Search Results (1,189)

2,5-bis(hydroxymethy)lfuran (BHMF), a renewable compound with extensive industrial applications, can be obtained by selective hydrogenation of the C=O group of 5-hydroxymethylfurfural (HMF), a platform molecule derived from lignocellulosic biomass. In this work, we perform kinetic modeling of the selective liquid-phase hydrogenation of HMF to BHMF over a Cu/SiO₂ catalyst prepared by precipitation–deposition (PD) at a constant pH. Physicochemical characterization, using different techniques, confirms that the Cu/SiO₂–PD catalyst is formed by copper metallic nanoparticles of 3–5 nm in size highly dispersed on the SiO₂ surface. Before the kinetic study, the Cu/SiO₂-PD catalyst was evaluated in three solvents: tetrahydrofuran (THF), 2-propanol (2-POH), and water. The pattern of catalytic activity and BHMF yield for the different solvents was THF > 2-POH > H₂O. In addition, selectivity to BHF was the highest in THF. Thus, THF was chosen for further kinetic study. Several experiments were carried out by varying the initial HMF concentration (C⁰_HMF) between 0.02 and 0.26 M and the hydrogen pressure (P_H2) between 200 and 1500 kPa. In all experiments, BHMF selectivity was 97–99%. By pseudo-homogeneous modeling, an apparent reaction order with respect to HFM close to 1 was estimated for a C⁰_HMF between 0.02 M and 0.065 M, while when higher than 0.065 M, the apparent reaction order changed to 0. The apparent reaction order with respect to H₂ was nearly 0 when C⁰_HMF = 0.13 M, while for C⁰_HMF = 0.04 M, it was close to 1. The reaction orders estimated suggest that HMF is strongly absorbed on the catalyst surface, and thus total active site coverage is reached when the C⁰_HMF is higher than 0.065 M. Several Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic models were proposed, tested against experimental data, and statistically compared. The best fitting of the experimental data was obtained with an LHHW model that considered non-competitive H₂ and HMF chemisorption and strong chemisorption of reactant and product molecules on copper metallic active sites. This model predicts both the catalytic performance of Cu/SiO₂-PD and its deactivation during liquid-phase HMF hydrogenation. Full article

Cooked-rice aroma strongly affects consumer choice, yet the chemical traits distinguishing glutinous rice from normal-amylose japonica rice remain underexplored because earlier studies targeted only a few dozen volatiles using one-dimensional gas chromatography–mass spectrometry (GC-MS). In this study, four glutinous and seven normal Japanese cultivars were cooked under identical conditions, their headspace volatiles trapped with MonoTrap and qualitatively profiled by comprehensive GC × GC-TOFMS. The two-dimensional platform resolved 1924 peaks—about ten-fold previous coverage—and, together with hierarchical clustering, PCA, heatmap visualization and volcano plots, cleanly separated the starch classes (78.3% cumulative PCA variance; Euclidean distance >140). Volcano plots highlighted 277 compounds enriched in the glutinous cultivars and 295 in Koshihikari, including 270 compounds that were not previously documented in rice. Normal cultivars were dominated by ethers, aldehydes, amines and other nitrogenous volatiles associated with grainy, grassy and toasty notes. Glutinous cultivars showed abundant ketones, furans, carboxylic acids, thiols, steroids, nitro compounds, pyrroles and diverse hydrocarbons and aromatics, yielding sweeter, fruitier and floral accents. These results expand the volatile library for japonica rice, provide molecular markers for flavor-oriented breeding and demonstrate the power of GC × GC-TOFMS coupled with chemometrics for grain aroma research. Full article

