased, leading to improved antioxidant capacity. The properties of okara were influenced by the field strength and holding time. This study provides new insights for the processing and development of okara, particularly in the application of functional foods. Full article

Textile structures with ohmic (Joule) heating capability are frequently used for personal thermal management by tuning fluctuations in human body temperature that arise due to climatic changes or for medical applications as electrotherapy. They are constructed from electrically conductive textile structures prepared in different ways, e.g., from metallic yarns, conductive polymers, conductive coatings, etc. In comparison with other types of flexible ohmic heaters, these structures should be corrosion resistant, air permeable, and comfortable. They should not loose ohmic heating efficiency due to frequent intensive washing and maintenance. In this study, the basic electrical properties of a conductive fabric composed of a polyester/cotton fiber mixture and a small amount of fine stainless-steel staple fibers (SS) were evaluated and predicted. Even though the basic conductive component of SS fibers is iron and its electrical characteristics obey Ohm’s law, the electrical behavior of the prepared fabric was highly nonlinear, resembling a more complex response than that of a classical conductor. The non-linear behavior was probably due to non-ideal, poorly defined random interfaces between individual short SS fibers. A significant time–dynamics relationship was also shown. Using the Stefan–Boltzmann law describing radiation power, we demonstrated that it is possible to predict surface temperature due to the ohmic heating of a fabric related to the input electrical power. Significant local temperature variations in the heated hybrid fabric in both main directions (warp and weft) were identified. Full article

The aim of this review is to provide a comprehensive overview of protein extraction from legume sources, with a focus on both conventional and emerging techniques. Particular attention is given to the impact of innovative methods on protein functionality, a key factor for food applications. Due to their nutritional profile and techno-functional properties, legumes are increasingly regarded as promising alternatives to animal-based protein sources in the food industry. Traditional extraction methods, such as alkaline and acidic extraction, are discussed and compared with novel approaches including enzymatic extraction, ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), ohmic heating (OH), subcritical water extraction (SWE), deep eutectic solvents (DES), and dry fractionation. The potential of these emerging technologies to improve protein yield and functionality is critically assessed, alongside key challenges such as scalability, cost-effectiveness, and potential allergenicity. This review also identifies current research gaps and highlights opportunities for innovation in sustainable protein extraction. Therefore, this review contributes to the development of more efficient, functional, and sustainable protein ingredients production, highlighting the role of innovative extraction technologies in shaping the future of plant-based foods. Full article

This study models the electrical conductivity (EC) of passion fruit juice during ohmic heating under voltage gradients of 10, 20, and 30 V/cm, considering temperature (25–85 °C) and total soluble solids (TSS: 11.5, 15.5, and 19.5 °Brix). EC was measured using a laboratory-scale ohmic heating system, and three empirical models were developed using non-linear regression with the Levenberg–Marquardt algorithm. The second-order polynomial model showed the highest accuracy (R² = 0.9974; RMSE = 0.0191; χ² = 0.0112). EC increased with temperature, which enhanced ion mobility and decreased viscosity, while its relationship with TSS was non-linear: EC rose at low to moderate TSS but declined at higher concentrations, attributed to reduced free water and ion solute interactions. The validated model offers a reliable tool for real-time process control in industrial scale pasteurization and evaporation of tropical fruit juices. Full article

The recycling of cable scrap, particularly from discarded electrical wiring, is gaining significant attention due to the rising demand for copper and the need for sustainable management of electronic waste. Traditionally, mechanical and thermal processings have been used to recover copper and plastic from cables. However, these approaches are often energy-intensive, time-consuming, and costly in terms of equipment and labor. In this study, we present a simple and effective method for recovering materials from cable scrap using a domestic microwave oven. Cable pieces (2–2.5 cm long) were exposed to 700 W of microwave irradiation under rotation for 30 s, enabling the rapid and efficient separation of high-quality copper metal from the core wire, and activated carbon from the carbonized plastic sheath. Microwaves facilitate this process through Ohmic heating, which induces electrical resistance in the metal, generating heat that mechanically loosens the metal and carbonized plastic components. The process demonstrates high efficiency, achieving an 80% reduction in energy consumption compared to conventional processings. This fast and energy-efficient method shows strong potential for scaling up to industrial recycling, offering a cost-effective and environmentally friendly way to recover high-quality materials for further use or repurposing. Full article

