Search Results (675)

Biobased wood adhesives are essential to reducing the dependence of wood-based panels on petrochemical and formaldehyde-emitting resins. This review critically synthesizes recent progress in lignin-, tannin-, starch-, furan/HMF-, organic acid-, and soy protein-based adhesive systems, with emphasis on chemical reactivity, curing mechanisms, water resistance, processability, and industrial relevance. The discussion distinguishes laboratory performance from industrial feasibility by considering specific press time, solids content, viscosity, raw material variability, emissions, cost, life-cycle performance, and compatibility with particleboard, medium-density fibreboard, plywood, and related engineered wood products. Lignin and tannins are highlighted as the most chemically compatible phenolic platforms, starch and soy systems as abundant but moisture-sensitive binders requiring targeted crosslinking, HMF and furan derivatives as promising aldehyde-type formaldehyde-free crosslinkers, and citric acid systems as attractive polyester-forming binders with pressing-temperature limitations. The review concludes that near-term adoption will most likely proceed through hybrid and partially biobased systems, whereas fully biobased adhesives require faster curing, standardized feedstocks, pilot-scale validation, and transparent techno-economic and life-cycle assessment. Full article

The effects of asparaginase treatment and conditions of its use (enzyme dose and dough resting time) on the formation of heat-induced contaminants, namely, acrylamide (ACR) and 5-hydroxymethylfurfural (HMF), were investigated in wholemeal wheat biscuits. In addition, potential impacts on sensory-related quality attributes were assessed through instrumental analysis of colour, texture, and volatile organic compounds (VOCs). Three levels of asparaginase addition (100, 300, and 500 ASNU kg⁻¹ flour) were tested and compared with an untreated control, with and without the application of a 15 min dough resting step. Results confirmed the effectiveness of asparaginase in reducing ACR levels in the final biscuits, showing a dose-dependent response with reductions of up to 68% at 500 ASNU kg⁻¹ flour. A dough resting step tend to further lower ACR content. In contrast, asparaginase treatment did not exert a consistent effect on HMF formation, whereas dough resting tended to decrease it. Moreover, asparaginase addition at the highest dose reduced the level of several Maillard reaction-derived VOCs by approximately 30%. Overall, asparaginase treatment markedly reduced ACR formation while causing changes in some odour-active compounds in biscuits. Further sensory evaluation will be necessary to determine whether these changes are perceptible and may influence consumer acceptance. Full article

This study investigates subcritical water extraction (SWE) as an alternative to hydroalcoholic extraction for the production of Echinacea purpurea root extracts standardized to hydroxycinnamic acids (cichoric and caftaric acids). Extractions were performed at 100 °C, 125 °C, 150 °C, and 170 °C for 10–30 min. The recovery of cichoric and caftaric acids was significantly (p < 0.05) influenced by extraction temperature, with the highest values obtained within the range of 100–125 °C. Further experiments identified 110 °C for 10 min as the optimal condition, yielding the highest cumulative recovery of cichoric and caftaric acids (1.87 ± 0.10% of dry material). In the resulting dry extracts, SWE at 100–125 °C produced hydroxycinnamic acid contents of 5.5–7.1%, whereas the total dry extract yield in-creased from 24–28% at 100 °C to 40–41% at 150–170 °C (p < 0.05). Higher temperatures, however, reduced cichoric and caftaric acid cumulative content to 0.6–1.7% (p < 0.05), indicating a degradation of the target compounds. In contrast, total polyphenol recovery in-creased continuously with temperature, reaching 4.86% at 170 °C for 30 min. This was accompanied by marked increases in rutin, gallic and caffeic acid, reaching 458.5 mg/100 g dry weight (DW), 175.5 mg/100 g DW and 945.7 mg/100 g DW (p < 0.05), respectively, suggesting the release of bound phenolics following partial disruption of plant cell wall structures. SWE also enhanced the extraction of carbohydrates, uronic acids, fructans, proteins and organic acids, demonstrating an extensive temperature-dependent modification of the root matrix. 5-HMF was not detected in extracts obtained below 125 °C, but increased progressively at higher temperatures, reaching 200 mg/100 g (p < 0.05) at 170 °C. Biological evaluation in the human colorectal adenocarcinoma cell line (HT29) showed favorable cytocompatibility of SWE extracts, confirmed by cell viability, morphological assessment and low DNA damage in the Comet Assay. Overall, SWE enables the production of cichoric and caftaric acid-standardized E. purpurea extracts without organic solvents, supporting its application in pharmaceutical, nutraceutical, food and cosmeceutical products. Full article