Candidiasis arises from the proliferation of Candida species in the human body, especially in individuals with compromised immune systems. Efficient therapeutic management of candidiasis is often hampered by the limited availability of potent antifungal drugs and the emergence of drug-resistant strains. We have previously identified the N-[(4-sulfamoylphenyl)methyl][1,1′-biphenyl]-4-carboxamide to have fungistatic and fungicidal properties, likely due to the hydrophobic biphenyl–chemical features affecting the structural organization of Candida spp. cell membrane. Here, we designed and synthesized a novel series of twelve 5-arylfuran-2-carboxamide derivatives bearing a new hydrophobic tail as bioisosteric replacement of the diphenyl fragment. Its antifungal effectiveness against C. albicans, C. glabrata, and C. parapsilosis, including ATCC and clinically isolated strains, was assessed for all compounds. The most active compound was N-benzyl-5-(3,4-dichlorophenyl)furan-2-carboxamide (6), with fungistatic and fungicidal effects against C. glabrata and C. parapsilosis strains (MIC = 0.062–0.125 and 0.125–0.250 mg/mL, respectively). No synergistic effects were observed when combined with fluconazole. Interestingly, fluorescent microscopy analysis after staining with SYTO 9 and propidium iodide revealed that compound 6 affected the cell membrane integrity in C. albicans strain 16. Finally, carboxamide 6 exhibited a dose-dependent cytotoxicity on erythrocytes, based on assessing the LDH release. Full article

A chemical investigation of the EtOAc fraction from soft coral Clavularia viridis resulted in the isolation of 12 undescribed dolabellane-type diterpenoids, namely clavirolides W–Z (1–4), clavularols A–H (5–12), and three known analogs (13–15). Their structures were characterized by an extensive analysis of spectroscopic data, including X-ray diffraction and ECD calculations for the assignment of absolute configurations. The structures of 2 and 4–6 are feathered as peroxyl-substituted derivatives, while compounds 7–12 possess additional oxidative cyclization, including epoxide or furan that are rare in the dolabellane family. All these compounds were evaluated for activities on cytotoxic and anti-inflammatory models. Compound 10 exhibited most potential against NO production in the BV2 cell induced by LPS with an IC₅₀ value of 18.3 μM. Full article

(1) Background: This study investigated changes in bioactive components and volatile compounds (VCs) during the production of red millet by comparing two varieties: Miao Xiang glutinous millet (waxy) and Jigu-42 (non-waxy). The samples were solid-state-fermented with “Red Ferment” and evaluated for bioactive components. (2) Methods: Multiple analytical methods—including principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal PLS-DA (OPLS-DA), cluster analysis, and correlation analysis—were employed to systematically compare bioactive components and VCs. (3) Results: Significant varietal differences were observed: (1) Miao Xiang glutinous millet showed higher monacolin K (MK) and fatty acid contents; (2) Jigu-42 contained significantly more polyphenols; (3) linoleic acid dominated the fatty acid profiles of two varieties; and (4) a total of twenty-seven VCs were identified, including six alcohols, four aldehydes, seven ketones (corrected from duplicated count), two aromatic hydrocarbons, three heterocycles, one acid, three furans, and one ether. (4) Conclusions: The two varieties exhibited significant differences in MK, pigment profiles, fatty acid composition, polyphenol content, and volatile-compound profiles. These findings provide scientific guidance for the selection of the appropriate millet varieties in functional food production. Full article

A novel prefabricated pile foundation is presented to improve the disaster resistance of the pole line. Bearing performance analysis of prefabricated inclined pile foundations for electric poles under downward pressure-horizontal loading is carried out, and the effects of prefabricated foundation dimensions and pile inclination on the horizontal load–displacement curves at the top of the poles, the horizontal displacement and settlement at the top of the piles, the horizontal displacement and tilt rate of the poles’ bodies and piles bending moments are investigated. The findings indicate the following: as the prefabricated foundation size grows, the bearing capacity of the foundation improves, and the anti-overturning ability of the electric pole improves; the foundation size increases from 0.9 m to 1.35 m, the anti-overturning bearing capacity of the foundation increases by 15.77%, the maximum bending moment of the foundation pile body increases by 19.7%, and the maximum bending moment occurs at about 0.2 m of the pile body; the bearing capacity of inclined piles is larger than that of straight piles—with an increase in the pile inclination angle, the foundation bearing performance increases, and the overturning bearing capacity of the poles increases; the pile inclination angle grows from 0° to 20°, the overturning bearing performance of the foundation increases by 19.2%, the maximum bending moment of the foundation piles reduces by 21.2%, and the maximum of the bending moment occurs at the pile body at a position of about 0.2 m. Full article