The thermomechanical effects on aircraft structures in flight are compared between fair weather and a lightning storm based on a model problem, namely, equations of anisothermal unsteady piezoelectromagnetism are solved in the particular case of a parallel-sided slab assuming (i) steady conditions and spatial dependence only on the coordinate orthogonal to the slab; (ii) the displacement vector orthogonal to the slab; (iii) the magnetic field orthogonal to the electric field, with both in the plane parallel to the sides of the slab. The exact analytical solution is obtained in the linear approximation for the displacement vector, electric and magnetic fields and temperature as function of the coordinate normal to the slab, taking into account heating by the Joule effect of Ohmic electric currents and Fourier thermal conduction. These specify the strain and stress tensors, the electric current and the heat flux. The material properties involved include the mass density, dielectric permittivity, magnetic permeability, elastic stiffness tensor, electromagnetic coupling and thermal stress tensors, pyroelectric and pyromagnetic vectors and piezoelectric and piezomagnetic tensors. The analytic results of the theory are simplified assuming (i) isotropic material properties; (ii) a steady state independent of time. The profiles as a function of the coordinate normal to the slab of the electric and magnetic fields, temperature and heat flux and displacement, strain and stress are obtained in these conditions. Full article

Printed electronics (PEs) are rapidly attracting interest, especially in wearable sensors, smart textiles, and IoT devices. Conductive inks, essential for the fabrication of PE, must be highly conductive, cost-effective, biocompatible, easy to prepare, and less viscous. Conductive inks comprise a conducting material (metals like silver, gold, copper, or carbon-based alternatives like graphite, graphene, and carbon nanotubes), a binder, and a solvent. In this work, a water-based graphite conductive ink is developed using graphite as a conductive material, corn starch powder (non-toxic and biodegradable) as a binder, and distilled water as a solvent. Firstly, corn starch powder is added to distilled water, which is heated up to 100 °C and stirred continuously until a homogeneous gel-like mixture is formed. After cooling the mixture, graphite powder is added to it, and it is stirred for an hour at 450 rpm to obtain the ink. To check the conductivity, the ink is brush-painted on a paper substrate with a dimension of 20 mm × 10 mm and the result shows a low ohmic resistance of ~560 Ω, confirming the highly conductive nature of the ink. Additionally, thermogravimetric analysis (TGA) is performed on the prepared ink to evaluate its thermal stability, and a very strong X-ray diffraction (XRD) peak obtained at 2θ° = 26.5426° and a small peak at 2θ° = 54.6145°, along with a few other small peaks, confirms the presence of graphite with corn starch. Thus, this conductive ink can be used for PEs owing to its affordability, biocompatibility, and ease of preparation. Full article

Soybean Trypsin Inhibitors (STIs) in soy-based foods have negative effects on soybean protein digestion and pancreatic health of humans. The inactivation of STIs is a critical unit operation aimed at enhancing the nutritional properties of soy-based foods during processing. This paper reviews the structure of STIs and soybean proteins, as well as the mechanisms of digestion. Various technologies (physical, chemical, biological) have been used to inactivate STIs. Their parameter settings, operating procedures, advantages, and disadvantages are also described. Mechanisms of inactivation of STIs (Kunitz trypsin inhibitor (KTI) and Bowman–Birk inhibitor (BBI)) conformations under different treatments are clarified. In addition, emerging technologies, e.g., Ohmic Heating, Electron Beam Irradiation, Dielectric-Barrier Discharge, and probiotics, have demonstrated great potential to inactivate STIs. We advise that multiple emerging technologies should combine with other unit operating systems to maximize inactivation efficiency. Full article