The physicochemical composition of honey reflects its botanical origin, environmental conditions, and post-harvest handling; however, studies that combine long-term monitoring data with multivariate and spatial analyses at a metropolitan scale remain limited. This study analyzed acacia, chestnut, flower, and meadow honeys from the Zagreb metropolitan region, Croatia, using a long-term physicochemical quality dataset from the Zzzagimed International Honey Quality Competition collected between 2007 and 2019. From a total database of 351 samples, 82 georeferenced samples from the City of Zagreb and Zagreb County were selected and evaluated for moisture, electrical conductivity, free acidity, and hydroxymethylfurfural (HMF). Most samples met general honey quality requirements: only three samples exceeded the moisture threshold of 20%, and no samples exceeded the limits for HMF or free acidity. Electrical conductivity and free acidity provided the clearest differentiation among honey types, ranging from 0.22 to 1.47 mS/cm and from 9.77 to 27.38 meq/kg, respectively. Multivariate analysis showed that physicochemical variability was structured primarily by honey type, with the first two principal components explaining 62.8% of the total variance. Spatial analyses revealed weak to moderate spatial structure, with residual autocorrelation retained only for free acidity. Honeys from the Zagreb region showed good physicochemical quality, and their variability was driven mainly by declared botanical origin rather than by broad City–County differences. Full article

Background: Honey possesses anti-inflammatory, antimicrobial, and wound-healing properties due to its complex mixture of carbohydrates, phenolics, flavonoids, vitamins, and minerals. However, comprehensive data on monofloral honeys from Saudi Arabia’s Qassim region are lacking. Objective: This study evaluated the nutritional composition, glycemic index, antioxidant and anti-inflammatory activities of five Qassim honeys (Talh, Keina, Samr, Berseem, Ashr) and identified chemical components responsible for their therapeutic potential. Methods: Physicochemical parameters, sugar profiles, minerals, vitamins, total phenolic content (TPC), total flavonoid content (TFC), diastase activity, and HMF were analyzed. Antioxidant activity was assessed by DPPH and ABTS assays, anti-inflammatory activity by BSA denaturation inhibition, and in vitro glycemic index by simulated digestion. Statistical comparisons used one-way ANOVA with Fisher’s LSD (n = 5). Results: All honeys met international quality standards (moisture < 20%, HMF < 40 mg/kg, F + G > 60 g/100 g). Samr honey showed the highest TPC (890 mg GAE/kg) and TFC (226 mg QE/kg). Ashr and Berseem exhibited the highest DPPH scavenging (92% and 91%). Samr was the most potent ABTS scavenger (IC₅₀ 26.7 μg/mL). Ashr displayed the strongest anti-inflammatory activity (86.9%), followed by Berseem (72.0%). All honeys had low glycemic index (51–55). Talh and Samr (Acacia-derived) were richest in K, Mg, P, Fe, and Zn; Keina (Eucalyptus) was highest in Ca; Berseem (clover) had the lowest mineral content. Samr honey contained the highest levels of vitamin C and B vitamins. Conclusions: The five Qassim monofloral honeys possess distinct nutritional and bioactive profiles. Samr honey is exceptionally rich in phenolics, flavonoids, and B vitamins, contributing to high antioxidant capacity. Ashr and Berseem honeys showed remarkable anti-inflammatory activity. All honeys are low-glycemic and meet quality standards. These findings support their use as functional foods and provide a basis for botanical authentication and quality control. Full article

Accurate modeling of topside ionospheric electron density is essential for improving GNSS positioning and understanding upper-atmosphere dynamics. A new four-dimensional (spatial and temporal) topside electron density model is developed using global GNSS radio occultation data within an L2-regularized artificial neural network framework. The model combines both empirical and physical variables, including geomagnetic coordinates, temporal parameters, solar flux ($F_{10.7}$), geomagnetic activity index ($Kp$), and key ionospheric parameters (NmF2 and hmF2). To support the modeling framework, two sub-models are first constructed to estimate NmF2 and hmF2 when direct measurements are unavailable. The full model is trained using COSMIC-1 data and evaluated against independent datasets, including COSMIC-1, GRACE, and incoherent scatter radar (ISR). The results show that the proposed sub-models reduce relative errors by 4.5% for hmF2 and 11.0% for NmF2 compared with IRI-2016. For the full topside $N_e$ modeling, the proposed approach achieves improvements of 35%, 36%, and 53% relative to IRI-2016 when evaluated against COSMIC-1, GRACE, and ISR datasets, respectively. A systematic analysis of input variables further indicates that both physical drivers and ionospheric structural parameters play essential roles in determining model performance. The new model incorporated with NmF2 and hmF2 sub-models still achieves a 16% improvement over IRI-2016 based on ISR data. In addition to statistical improvements, the model reproduces key ionospheric features, including the equatorial ionization anomaly (EIA) and the midlatitude summer nighttime anomaly (MSNA), under different solar activity conditions. These results demonstrate that the proposed model captures not only the statistical variability but also the underlying physical behavior of the topside ionosphere. Full article