Resistance of various bacterial pathogens to the activity of clinically approved drugs currently leads to serious infections, rapid spread of difficult-to-treat diseases, and even death. Taking the threats for human health in mind, researchers are focused on the isolation and characterization of novel natural products, including plant secondary metabolites. These molecules serve as inspiration and a suitable structural platform in the design and development of novel semi-synthetic and synthetic derivatives. All considered compounds have to be adequately evaluated in silico, in vitro, and in vivo using relevant approaches. The current review paper briefly focuses on the chemical and metabolic properties of resveratrol (1), as well as its oligomeric structures, viniferins, and viniferin-based molecules. The core scaffolds of these compounds contain so-called privileged structures, which are also present in many clinically approved drugs, indicating that those natural, properly substituted semi-synthetic, and synthetic molecules can provide a notably broad spectrum of beneficial pharmacological activities, including very impressive antimicrobial efficiency. Except for spectral verification of their structures, these compounds suffer from the determination or prediction of other structural and physicochemical characteristics. Therefore, the structure–activity relationships for specific dihydrodimeric and dimeric viniferins, their bioisosteres, and derivatives with notable efficacy in vitro, especially against chosen Gram-positive bacterial strains, are summarized. In addition, a set of descriptors related to their structural, physicochemical, pharmacokinetic, and toxicological properties is generated using various computational tools. The obtained values are compared to those of clinically approved drugs. The particular relationships between these in silico parameters are also explored. Full article

In this work, we described the synthesis of 4-(methoxycarbonyl)phenyl 5-bromofuran-2-carboxylate by reacting 5-bromofuroic acid with methylparaben in the incorporation of DCC/DMAP (Steglich esterification) as coupling agents. Later on, we subsequently synthesized a series of 4-(methoxycarbonyl)phenyl 5-aryl furan-2-carboxylates (5a–5e) through Suzuki coupling catalyzed by palladium (0) between 4-(methoxycarbonyl)phenyl 5-bromofuran-2-carboxylate (3) with several substituted arylated and heteroaryl boronic acids (4). DFT calculations were computed to elucidate electronic structural features of synthesized molecules (5a–5e) and to validate these findings by correlating with theoretical and experimental spectroscopic analysis. Furthermore, geometrical optimization, thermodynamic features, as FMO orbitals, MESP maps, NLO behavior and reactivity descriptors, were also determined from the PBE0 D3BJ/def2-TZVP/SMD_1,4-dioxane theory level to confirm the structural features of synthesized molecules. Full article

Tomatoes are globally esteemed not only for their nutritional value but also for their complex and appealing aroma, a key determinant of consumer preference. The present study aimed to comprehensively characterise the volatilomic fingerprints of three tomato species—Solanum lycopersicum L., S. lycopersicum var. cerasiforme, and S. betaceum—encompassing six distinct varieties, through the application of headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS). A total of 55 volatile organic compounds (VOCs) spanning multiple chemical classes were identified, of which only 28 were ubiquitously present across all varieties examined. Carbonyl compounds constituted the predominant chemical family, with hexanal and (E)-2-hexenal emerging as putative key contributors to the characteristic green and fresh olfactory notes. Notably, esters were found to dominate the unique volatile fingerprint of cherry tomatoes, particularly methyl 2-hydroxybenzoate, while Kumato and Roma varieties exhibited elevated levels of furanic compounds. Multivariate statistical analyses, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), demonstrated clear varietal discrimination and identified potential aroma-associated biomarkers such as phenylethyl alcohol, 3-methyl-1-butanol, hexanal, (E)-2-octenal, (E)-2-nonenal, and heptanal. Collectively, these findings underscore the utility of volatilomic fingerprint as a robust tool for varietal identification and quality control within the food industry. Full article

