Search Results (479)

This study comprehensively characterised the volatile composition of hydrolates obtained as by-products of the hydrodistillation of orange, mandarin, and clementine peels. Enzymatic pretreatments using pectinase, cellulase, xylanase, or their mixture were applied in purified water or citrate buffer (pH 5) prior to Clevenger hydrodistillation, and volatile profiles were analysed by HS–SPME GC–MS. Across all citrus species, hydrolates were dominated by oxygenated monoterpenes and alcohols, with α-terpineol and linalool identified as the principal constituents. Statistical analysis suggested differences in hydrolate volatile composition following enzymatic pretreatment in citrate buffer with cellulase, xylanase, or their combination (p < 0.05); notably, α-terpineol content in mandarin hydrolates nearly doubled after these treatments. Enzyme-free reflux extraction in water also led to observable changes in volatile profiles (p < 0.05), highlighting the importance of including both untreated and enzyme-free controls when evaluating enzymatic effects. The study also illustrates the distinct distribution of dominant volatiles between hydrolates with prevailing α-terpineol. These findings demonstrate the potential of enzymatic hydrodistillation for the valorisation of citrus peel by-products by enabling modulation of hydrolate volatile composition and supporting more sustainable use of citrus processing residues. Full article

Thermal modification is widely applied to improve the durability and dimensional stability of wood; however, it alters the emission profile of volatile organic compounds (VOCs), which may affect indoor air quality. This study evaluated the effect of accelerated aging on VOC emissions from thermally modified Norway spruce (Picea abies) wood. Untreated and thermally treated samples (160, 180, and 210 °C) were subjected to accelerated aging in a xenon test chamber for 600 h. VOC emissions were analyzed using headspace gas chromatography–mass spectrometry (HS-GC-MS), and total VOC emissions (TVOC) were calculated from peak areas. Thermal modification significantly reduced TVOC compared to untreated wood, with samples treated at 210 °C showing up to a 376-fold decrease. Increasing modification temperature reduced the amount and variability of emitted VOCs and altered their chemical composition. Terpenes dominated in untreated wood, particularly α-pinene (51%), whereas thermally treated samples showed lower terpene content and higher proportions of carbonyl compounds such as furfural. Accelerated aging further affected VOC emissions, including a 42% decrease in TVOC for the 160 °C sample and compositional shifts characterized by the disappearance or formation of specific compounds. Thermal modification and subsequent aging substantially modify VOC emission profiles and improve emission stability of thermally treated spruce wood. Full article

To address the critical limitation of insufficient high-temperature structural stability in traditional formaldehyde-resorcinol aerogels for thermal protection applications, this study designed and fabricated a high-silica fiber felt-reinforced phenolic aerogel composite capable of in situ ceramization. The thermal insulation performance, structural stability, mechanical properties, and oxidation resistance mechanism after heat treatment at 1000 °C for 600 s were systematically investigated. Results demonstrated tunable density (0.398–0.629 g·cm⁻³), low room-temperature thermal conductivity (0.0414 W·m⁻¹·K⁻¹), and a stabilized back temperature of 408.6 °C during butane torch flame testing. After high-temperature treatment, the composite series exhibited a minimum volume shrinkage of 13.9% and a maximum mass retention of 77.6%. Specifically, the compressive strength and specific strength of the HS/C-75 sample reached 4.39 and 1.96 times those of the HS/C-0 sample, respectively. Further analysis revealed that the synergistic effect between the skeletal support of high-silica fibers and the in situ-formed ceramic phase effectively suppressed thermal shrinkage and improved oxidation resistance, achieving an optimized balance between thermal insulation and mechanical integrity. This work provides a theoretical foundation and viable technical pathway for developing advanced thermal protection materials with enhanced stability and reliability. Full article