The selective photocatalytic oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) into high-value 2,5-diformylfuran (DFF) under green conditions is a promising route toward carbon neutrality. However, achieving high efficiency and selectivity in pure water remains challenging due to limited oxygen solubility and nonselective radical reactions. In this study, a series of amorphous MoS₃-modified Zn₃In₂S₆ nanoflowers (x%MS/ZIS) with varying MoS₃ loadings were successfully synthesized via a one-step hydrothermal method and served as the photocatalysts for the highly selective oxidation of HMF to DFF. The incorporation of MoS₃ significantly enhances visible-light absorption, promotes efficient separation of photogenerated carriers, and accelerates surface reaction kinetics. Under visible light irradiation, the optimized 2.4%MS/ZIS catalyst achieves 64.7% HMF conversion and 89.5% DFF selectivity in pure water within 6 h, ~39-fold enhancement in DFF yield compared to pristine Zn₃In₂S₆. Radical scavenging experiments and electron paramagnetic resonance analyses suggest that superoxide radicals (·O₂⁻) and photogenerated holes are the main reactive oxygen species governing the selective oxidation, while the absence of ·OH radicals suppresses overoxidation. This study demonstrates a viable and green strategy for the valorization of biomass platform molecules through visible-light-driven photocatalysis in pure water. Full article

Radio occultation (RO) has become a key technique for monitoring the ionosphere by deriving electron density (Ne) profiles and total electron content (TEC) from GNSS signals. This study assesses the newly deployed PlanetiQ GNOMES constellation by validating its ionospheric Ne profiles and profile-based TEC against collocated measurements from ionosondes and the COSMIC-2 mission under both quiet and disturbed geomagnetic conditions. Data matching for the statistical validation uses conservative spatial thresholds of less than 1° in latitude and longitude and temporal limits of 30 min for ionosondes and 1 h for COSMIC-2, supported by a dedicated sensitivity analysis, whereas storm-time case studies apply tighter temporal collocation and explicit control of the ray path geometry. Quantitative agreement is evaluated using root mean square error (RMSE), mean and absolute mean differences, correlation coefficients, regression analysis, and normalized percentage differences for key F-layer parameters, including the maximum Ne of the F2 layer (NmF2), the peak height of the F2 layer (hmF2), and the critical frequency of the F2 layer (foF2), along with altitude-dependent Ne profiles. PlanetiQ shows strong consistency with ionosonde profiles, with RMSE ranging from 2.94 × 10⁴ to 2.76 × 10⁵ el/cm³, correlations typically exceeding 0.90, and normalized absolute mean differences often near or below about 10–20%, although lower correlations of about 0.31 and 0.69 are found at Poker Flat and Awase, respectively, reflecting complex local structures and regional variability. Comparisons with COSMIC-2 during quiet conditions yield RMSE values between 7.06 × 10⁴ and 2.16 × 10⁵ el/cm³, correlations from 0.94 to 0.99, and percentage differences that generally remain within a few tens of percent, while storm-time analyses show RMSE between 1.12 × 10⁵ and 3.70 × 10⁵ el/cm³ with correlations from 0.80 to 0.99, confirming robust agreement across a wide range of geophysical conditions. Regression results demonstrate slopes near 1.00 and correlation coefficients above 0.90 for NmF2 and foF2 between PlanetiQ and both ionosondes and COSMIC-2, whereas hmF2 exhibits larger scatter, particularly during geomagnetic disturbances; additional binning by spatial and temporal separation indicates that temporal mismatches generally have a stronger impact on discrepancies than horizontal distance. Overall, the results demonstrate that PlanetiQ ionospheric RO data provide accurate and consistent measurements of key ionospheric parameters, comparable to those from COSMIC-2 and ionosondes, and can reliably complement existing observing systems for monitoring ionospheric variability and space-weather impacts. Full article