Dates (Phoenix dactylifera L.) are nutrient-rich fruits with health-promoting properties and broad applications in the food and beverage industries. This study analyzes the chemical properties and volatile profile of fermented date products—juice, alcoholic derivative, and vinegar—to develop a high-quality vinegar with distinct sensory traits. Using HS-SPME-GC-MS, about 50 volatile compounds were identified across six major chemical classes. Juice processing significantly increased volatile release, especially fusel alcohols and furanic aldehydes, due to thermal and mechanical disruption. Fermentation further modified the volatilome, with increased esters and acids in alcoholic and vinegar products. Vinegar was characterized by high levels of acetic acid, fatty acids, phenols, and acetoin (855 mg/L), indicating active microbial metabolism. Ethanol and acidity levels met international standards. Total phenolic content rose from juice (138 mg/L) to vinegar (181 mg/L), reflecting microbial enzymatic activity and acid-driven extraction. These results highlight the metabolic complexity, sensory richness, and functional potential of date-derived fermented products while promoting sustainable use of underutilized fruit resources. Full article

Hotpot dishes are widely favored by consumers for their flavor profiles developed during the cooking process. This study investigated the quality characteristics and volatile compounds (VOCs) of donkey meat slices across varying boiling durations (0–42 s) using gas chromatography–ion mobility spectrometry (GC-IMS). The results demonstrated that donkey meat boiled for 12–18 s exhibited optimal characteristics in terms of meat retention, color parameters, shear force values, and pH measurements. Forty-eight distinct VOCs were identified in the samples, with aldehydes, alcohols, ketones, acids, furans, and esters representing the predominant categories. Among these compounds, 18 were identified as characteristic aroma compounds, including 3-hexanone, 2, 3-butanedione, and oct-1-en-3-ol. Samples subjected to different boiling durations were successfully differentiated through topographic plots, fingerprint mapping, and multivariate analysis. The abundance and diversity of VOCs reached peak values in samples boiled for 12–18 s. Furthermore, 28 VOCs were identified as potential markers for distinguishing between different boiling durations, including 2-butoxyethanol D, benzaldehyde D, and (E)-2-pentenal D. This study concludes that a boiling duration of 12–18 s for donkey meat during hotpot preparation yields optimal quality characteristics and volatile flavor compound profiles and provides valuable insights for standardizing cooking parameters in hotpot preparations of other meat products. It is necessary to confirm this finding with sensory evaluations in further research. Full article

In this study, four lactic acid bacteria (LAB) strains, including Lactiplantibacillus plantarum CICC21790, Lacticaseibacillus casei CICC6117, Lacticaseibacillus rhamnosus ATCC7469, and Limosilactobacillus fermentum CICC22704, were used to ferment a plant-based milk composed of chestnut and soybean. The fermentative characteristics of the four LAB strains and the aroma characteristics of the resulting plant-based milks were systematically investigated. The results showed that all four LAB strains successfully fermented the plant-based milk. The viable cell counts ranged from 7.67 to 8.57 lg CFU mL⁻¹, and pH values were between 3.80 and 4.10. Comprehensive analyses performed using E-nose and HS-GC-IMS revealed distinct aroma characteristics in plant-based milks fermented by different LAB strains. Specifically, LAB fermentation, particularly by the CICC22704, significantly reduced the concentrations of aldehydes (e.g., hexanal, heptanal), thereby diminishing Green aroma characteristics. The increased concentrations of alcohols (e.g., 1-pentanol), ketones (e.g., 2, 3-butanedione) and furan compounds (e.g., 2-pentylfuran) in fermented plant-based milks enhanced Pungent, Creamy, and Fruity aroma characteristics, respectively. Fermentation by CICC21790, ATCC7469, and CICC6117 may result in stronger intensities of these three aroma characteristics compared to fermentation by the CICC22704. For the Fatty aroma characteristic, it was enhanced by CICC21790 fermentation but diminished by ATCC7469, CICC6117, and CICC22704 fermentations. Full article