Slovenia preserves one autochthonous pig breed, the Krškopolje pig, whose meat has been reported to exhibit a favourable fatty acid profile compared with that of modern breeds. However, meat quality is not solely determined by genetics; the production system also influences it, as organic and conventional farming differ in feed composition, housing and outdoor access. This study aimed to compare the effects of pig breed (Krškopolje vs. modern) and production system (organic vs. conventional) on the fatty acid composition and volatile organic compound (VOC) profile of pork. Fatty acid composition was determined by GC-FID after methylation, and the VOCs profile was obtained using headspace solid-phase microextraction (HS-SPME) coupled with GC-MS. Results showed that Krškopolje meat had higher SFA and MUFA, while modern pig meat had higher PUFAs, particularly n-6, reflecting genetic and dietary influences. Modern breeds also showed greater fatty acid response to the rearing system than the Krškopolje breed. Several VOCs were unique to modern breed pigs, indicating breed-specific differences in lipid composition, amino acid metabolism, and microbial activity. Aldehydes were the dominant VOC class in both breeds, slightly higher in Krškopolje meat. OPLS-DA model revealed breed-related differences in VOCs, pinpointing compounds likely responsible for breed-specific aroma and flavour. Full article

As core materials in pavement structures, asphalt mixtures are characterized by intensive energy consumption and significant carbon footprints throughout their construction cycle, making their construction a typical high-carbon process in road engineering. Warm-mix technology, leveraging its key advantages of reducing mixing temperatures and cutting energy consumption and emissions, has emerged as a green alternative to hot-mix mixtures. However, existing studies have lacked systematic environmental impact assessments of combinations of asphalt from different oil sources and warm-mix technologies. This study focuses on the additive type warm-mix technology (Evotherm M1) and uses three typical oil sources of 70# road petroleum asphalt. Using headspace gas chromatography–mass spectrometry (HS–GC–MS) and Life Cycle Assessment (LCA) methods, a systematic analysis was conducted across three dimensions: multi-component pollutant emissions, full life cycle stages, and multi-type warm-mix technologies. The analysis focused on the influence of warm-mix treatment on Volatile Organic Compound (VOC) emissions, as well as energy consumption and carbon emission characteristics throughout the full life cycle of the construction phase. Results indicate that warm-mix treatment significantly inhibits VOC emissions from all three oil source asphalts. The largest reduction was observed in Asp-A (74.66%), followed by Asp-C (69.27%), and the smallest in Asp-B (46.47%). The VOC compositions shifted from being dominated by oxygenates to a coexistence of multi-components such as alkanes and aromatic hydrocarbons. In the life cycle of the construction phase, compared with hot-mix mixtures, warm-mix technology reduced total energy consumption by 5.50%–5.56% and carbon emissions by 4.47%–4.52%. Raw material production and mixture mixing stages were identified as the core links for energy consumption and carbon emissions, accounting for over 80% of the totals. Differences among oil sources mainly stemmed from refinery power structure and the temperature–viscosity properties of asphalt. The research results provide theoretical support for material selection and process optimization of green construction of asphalt pavement using additive-based warm-mix technology. Full article

Enzymatic pretreatment is a promising method for modulating essential oil isolation. This study evaluated the effects of pectinase, cellulase, xylanase, and their mixture, applied in purified water or citrate buffer before Clevenger hydrodistillation, on the yield and volatile composition of essential oils from orange, mandarin, and clementine peels. Essential oil yield increased slightly for orange and mandarin peels (up to approximately 2%) compared to non-enzymatic controls, while clementine yield was unaffected. Limonene remained the dominant compound in all oils, reaching 81.16% in orange, 77.50% in mandarin, and 75.29% in clementine. Enzyme pretreatment particularly affected the secondary components: mandarin peel showed increased sesquiterpenes (up to 60.52%) and aldehydes (up to 4.86%), while clementine oils exhibited higher oxygenated monoterpenes after buffer-based enzymatic treatments. These results indicate that enzyme-assisted pretreatment can modulate the volatile profile of citrus essential oils, although overall yield gains are modest. The inclusion of no-enzyme and no-pretreatment controls is crucial for the reliable assessment of enzymatic effects under laboratory conditions. This systematic approach provides insight into enzyme-assisted extraction, highlighting its potential to influence essential oil quality and composition rather than dramatically increase yield, and offers a foundation for further optimization research. Full article

