Search Results (646)

Municipal sewage sludge is an environmental liability but also an energy-rich biomass that can support circular economy resource recovery. Here, we benchmark thin-layer drying of dewatered municipal sewage sludge (sludge cake) (40 g; layer thickness ≤ 5 mm) under open-air, convective hot air (40–150 °C), and microwave (70–1200 W) conditions to quantify drying kinetics, hygienisation indicators, and a screening-level energy-use proxy. High-power microwave drying reduced the time to constant mass from 32 h (open air) and 25 h 05 min (40 °C convection) to 20 min (900 W) and 14 min 05 s (1200 W). Faecal indicators (total/thermotolerant coliforms and presumptive Escherichia coli) were below detection after ≥100 °C convection or ≥300 W microwave treatment, while mesophilic aerobes and sulfite-reducing Clostridium spp. decreased by ~3–4 log10 with increasing exposure. A dragonfly-optimised ε-support vector regression model (DA–SVR) predicted drying trajectories across modes (overall RMSE ≈ 0.79 percentage points; held-out RMSE ≈ 1.47; R² ≥ 0.99). Overall, microwave thin-layer drying coupled with DA–SVR decision support enables constraint-based screening of sewage–sludge conditioning windows for logistics and thermal valorisation pathways; the framework can be extended to incorporate additional analytical endpoints where available. Full article

This study investigated the effects of black chokeberry (Aronia melanocarpa) (Michx.) Elliott powder addition (0.1–0.4%) on the quality attributes of cheese snacks produced from a blended camel–goat–cow milk base (60:20:20) using microwave vacuum drying. The snacks were evaluated for chemical composition, colour parameters, texture profile and water activity in order to assess how black chokeberry incorporation influences their physicochemical and sensory-related properties. Chemical analysis showed that the high protein content of the dried cheese matrix was maintained across all formulations, while fat, carbohydrate and energy values varied within a relatively narrow range, without a clear dose-dependent trend attributable solely to black chokeberry addition. Black chokeberry powder induced concentration-dependent colour changes, with decreased lightness and increased redness and overall colour difference, indicating visually noticeable shifts that may enhance product differentiation. Texture profile analysis revealed a significant reduction in fracturability at intermediate inclusion levels, suggesting a less brittle structure, whereas other texture parameters showed non-linear but statistically non-significant variations due to limited replication. All snacks exhibited very low water activity, consistent with shelf-stable, low-moisture products. A preliminary sensory test with untrained assessors indicated that black chokeberry-enriched snacks, particularly at around 0.3%, were generally well accepted, although the small panel size limits the strength of these conclusions. Overall, the findings suggest that small additions of black chokeberry powder can be used to develop visually attractive, high-protein cheese snacks with promising textural and sensory characteristics, while more comprehensive studies are needed to characterise their antioxidant properties, detailed nutritional profile and long-term stability. Full article

This study evaluates the impact of four drying methods—open sun drying, solar drying, infrared drying, and microwave drying—on the quality attributes and elemental retention of apricots (Prunus armeniaca L.). Experimental trials were conducted in June 2024 at the Tashkent Institute of Chemical-Technology using equal quantities of fresh apricots. Drying was continued until the moisture content, measured gravimetrically, dropped below 20% (wet basis), followed by spectroscopic analysis to determine macro- and microelement concentrations. Solar-dried apricots showed higher retention of essential nutrients in this experimental trial: potassium (2.37%), silicon (0.538%), magnesium (0.145%), calcium (0.176%), and sulfur (0.152%). In contrast, open sun drying led to significant nutrient degradation and poor visual quality. Microwave drying preserved some micronutrients but resulted in surface scorching due to uneven heating. Infrared drying yielded acceptable results but required substantial energy input. Among all methods, solar drying provided the optimal balance of high product quality and energy efficiency. The drying process required negligible electrical energy owing to exclusive reliance on solar radiation. This method supports sustainable food processing by reducing energy demand and greenhouse gas emissions while preserving nutritional quality. The results highlight solar drying as a promising, eco-friendly technique for preserving the nutritional integrity of agricultural products. These findings offer valuable scientific guidance for selecting appropriate drying technologies in the food processing industry, especially in regions with high solar potential. However, the study is limited to a single fruit variety and seasonal conditions. Full article