Variations in sweetness and bitterness among Madhuca longifolia flowers strongly influence their processing value and market acceptance, yet the chemo-diversity underlying these traits remains poorly characterized. This study aimed to unravel accession- and stage-specific differences by integrating physico-biochemical, elemental, and metabolic profiling across thirteen accessions (BM-1 to BM-13) from BUAT, Banda. Sensory and textural evaluations revealed wide diversity, with BM-5 displaying superior sweetness and aroma, whereas BM-6, BM-7, and BM-10 were differentiated by firmness, elasticity, and gumminess. Biochemical analyses across flower development showed that BM-5 consistently maintained higher sugars and β-carotene, while BM-1 exhibited marked reductions in sugars and total phenolics content; meanwhile, antioxidant activity increased with maturity, with BM-5 remaining the most stable. ICP-MS elemental analysis confirmed BM-5 as mineral-rich compared with lower-performing accessions. GC-MS metabolomic profiling of contrasting accessions (BM-1 and BM-5) across stages identified 303 volatile and semi-volatile metabolites, and multivariate analyses (PCA, VIP, volcano plots, pathway enrichment) revealed distinct stage- and accession-dependent patterns. Mature BM-5 was enriched in fermentation- and aroma-related metabolites such as melibiose, furfural, 5-HMF, and furaneol, whereas BM-1 accumulated defense-linked compounds including catechol, benzyl nitrile, and maltol. Overall, the integrated chemo-diversity landscape identifies BM-5 as a superior accession with high processing potential and value-addition prospects. Full article

Crackers are a popular and convenient snack; however, the baking process can produce neo-formed contaminants (NFCs), such as acrylamide (AA) and 5-hydroxymethylfurfural (HMF), through non-enzymatic browning reactions. Conventional analytical methods for quantifying these NFCs are complex, labor-intensive, and require specialized personnel. The main objective of this study was to develop computer vision (CV) models based on surface digital image analysis for the rapid prediction of AA and HMF in crackers. Therefore, five baking temperatures (160, 170, 180, 190, and 200 °C) and times (15, 20, 25, 30, and 35 min) were tested and analyzed using CV alongside conventional analytical methods. CV estimates and analytical measurements for AA (4.35–829 µg kg⁻¹) and HMF (0.004–105.4 mg kg⁻¹) contents were compared using cross-validation with a “leave-one-treatment-out” approach. The average error for missing measurements was 3.10% for AA and 3.28% for HMF, validating CV as an efficient tool for the rapid estimation of these NFCs in crackers. Among the cracker samples with AA content below the EU benchmark of 400 μg/kg, evaluated using the Check-All-That-Apply (CATA) test, consumers preferred the samples baked at 180 °C for 25 min, which also exhibited the lowest levels of both AA and HMF. Full article

This study investigates the ionospheric response in the Southern and Northern Hemispheres over the period from 25 December 2024 to 7 January 2025. A major geomagnetic storm occurred on 1 January 2025, following the consecutive solar wind eruptions on 29–31 December 2024 and 1 January 2025. Global geomagnetic activity monitoring data showed that the Kp index surged to 8+, indicating the occurrence of this major geomagnetic storm. By analyzing the ionosonde, GNSS-TEC, and satellite in situ detection data from Learmonth, Australia (−21.8° N, 114.1° E), as well as Wake Island (19.29° N, 166.65° E), we found that the ionospheric anomalies in the two regions exhibited different patterns. The ionospheric parameters in Learmonth changed much more severely than those in Wake Island in the Pacific region. Relative to normal conditions, the disturbed ionosphere over Learmonth during 1–3 January 2025 exhibited a strong negative storm phase: f_oF₂ decreased by 31.4%, TEC dropped by 27.17%, and M3000F₂ declined by 41.2%, while h_mF₂ increased by 5.2%. This work provides an analysis of the differences in the ionosphere between the Northern and Southern Hemispheres affected by geomagnetic storms in late 2024. These findings highlight the need to incorporate hemispheric asymmetry into ionospheric dynamics models. Full article

Given the depletion of fossil resources and mounting environmental pressures, the efficient conversion of the biomass-derived platform molecule 5-hydroxymethylfurfural (HMF) into the liquid fuel 2,5-dimethylfuran (DMF) is of critical strategic importance. The recent advances in the hydrogenolysis of HMF to DMF were systematically summarized in this review. The performance advantages and limitations of monometallic catalysts, including noble metals and non-noble metals, were discussed. The bimetallic active centers engineered through synergistic effects to enhance activity were summarized. Crucially, the roles of the physicochemical properties of catalyst supports and the hydrogen donors in governing reaction pathways and efficiency were also analyzed in depth. Finally, future research directions were proposed to address current challenges related to catalyst durability and economic viability. Full article