Unsymmetrical dimethylhydrazine (UDMH) serves as a high-performance liquid rocket propellant extensively utilized in the global aerospace industry, and its environmental release and leakage (particularly into soil systems) pose severe risks to ecological integrity and human health. As one of the few studies to quantitatively correlate soil physicochemical properties with UDMH degradation kinetics and pathway partitioning using controlled incubation experiments, this work aims to reveal the environmental hazards of UDMH in soil and provide a theoretical basis for subsequent remediation. The temporal degradation dynamics of UDMH in three comparative soil matrices (yellow-brown soil, red soil and black soil) were explored, correlations between soil physicochemical characteristics and UDMH degradation behavior were clarified, and UDMH degradation pathways were quantified. Headspace solid–phase microextraction (HS–SPME) was adopted as the pretreatment method, and gas chromatography–mass spectrometry (GC–MS) was used to identify UDMH and its transformation products (TPs) in soil incubation. From the GC–MS chromatogram, UDMH and its TPs—formaldehyde dimethylhydrazone (FDMH), acetaldehyde dimethylhydrazone (ADMH) and 1,1,4,4-tetramethyltetrazene (TMT)—were identified in the three soil matrices. UDMH underwent rapid degradation within the first 7 days of incubation, with degradation rates reaching 66.03%, 67.51% and 73.13% in yellow-brown soil (YS), red soil (RS) and black soil (BS), respectively. Degradation was most rapid in BS, followed by YS and RS. UDMH degraded completely and was undetectable within 30 days of soil incubation in the present study. Correlation analysis of soil physicochemical properties and UDMH degradation behavior revealed a significant influence of these edaphic properties on UDMH degradation dynamics across the tested soil matrices. The analysis of UDMH degradation pathways, including volatilization, photodegradation, microbiological degradation, and others (oxidation and self-degradation, etc.) demonstrated that other pathways (including catalytic transformation, induced transformation or unidentified biotic–abiotic coupled processes) acted as the dominant pathway governing its degradation (accounting for 68.75%). This study provides important insights and theoretical basis for unraveling the environmental fate of UDMH and remediating UDMH-contaminated soils. Full article

Honey is a complex natural product with nutritional and therapeutic properties that depend on the diversity of its chemical composition, which includes volatile organic compounds (VOCs). VOCs in honey are key indicators of its botanical and geographical origin, as well as its quality and authenticity. This review provides a comprehensive overview of the analytical instruments and methods used for the identification and quantification of VOCs in different types of honey. Techniques such as headspace solid-phase microextraction (HS-SPME) are used for VOC extraction, and gas chromatography coupled with mass spectrometry (GC-MS) and electronic nose (e-nose) systems for honey analyses, as well as their advantages, limitations, and applications and challenges related to VOC analysis, such as for different types of honeys, their aroma profile, compound variability, and data interpretation, are also discussed. By summarizing recent advancements in analytical methodologies, this review provides an overview of the analysis of VOCs for authentication and research purposes in honey production and processing. Full article

This study systematically evaluated six white grape cultivars and their wines from Changli, China, through multi-analytical techniques (HPLC, LC-MS/MS, HS-SPME -GC-MS, etc.) to compare oenological parameters, organic acid profiles, phenolic compositions, and aromatic volatiles. Results indicated that the total sugar contents in Aranèle (202.11 g/L) and Viognier (201.12 g/L) berries were significantly higher than those in other varieties. Compared with other varieties, Roussanne grape juice and wine had a higher content of phenolic components, and the fermented Chardonnay wine exhibited a higher proanthocyanidin content. In the flavor profile of the wines, the contents of ethyl octanoate, isoamyl acetate, and α-ionene in Semillon wine (total volatile components in Semillon: 56,147.3 μg/L) were significantly higher than those in the other wines. Additionally, Aranèle wine had the highest phenethyl alcohol content. The principal component analysis (PCA), performed on combined normalized data of organic acids, phenolic components, and volatile compounds, revealed distinct clustering of the six white wines. The first and second principal components explained 41.63% and 43.37% of the total variance, respectively, demonstrating clear differentiation among the six white wines. Sensory analysis revealed no distinct differences in appearance among the six white wines, whereas significant variations were observed in aroma and taste profiles. Full article