Seafood processing generates large volumes of by-products that are often underutilized despite their potential as sources of high-value bioactive lipids. In this study, a hybrid process integrating microwave (MW) pretreatment with Soxhlet (SOX) extraction was developed and optimized to intensify the recovery of astaxanthin (ASX)- and ω-3 PUFA-rich oil from green tiger shrimp (Penaeus semisulcatus) residues. Response surface methodology (RSM) comprising 22 experimental runs was applied to optimize key MW process variables, including power (100–400 W) and irradiation time (30–90 s). Both factors significantly influenced oil yield, with optimal operating conditions identified at 400 W and 75 s. MW pretreatment promoted structural disruption of shrimp shells, as confirmed by scanning electron microscopy, thereby enhancing solvent penetration and mass transfer. Solvent selection further affected extraction performance: hexane:isopropanol (1:1, v/v) achieved the highest oil yield (3.86 g/100 g dry weight), while hexane:acetone produced extracts with the highest ASX concentration (1032.24 µg/g oil), ω-3 PUFA content (29.85%), and antioxidant activity (93.30% DPPH scavenging). Colorimetric analysis supported these results, with increased redness (a* = 18.12) correlating with ASX enrichment. Overall, this integrated MW-SOX process represents an effective process-intensification strategy for sustainable shrimp waste valorization and production of bioactive lipid fractions. Full article

Soil moisture (SM) mediates land–atmosphere water and energy exchanges and is therefore central to evapotranspiration, drought evolution, and hydroclimate extremes. The SM drydown timescale (τ), typically derived from exponential decay fits following rainfall or snowmelt rewetting, provides a compact measure of near-surface “memory” and drying rate. Despite the availability of microwave satellite SM products, their reliability for drydown characterization over the Tibetan Plateau remains uncertain, and systematic evaluations of drydown events and τ against in situ networks are still limited. Here, we integrate five Tibetan Plateau (TP) soil moisture sensor networks with SMAP to (i) assess consistency in drydown event detection and τ estimation across observation systems and (ii) map TP-wide τ patterns and identify dominant controls using SMAP (2016–2025). SMAP-derived τ is generally smaller than in situ τ, indicating a faster drying signal in the satellite product; this may be attributed to differences in effective sensing depth and spatial representativeness between satellite footprints and point measurements. TP SMAP τ exhibits a pronounced southeast-to-northwest decreasing gradient, with the shortest τ over the arid interior. Partial least squares regression identifies elevation, sand fraction, and vegetation conditions as primary drivers of spatial τ variability. This research provides observational constraints for understanding land-surface hydrological processes and land–atmosphere coupling in alpine regions. Full article

Radish leaves are a nutrient-rich yet underutilized byproduct containing abundant fiber, minerals, and phytochemicals; however, their quality is highly affected by drying methods. This study systematically investigated the effects of three drying methods—hot-air drying (HD), microwave drying (MD), and freeze-vacuum drying (FD)—on the nutritional components, bioactive substances, and volatile compounds of radish leaves. A comparative analysis was conducted on their proximate composition, amino acid profiles, mineral contents, antioxidant capacities, glucosinolate profiles, and volatile profiles. Among the three methods, FD exhibited superior preservation of proteins, lipids, minerals (K, Mg, P, Fe, Zn, and Mn), and bioactive components, including polyphenols, flavonoids, glucosinolates, and vitamin C. In contrast, HD and MD led to significant reductions in these nutrients and bioactive compounds. A total of 33 glucosinolates and 779 volatile compounds, including 164 odor-active compounds, were identified collectively across the three treatments. The FD-treated samples exhibited distinct glucosinolate and volatile profiles, whereas HD- and MD-treated samples showed greater similarity. Multivariate analysis further revealed 12 key differential glucosinolates and 27 differential odor-active compounds among the three groups. This study provides a scientific basis for optimizing drying strategies to improve the nutritional quality and flavor characteristics of processed radish leaves. Full article