The selective oxidative transformation of 5-hydroxymethylfurfural (HMF) is a key route toward producing a wide variety of chemicals in the biorefinery industry. Herein, we report a NiAl layered double hydroxide (NiAl-LDH) catalyst as a highly effective electrocatalytic oxidation catalyst for the transformation of HMF into 2,5-diformylfuran (DFF), a valuable furan-based chemical, with about 75.53% DFF selectivity under neutral conditions. It demonstrated good stability without deactivation after 9 cycles of repeated electrolysis. The NiAl-LDH electrocatalyst was deposited on a nickel foam support via a hydrothermal method, and its structural properties and surface morphology were extensively investigated. Systematic studies of reaction temperature, current intensity, and electrolyte concentration revealed that the neutral electrolyte plays a critical role in achieving high DFF selectivity by suppressing aldehyde over-oxidation. Mechanistic investigations with electrochemically active surface area (ECSA), electrochemical impedance spectroscopy (EIS), Tafel slope and density functional theory (DFT) calculations revealed that the reversible transformation between Ni(OH)₂ and active NiOOH species in the NiAl-LDH electrocatalyst was the main reason for the oxidation of HMF, while the incorporation of Al provided structural support to the electrode, enabling the catalyst to exhibit excellent stability during electrolysis. Overall, this work demonstrates an active, earth-abundant metal electrocatalyst for the valorization of biomass-derived 5-HMF to DFF. Full article

This study presents a data-driven framework to predict and optimize the quality of date juice (DJ) produced from two commercially important Saudi cultivars (Sukkary and Khlass) using physicochemical and processing variables as model inputs. A total of 1600 experimental runs were performed by systematically varying initial fruit moisture content, extraction temperature (20, 40, 60, and 80 °C), mixing velocity (10, 20, 30, 40, and 50% of maximum speed), and date-to-water ratios (1:1, 1.5, 2, 2.5, and 3 w/w). The produced juices were characterized at 25 °C for water activity, moisture content, density, pH, total soluble solids (°Brix), turbidity, viscosity, hydroxymethylfurfural (HMF), browning index, extraction time, electrical energy consumption, and an integrated Quality Index (Qi). A feed-forward artificial neural network (ANN; 7–15–1) with a hyperbolic tangent transfer function was developed and validated using normalized datasets, and its performance was benchmarked against multiple linear regression (MLR). The ANN consistently outperformed MLR for Qi prediction, achieving higher coefficients of determination and lower error indices across training, testing, and validation, indicating strong generalization and minimal overfitting. Sensitivity analysis highlighted total soluble solids, moisture content, and HMF as the most influential predictors of Qi. Optimal juice quality (Qi ≥ 0.91) was repeatedly achieved under moderate thermal conditions (≈60 °C), with 40% mixing velocity and a 1:2.5 date-to-water ratio, providing a practical operating window for producing juice at the target °Brix while limiting thermal quality deterioration. Overall, the proposed ANN-based model provides an actionable decision-support tool for process optimization and quality standardization, supporting the transition of date-juice manufacturing toward Industry 4.0 through data-driven monitoring and adaptive control strategies. Full article

This study presents an approach for the “one-pot two-step” synthesis of 2,5-diformylfuran (DFF) from fructose using a metal-free phosphorus-doped carbon nitride (P-CN) catalyst. The bifunctional P-CN integrates P-O bonds for acid-catalyzed fructose dehydration to 5-hydroxymethylfurfural (HMF) and P-C/graphitic-N sites for selective aerobic HMF oxidation to DFF. The 10% P-CN catalyst achieved 91.5% DFF yield during the stepwise oxidation of isolated HMF under the mild conditions (1.5 MPa O₂, 120 °C), while the “one-pot” cascade reaction yielded 63% DFF due to competing side reactions. Characterization revealed that P-doping enhanced porosity (883 m²/g surface area) and electronic properties, with graphitic-N facilitating O₂ activation. P=O groups are hypothesized to mediate proton transfer from reactive substrates via hydrogen-bonding networks, thereby enhancing acid-catalyzed pathways. NH₃-TPD and XPS confirmed tailored acid sites and P-N/C elemental synergism, while FT-IR demonstrated substrate adsorption via P=O/HMF-OH interactions. The catalyst retained stability over multiple cycles, demonstrating its practicality. This work advances biomass valorization by elucidating the dual-role design of nonmetallic catalysts, offering an eco-friendly alternative to conventional metal-based systems. Full article