Flowering street trees provide ecological services and health benefits to humans. In this study, three commonly used flowering street trees, Paulownia tomentosa (Thunb.) Steud., Melia azedarach L., and Magnolia grandiflora L., were selected for analysis of floral volatiles during different flowering stages along roadsides in Shanghai, China. Headspace sampling solid-phase microextraction (HS–SPME) coupled with gas chromatography–mass spectrometry (GC–MS) was used to identify volatiles from different floral samples. Simultaneously, selected-ion flow-tube mass spectrometry (SIFT–MS) was employed to detect biogenic volatile organic compounds (BVOCs) in roadside air samples. The results indicated that (1) P. tomentosa volatiles consisted predominantly of alcohols and phenolic ethers, M. azedarach volatiles consisted primarily of alcohols and aldehydes, and M. grandiflora volatiles consisted mainly of terpenes. (2) Air samples from P. tomentosa and M. azedarach were dominated by alcohols, whereas air samples from M. grandiflora were dominated by terpenes and aldehydes. The ozone formation potential (OFP) of some VOCs fluctuated throughout the flowering period. (3) Antibacterial and antioxidant volatiles released from the flowers of all species, such as eugenol, have demonstrated health-promoting effects in essential oils. The results of this study provide a foundation for optimizing the selection and planting of flowering street trees in urban roadside areas that will enhance ecological services and public health benefits. Full article

Apple aroma is an important factor influencing consumers’ preferences. To understand the overall flavor characteristics of apples (Ruixue, Liangzhi, Grystal Fuji, and Guifei), volatile compounds and aroma profiles were investigated by headspace–gas chromatography–ion mobility spectrometry (HS-GC-IMS) combined with stir bar sorptive extraction (SBSE) and gas chromatography–mass spectrometry (GC-MS). The results showed that a total of 56 aroma compounds were identified by SBSE-GC-MS, and 39 aroma-active compounds were screened out using aroma intensity (AI) and odor activity value (OAV). Aroma recombination experiments showed enhanced ‘fruity’ and ‘sweet’ notes, whereas ‘floral’, ‘woody’, and ‘green’ aromas were weaker compared to the Crystal Fuji sample. Additionally, GC-IMS coupled with principal component analysis (PCA) was used to distinguish the apple samples, and partial least squares regression (PLSR) was applied to explore the correlation between sensory attributes and characteristic aroma compounds. The results indicated that Crystal Fuji exhibited the greatest correlation with the “woody” attribute, and Ruixue was highly correlated with “fruity”, “green”, and “sour” attributes, while butanoic acid, β-damascenone, butyl acetate, pentyl acetate, furfuryl alcohol, γ-decalactone, and vanillin had a significant impact on the “flower” and “sweet” attributes of Guifei. This study clarified the characteristic aroma composition of the four apple cultivars, providing data support for apple flavor quality evaluation and cultivar optimization. Full article

Synthetic cathinones, frequently used in chemsex, are difficult to identify in postmortem blood due to their short half-life and in vitro degradation. This unusual case of chemsex involving 3-CMC highlights the importance of freezing a blood aliquot and testing for metabolites. A 62-year-old man was found dead with chemsex paraphernalia beside him. Peripheral blood with sodium fluoride (PB), cardiac blood (CB) and urine were collected at autopsy. A PB sample was frozen at −20 °C for cathinone testing. In PB at +4 °C, alcohols were measured by HS-GC/FID, drugs and narcotics by LC-HRMS, GHB by GC-MS and cannabinoids by LC-MS/MS. Analysis of PB at +4 °C revealed a toxic concentration of GHB (330 µg/mL). Determination of cathinones in frozen PB revealed the presence of 3-CMC (17 ng/mL), dihydro-3-CMC and N-desmethyldihydro-3-CMC, while no cathinones or metabolites were identified in samples stored at +4 °C. Only metabolites were detected in urine. This case confirms the need to systematically screen for cathinones in suspected chemsex cases and, due to their instability, to screen for different metabolites and to freeze a blood sample after autopsy. Full article