Dill is a valuable herb recognized for its rich nutritional composition and bioactive properties. Drying is an efficient preservation technique for maintaining its quality characteristics and ensuring longer storage stability. Incorporating ultrasonic pretreatment before the drying process can significantly reduce energy consumption (SEC) and greenhouse gas emissions. To the best of our knowledge, this is the first study to comprehensively evaluate ultrasound-assisted hybrid microwave–convective drying of dill (Anethum graveolens L.) leaves, focusing on the combined effects on drying kinetics, energetic and exergetic performance, providing an indirect emission estimate and multiple quality attributes. This study aimed to evaluate the drying kinetics, energy and exergy performance parameters, greenhouse gas emissions, quality properties (water activity, rehydration ratio and color) and antioxidant capacity of dill leaves dried by the microwave–hot-air (MW-HA) technique combined with ultrasonic (US) pretreatment. The experiments were conducted at MW power levels of 20%, 40%, and 60% (corresponding to a total output of 900 W), air temperatures of 40 and 60 °C, and US pretreatment durations of 0, 10, and 30 min. The results illustrated that rising MW power, air temperature and US duration significantly reduced the drying time, SEC and greenhouse gas emissions. At higher process conditions, specifically, 40% MW power, 60 °C drying temperature, and 30 min US pretreatment, the maximum energy efficiency (10.17%) and exergy efficiency (11.35%) were obtained. In terms of quality attributes, the best results were achieved at 40% MW power, 60 °C air temperature, and 10 min ultrasonic pretreatment, with reduced water activity (0.258), minimal color variation (ΔE = 11.44), improved rehydration ratio (3.88), and high retention of antioxidant activity. These findings demonstrate the potential of ultrasound pretreatment to enhance drying performance by reducing energy use and emissions while improving quality and antioxidant retention in dill, offering new guidelines for sustainable processing of this herb. Future studies should optimize microwave–hot-air-drying conditions to balance energy efficiency, exergy, and product quality. Full article

Blackthorn (Prunus spinosa L.) is an underutilized Mediterranean wild fruit recognized as a valuable source of bioactive phenolic compounds with potential applications in food and nutraceutical formulations. Despite growing interest in sustainable extraction approaches, systematic comparisons of green extraction technologies for blackthorn phenolic recovery remain limited, particularly for North African ecotypes. In this study, four non-conventional green extraction techniques, pressurized liquid extraction, microwave-assisted extraction, ultrasound-assisted extraction, and Ultra-Turrax-assisted extraction, were compared for the recovery of phenolic compounds from Algerian blackthorn fruits under method-specific controlled conditions. Total phenolic compounds, flavonoids, anthocyanins, and condensed tannins were quantified, together with antioxidant capacity evaluated using multiple complementary assays. Pressurized liquid extraction yielded the highest total phenolic compound content (21.89 mg gallic acid equivalents/g dry weight) and flavonoid content (8.18 mg catechin equivalents/g dry weight), while microwave-assisted extraction showed the highest anthocyanin recovery (3.19 mg cyanidin-3-glucoside equivalents/g dry weight). Antioxidant capacity values obtained by different assays showed comparable trends for pressurized liquid extraction and microwave-assisted extraction. The extract obtained by the most effective method was further evaluated for antimicrobial activity, showing selective inhibitory effects against methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, and Bacillus subtilis. Chemical characterization by liquid chromatography–tandem mass spectrometry revealed a profile dominated by flavonoids, mainly quercetin derivatives, and hydroxycinnamic acids. Overall, these findings highlight pressurized liquid extraction as a promising green technology for the valorization of blackthorn fruits as sources of phenolic compounds for food-related applications. Full article

This study systematically evaluated the drying kinetics of Zanthoxylum bungeanum Maxim. during microwave vacuum drying (MVD), pulsation vacuum drying (PVD) and hot-air drying (HAD) at different temperatures and analyzed the heating mechanism differences in the three technologies via numerical simulation. Drying kinetics indicated that MVD was the most efficient technique owing to its volumetric dielectric heating, whereas the PVD efficiency depended heavily on precise cyclic parameter control. As verified by simulations, a more uniform temperature field was formed in MVD, while PVD achieved focused core heating via infrared radiation. Quality analysis revealed that the dehiscence rate increased significantly with the temperature, and both MVD and PVD demonstrated superior color retention over HAD; however, MVD was the most effective for preserving volatile oils, while PVD excelled in amide preservation. It should be noted that the specific component retention advantages of PVD were balanced by its strict parameter requirements, which limits its potential for large-scale application. Comprehensive evaluation confirmed MVD’s superiority in Z. bungeanum drying, effectively retaining thermosensitive components under a vacuum pressure of −90 kPa at 60 °C. Full article