In this study, we tested a flexible polyurethane (PU) foam, synthesized from bio-based components, for the removal of petroleum-derived fuels from water samples. The PU was synthesized via the prepolymer method through the reaction of PEG 400 with L-lysine ethyl ester diisocyanate (L-LDI), followed by chain extension with 2,5-bis(hydroxymethyl)furan (BHMF), a renewable platform molecule derived from carbohydrates. Freshwater and seawater samples were artificially contaminated with commercial diesel, gasoline, and kerosene. Batch adsorption experiments revealed that the total sorption capacity (S, g/g) of the PU was slightly higher for diesel in both water types, with values of 67 g/g in freshwater and 70 g/g in seawater. Sorption kinetic analysis indicated that the process follows a pseudo-second-order kinetic model, suggesting strong chemical interactions. Equilibrium data were fitted using Langmuir and Freundlich isotherm models, with the best fit achieved by the Langmuir model, supporting a monolayer adsorption mechanism on homogeneous surfaces. The PU foam can be regenerated up to 50 times by centrifugation, maintaining excellent performance. This study demonstrates a promising application of this sustainable and bio-based polyurethane foam for environmental remediation. Full article

The repair efficiency of various self-healing materials often depends on the ability of the prepolymer and curing agent to form mixtures. This paper presents a synthesis and study of the properties of modified self-healing polyurethanes using the Diels–Alder reaction (DA reaction), obtained from a maleimide-terminated preform and a series of furan–urethane curing agents. The most commonly used isocyanates (4,4′-methylene diphenyl diisocyanate (MDI), 2,4-tolylene diisocyanate (TDI), and hexamethylene diisocyanate (HDI)) and furan derivatives (furfurylamine, difurfurylamine, and furfuryl alcohol) were used as initial reagents for the synthesis of curing agents. For comparative analysis, polyurethanes were also obtained using the well-known “traditional” approach—from furan-terminated prepolymers based on mono- and difurfurylamine, as well as furfuryl alcohol and the often-used bismaleimide curing agent 1,10-(methylenedi-1,4-phenylene)bismaleimide (BMI). The structure and composition of all polymers were studied using spectroscopic methods. Molecular mass was determined using gel permeation chromatography (GPC). Thermal properties were studied using TGA, DSC, and TMA methods. The mechanical and self-healing properties of the materials were investigated via a uniaxial tensile test. Visual assessment of the completeness of damage restoration after the self-healing cycle was carried out using a scanning electron microscope. It was shown that the proposed modified approach helps obtain more durable polyurethanes with a high degree of self-healing of mechanical properties after damage. Full article

Aroma is an important indicator for evaluating the quality of baijiu. In this study, we determined the aroma-active compounds in four representative brands of strong-aroma baijiu from Sichuan and Jianghuai regions through GC-MS/O, and GC-TOF-MS quantification. In addition, the non-volatile composition of four baijiu samples was quantified by BSTFA derivatization and GC-MS. By constructing a full recombination model containing both volatile and non-volatile components, the effect of different groups of non-volatile compounds on the aroma of strong-aroma baijiu was evaluated through recombination-omission tests. A total of 72 aroma-active compounds and 59 non-volatile compounds were identified and quantified. The results indicated that pyrazines, furfural, and furan derivatives displayed higher aroma intensities in strong-aroma baijiu produced in Sichuan compared to that produced in Jianghuai. The recombination model that included both aroma-active and non-volatile compounds showed a closer resemblance to the original baijiu samples, underscoring the critical role these compounds play in shaping the dominant aroma profile of strong-aroma baijiu. Non-volatile compounds significantly influenced six aroma attributes: fruity, sweet, sauce, pit, acidic, and alcoholic notes. Omission tests revealed that among posorly volatile organic acids, monobasic acids had distinct effects on the aroma profile, while dibasic acids did not show any noticeable influence on the sensory characteristics. Full article