Oregano (Origanum vulgare L.), basil (Ocimum basilicum L.), rosemary (Rosmarinus officinalis L.), yarrow (Achillea millefolium L.), and thyme (Thymus vulgaris L.) are aromatic medicinal plants rich in bioactive volatile compounds with antioxidant, antimicrobial, and anti-inflammatory properties. This study presents a simple, solvent-free, and eco-friendly headspace GC-MS method for VOC profiling. Optimized thermal pretreatment (40–90 °C) enhanced compound detection, particularly at 70–90 °C, without loss of reproducibility. The approach lowers analytical costs and waste generation, supporting green analytical practices and the sustainable valorization of medicinal herbs as natural functional ingredients. Full article

Background/Objectives: Volatile organic compounds (VOCs) are emerging as non-invasive biomarkers of metabolic and disease-related processes, yet their reliable detection from complex biological matrices such as urine remains analytically challenging. This study aimed to establish a robust, non-targeted headspace solid-phase microextraction gas chromatography–mass spectrometry (HS–SPME GC–MS) workflow optimized for very small-volume urinary samples. Methods: We systematically evaluated the effects of pH adjustment and NaCl addition on VOC extraction efficiency using a 75 µm CAR/PDMS fiber and a sample volume of only 0.75 mL. Method performance was further assessed using concentration-dependent experiments with representative VOC standards and by application to real human urine samples analyzed in technical triplicates. Results: Acidification to pH 3 markedly improved extraction performance, increasing both total signal intensity and the number of detectable VOCs, whereas alkaline conditions and additional NaCl produced only minor effects. Representative VOC standards showed compound-specific linear dynamic ranges with minimal carry-over within the relevant analytical range. Application to real urine samples confirmed high analytical reproducibility, with triplicates clustering tightly in principal component analysis and most metabolites exhibiting relative standard deviations below 25%. Conclusions: The optimized HS–SPME GC–MS method enables comprehensive, non-targeted urinary VOC profiling from limited sample volumes. This workflow provides a robust analytical foundation for exploratory volatilomics studies under sample-limited conditions and supports subsequent targeted method refinement once specific compounds or chemical classes have been prioritized. Full article

One significant trend in the research of plant treatment methods is that regarding the use of natural-based methods in plant protection. In this study, antimicrobial activity and changes in MdPR10 gene expression were tested for a total of five plant pathogens in a model of apple fruits, where strawberry and ivy EOs were used. The vapor-phase chemical composition of both EOs was profiled using HS-GC-MS. qRT-PCR was applied for a bacterial response analysis, together with disk diffusion assays, and minimum inhibitory concentrations were determined. To elucidate the molecular basis of the antibacterial potential of essential oils (EOs), docking analyses were performed. For Xanthomonas arboricola and Pectobacterium carotovorum, the presence of EOs resulted in the downregulation of MdPR10. Strawberry EO was more effective against weakly virulent strains of bacteria; ivy EO had greater inhibitory effects. HS-GC-MS detected 13 volatiles in strawberry EO—dominated by ethyl butyrate, ethyl 2-methylbutanoate, ethyl hexanoate, and ethyl 3-methylbutanoate—and 16 in ivy EO, characterized by monoterpenes and monoterpenoids with 1,8-cineole as the principal component. P-cymene showed the most potent binding activity against D-alanine–D-alanine ligase. Ivy EO has the potential to be effective as a natural preservative alternative mainly in postharvest technology. Full article