Soil moisture is an essential climate variable exhibiting strong spatio-temporal dynamics, especially in the topsoil. Therefore, it is assessed multiple times by sensors within in situ networks, satellites, and by modeling of the Earth system. The resulting soil moisture fields from all methods are individual and non-congruent due to the imperfection of the methods and retrievals. But their spatial patterns have valuable similarities that call for investigation to foster intercomparison or even fusion of soil moisture products. In this research study, the similarity of spatial soil moisture patterns between passive microwave remote sensing products and Earth system modeling is investigated. We configure and apply spatial similarity metrics to enable a spatial comparison of the operational SMAP Dual Channel Algorithm (DCA) radiometer soil moisture product with the soil moisture output from IFS model runs of the ECMWF. The pattern assessment spans over the whole of Europe and aims to find the drivers behind the spatial soil moisture distributions at scales ranging from single grid cells (minimum) to continental (maximum) spatial scales, and between growing periods of wet (2021) and dry (2022) years. The two specifically configured metrics, total disagreement and mean category distance, showcase the opportunities and challenges when assessing spatial similarity in soil moisture fields across different scales. In addition, the potential drivers of the spatial moisture patterns were screened. Here, soil texture is the most influential single driver of spatial patterns in the IFS soil moisture runs, when analyzed in absolute terms [m³ m⁻³]. In relative terms of soil moisture [-] (soil wetness index), precipitation and soil temperature explain most of the variability of the IFS soil moisture for Europe. The SMAP retrievals are predominantly driven by the brightness temperatures, mostly influenced by surface temperature, vegetation water content, and soil roughness. These differences in drivers, as well as in methodology, culminate in an inherent discrepancy between the two soil moisture products. However, the assessment of their spatial patterns reveals the underlying similarity from the local to the continental scale. Full article

This study investigates the elaboration, structural characteristics, and antibacterial performance of silver-based nanoparticles obtained via a hydrolytic chemical route, with and without assistance from ultrasound and microwave irradiation. Two silver nitrate precursor concentrations (1 M and 2 M) were employed to evaluate the influence of synthesis conditions on phase composition, morphology, and antimicrobial efficiency. The obtained powders were characterized by ATR-FTIR, X-ray diffraction (XRD), and scanning electron microscopy (SEM). XRD analysis revealed that drying at 120 °C led to oxide-rich systems dominated by Ag₂O, with minor contributions from metallic Ag and carbonate species, while calcination at 550 °C resulted in complete phase transformation into highly crystalline metallic silver. SEM observations demonstrated that precursor concentration and synthesis assistance strongly affect particle size, aggregation degree, and surface morphology. Ultrasound- and microwave-assisted synthesis promoted finer crystallite sizes and more homogeneous particle distributions compared to non-assisted routes. The antibacterial activity was evaluated against Escherichia coli (Gram-negative) and Clostridium perfringens (Gram-positive, anaerobic, spore-forming). Oxide-rich samples, particularly Ox.Ag/2 M, exhibited rapid and complete bacterial inactivation within 30 min, while metallic silver samples showed time-dependent antibacterial behavior, achieving full inhibition after 4 h. The results demonstrate that antibacterial efficiency is governed by a synergistic interplay between silver oxidation state, nanoscale morphology, and surface reactivity. These findings highlight the potential of tailored silver-based nanomaterials as effective antibacterial materials for biomedical, food safety, and environmental applications. Full article

Considering the demand for nutritional assessment and product quality control in the tea industry, this work develops an effective electrochemical sensor based on gold nanoparticles electrodeposited onto a zeolitic imidazolate framework (Au/MOF(Zn)) for evaluating the antioxidant activity of tea subjected to microwave-assisted drying (MAD) through hydrogen peroxide (H₂O₂) scavenging. The MOF(Zn) enables uniform deposition of AuNPs, which significantly enhances the electrocatalytic oxidation of H₂O₂. The fabricated sensor exhibits a wide linear detection range from 400 μM to 1.8 mM for H₂O₂ with a correlation coefficient of 0.9983. The experimental results demonstrate acceptable selectivity, with signal interference <5% from common tea compounds like inorganic ions, sugars, and organic acids. Electrochemical methods, including cyclic voltammetry (CV) and differential pulse voltammetry (DPV) analysis, were employed to quantify H₂O₂ by measuring oxidation currents in phosphate-buffered saline (PBS, pH 7.0). The relative standard deviation (RSD) for repeatability and reproducibility was 5.1% and 6.8%, respectively, confirming high reliability. This sensor was successfully applied to assess antioxidant capacity in tea extracts obtained from fresh leaves subjected to microwave-assisted drying under varying power and duration. Results indicate that increasing microwave power enhances antioxidant activity, while prolonged drying at low power initially increases activity (peaking at 120 s) but reduces it upon extended exposure. Optimal antioxidant preservation was achieved at 120 s. This real-time, reliable sensing strategy offers theoretical foundations for optimizing tea processing parameters to preserve bioactive compounds, particularly polyphenols like catechins, thereby improving tea quality and health benefits. Full article

