Current Issue : April-June Volume : 2025 Issue Number : 2 Articles : 5 Articles
The widespread popularity of pasta has driven innovations in formulations and production technologies to enhance its versatility. Techniques such as alternative drying methods and fortification of wheat pasta seek to improve the nutritional value and functional properties of pasta products, thereby increasing their attractiveness to consumers. This study aimed to evaluate the effects of microwave–vacuum drying versus conventional drying on the characteristics of durum wheat semolina pasta, including moisture content, water activity, microstructure, colour, texture, weight gain factor, and cooking loss. Three types of pea protein concentrates (80, 84, and 88% dry matter) were used at levels of 3, 6, and 9% (g/100 g flour). Results indicated that microwave–vacuum drying had a significant impact on the physical properties and cooking quality of pasta. Microwave–vacuum drying caused material puffing, resulting in microstructure with high open porosity (64.1%) and minimal closed porosity (0.1%). This has likely contributed to the short rehydration time (2 min in boiling water) of produced pasta, effectively transforming it into an instant food product. All pasta samples had low water content (<9%) and water activity (<0.4), which ensure food safety. The microwave–vacuum-dried pasta weight gain factor (2.2) was lower than in the conventionally dried pasta (2.8). The firmness of microwave–vacuum-dried pasta was significantly higher (135 g) than that of conventional pasta (16 g). Fortification with pea protein enhanced porosity but did not affect pasta’s culinary parameters, such as weight gain or cooking loss, although it resulted in darker pasta (p = 0.001), especially notable with a 9% pea protein addition....
The complex dielectric permittivity, ε (f, H) = ε′ (f, H) − i ε′′ (f, H), in the microwave frequency range f, of (0.1–3) GHz and polarizing field values H, in the range of (0–135) kA/m, was measured for a kerosene-based ferrofluid with magnetite particles. A relaxation process attributed to interfacial type relaxation was highlighted, determining for the first time in the microwave field, the activation energy of the dielectric relaxation process in the presence of the magnetic field, EA(H), in relation to the activation energy in zero field, EA(H = 0). Based on the complex permittivity measurements and the Claussius–Mossotti equation, the dependencies on frequency (f ), and magnetic field (H), of the polarizability (α) and electrical conductivity (σ), were determined. From the dependence of α(f,H), the electric dipolar moment, p, of the particles in the ferrofluid, was determined. The conductivity spectrum, σ(f,H), was found to be in agreement with Jonscher’s universal law and the electrical conduction mechanism in the ferrofluid was explained using both Mott’s VRH (variable range hopping) model and CBH (correlated barrier hopping) model. Based on these models and conductivity measurements, the hopping distance, Rh, of the charge carriers and the maximum barrier height, Wm, for the investigated ferrofluid was determined for the first time in the microwave field. Knowledge of these electrical properties of the ferrofluid in the microwave field is useful for explaining the mechanisms of polarization and control of electrical conductivity with an external magnetic field, in order to use ferrofluids in various technological applications in microwave field....
Carbon dots (C-Dots) have garnered significant attention in various fields, including biomedical applications, photocatalysis, sensing, and optoelectronics, due to their high luminescence, biocompatibility, and ease of functionalization. However, concerns regarding their potential toxicity persist. Conventional synthesis methods for C-Dots often require long reaction times, high pressures, expensive equipment, extreme temperatures, and toxic reagents. In contrast, microwave irradiation provides a rapid, cost-effective, and scalable alternative for the synthesis of high-quality C-Dots. In this study, we report the single-step, 3-min synthesis of water-stable carbon dots at 100 ◦C, 120 ◦C, and 140 ◦C using microwave irradiation. Particle stability was achieved through polyethyleneimine (PEI) functionalization. The toxicity of the synthesized carbon dots was evaluated in marine crustaceans, revealing that C-Dots with an estimated size below 10 nm did not exhibit toxicity after 24 and 48 h of exposure. These findings demonstrate the potential of microwave-synthesized carbon dots as non-toxic, water-stable nanomaterials for environmental and biomedical applications....
Aiming at problems such as low energy utilization efficiency and the high oxygen content of liquid products in the process of conventional biomass conversion to prepare liquid fuels, the deoxygenation pyrolysis technology route of larch based on microwave heating was proposed in this paper. Two kinds of calcium–iron composite oxygen carriers, including Ca2Fe2O5 with iron ore structure and CaFe2O4 with spinel structure, were successfully synthesized. The results showed that the selectivity of ideal products was improved under the action of single iron-based oxygen carriers; however, the deoxygenation effect was undesirable. Under the action of CaFe2O4, the selectivity of aromatics was increased to 27.17% and the selectivity of phenols was decreased to 36.46%, which mainly existed in the form of O1P with low oxygen content. The oxygen content of bio-oil was reduced to 27.70% and the calorific value was increased to 29.05 MJ/kg, thus leading to a great improvement in the quality of liquid products. After the pyrolysis reaction, the Fe2P3/2 XPS peak of CaFe2O4 shifted to a higher binding energy and was characterized as higher valence of iron oxide, which proved its “oxygen grabbing” capacity in microwave pyrolysis. The deoxygenation conversion of larch without an external hydrogen supply was achieved....
This study presents a sustainable solution for the removal of the emerging contaminant chloroquine from aqueous solutions, utilizing biochar synthesized from cassava waste through a rapid, single-step microwave activation process. By repurposing cassava waste, a prevalent agricultural by-product, this method aligns with circular economy principles, promoting the sustainable reuse of waste materials. Characterization of the biochar demonstrated a highly porous, crystalline structure optimized for adsorption applications. Adsorption studies demonstrated optimal performance at 45 ◦C, with a maximum adsorption capacity of 39 mg g−1 in the Langmuir model. Thermodynamic analysis confirmed that the process was spontaneous, endothermic, and consistent with physisorption. Kinetic experiments revealed that 200 rpm agitation provided the most favorable conditions. Notably, the biochar demonstrated substantial reusability, maintaining up to 70% of its adsorption capacity over five desorption cycles. This sustainable adsorbent stands out as a practical, eco-friendly option for removing pharmaceutical contaminants while also corroborating with the beneficial reuse of agricultural by-products....
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