Olive leaves, a by-product of the olive oil industry, represent an interesting underutilized raw material for the preparation of herbal teas. However, processing conditions, particularly drying methods, may strongly influence their chemical and sensory quality. This study aimed to evaluate the effect of air drying (AD) and microwave drying (MWD) on the phenolic content, antioxidant capacity, volatile aroma compounds, sensory profile, and consumers’ acceptability of olive leaf herbal teas. Olive leaves were subjected to AD (50 °C, 3 h) and MWD (400 W, 4 min), and infusions were prepared. Total phenolic content (TPC) and antioxidant capacity (AC) were evaluated spectrophotometrically, volatile compounds were analyzed by HS-SPME-GC-MS, and sensory characteristics were assessed through descriptive sensory analysis and consumers’ acceptability test. MWD significantly increased TPC compared to AD; however, this increase was not proportionally reflected in AC. The drying methods influenced the volatile profile of herbal teas, with AD showing a higher amount of alcohols, esters, and terpenes associated with green and floral notes, whereas MWD showed a major content of aldehydes and ketones linked to fruity notes. Sensory analysis confirmed these differences; moreover, MWD herbal teas were more bitter and astringent, and consumer tests showed a clear preference for herbal teas produced from AD leaves. Overall, the results highlight the key role of drying methods in shaping the chemical and sensory attributes of olive leaf herbal tea, suggesting air drying to be the most suitable process for producing a sensorially acceptable product. Full article

The growing volume of decommissioned wind turbine blades, primarily made of glass fibre-reinforced polymers (GFRP), poses major recycling challenges. This study explores a microwave (MW)-assisted thermochemical recycling to recover high-quality fibres from GFRP waste. Two routes were evaluated: (i) a dry route using direct MW heating, and (ii) a semi-wet route involving solvent pre-swelling followed by microwave pyrolysis. The dry route suffered from poor heating due to GFRP’s inherently low dielectric loss, whereas the semi-wet route enabled more effective resin degradation. Five swelling agents were tested: acetic acid (AcOH), hydrogen peroxide (H₂O₂), an AcOH/H₂O₂ mixture, dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). Among these, DMSO achieved 92% resin removal in 9 min at 350 °C. Recycled fibres retained 1.48 ± 0.41 GPa strength (81% of virgin). Gas chromatography–mass spectrometry (GC–MS) analysis of pyrolysis oils revealed predominantly phenolic products with limited bisphenol A (BPA) retention. To demonstrate practical relevance, the semi-wet method was applied to real wind blade waste, where recovered fibres retained 72% of their tensile strength versus virgin fibres. These results indicate that the process remains effective for industrially aged GFRP. This study confirms the feasibility of MW-based semi-wet recycling and offers insights to support future process refinement, which will ultimately contribute to more sustainable end-of-life solutions for GFRP waste. Full article

Brief treatment of a bottled young dry red wine with low-intensity natural emissions in the mid-infrared and far-infrared/near-microwave regions of the electromagnetic spectrum resulted in moderate changes in the concentrations of certain odorants in the wine headspace (vapor), as shown by headspace–solid-phase microextraction–gas chromatography/mass spectrometry (HS-SPME-GC/MS). The headspace levels of certain long-chain ethyl carboxylate esters and methyl salicylate were somewhat enhanced, whereas those of certain aromatic monohydric alcohols, a succinate ester, and oak lactone were somewhat depleted. A tentative explanation of these results is offered whereby waveform treatment results in general re-organization of non-covalent associations of both odorant (volatile) and non-volatile components in wine, leading to the preferential extra release of certain odorants into the headspace (vapor phase) and preferential increased trapping of certain other odorants in wine (liquid phase). Full article