Search Results (284)

Hydrophobic eutectic solvent systems (ESSs) were prepared and characterized using temperature-dependent thermophysical and transport property measurements, supported by thermal analysis. The investigated systems comprise terpene-based mixtures, menthol:octanoic acid (1:2) and menthol:decanoic acid (1:1), and thymol-based mixtures, thymol:butanol (1:1), thymol:hexanol (1:1), thymol:octanoic acid (1:1), and thymol:oleic acid (1:1), as well as salt-containing ESSs based on tetrabutylphosphonium bromide (TBPBr), TBPBr:octanoic acid (1:1), and TBPBr:lauric acid (1:1). Density, dynamic viscosity, and electrical conductivity were measured at atmospheric pressure (p = 0.1 MPa) over 293.15–313.15 K. From density data, molar volumes and isobaric thermal expansion coefficients were calculated. The temperature dependence of viscosity was correlated with both Arrhenius and Vogel–Fulcher–Tammann equations. Conductivity results were used to compute molar conductivities, and the coupled conductivity–viscosity behavior was assessed via Walden analysis to quantify deviations from ideal electrolyte behavior and estimate ionicity. Thermal behavior and stability were evaluated by differential scanning calorimetry (DSC) and simultaneous thermogravimetric analysis (TG/DSC). The resulting dataset enables a consistent comparison of volumetric, flow, and ion transport descriptors across fully molecular terpene-based mixtures and TBPBr-containing systems. Overall, the combined transport descriptors, including Walden analysis, provide a practical framework for distinguishing molecular from salt-containing hydrophobic ESS families and support formulation selection for temperature-dependent applications, particularly in biphasic extraction processes. Full article

The development of sustainable and environmentally benign N-methylation methodologies is essential for enhancing sustainable synthetic practice in pharmaceutical manufacturing. In this study, we demonstrate that microwave heating (MWH) markedly enhanced the efficiency of cobalt-catalyzed N-methylation using methanol or methanol-d₄ as green C1 sources. Compared with conventional heating (CH), MWH enabled highly efficient syntheses of key pharmaceutical intermediates—including 6-dimethylamino-1-hexanol, imipramine hydrochloride, and butenafine hydrochloride—under milder conditions and shorter reaction times and without generating hazardous halogen-containing waste. UV–vis spectroscopic analysis revealed that MWH accelerated the transformation of Co(acac)₂ into catalytically active Co species by approximately four-fold, providing a mechanistic basis for the enhanced reactivity. We hypothesized that this effect was caused by the selective microwave heating of the catalyst, which in turn promoted the rapid generation of catalytically active species. Notably, MWH also significantly improved the N-trideuteromethylation of amines using methanol-d₄, achieving a 95% yield for imipramine-d₃ hydrochloride versus 32% under CH. Molecular dynamics simulations indicated that methanol-d₄ exhibited slower dipole relaxation and enhanced cluster fragmentation under microwave fields, improving catalyst–substrate contact, while kinetic isotope effects stabilized reactive intermediates. These synergistic effects account for the pronounced microwave promotion observed in deuterated systems. Overall, the combination of MWH and cobalt catalysis offers an energy-efficient, waste-minimizing, and environmentally benign strategy for the scalable synthesis of both methylated and deuterated amines. Full article

To explore the characteristic volatile compounds of ‘Hujing Milu’ peaches from different growing regions, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) and headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) were employed to analyze volatile components in samples from six production areas. A total of 73 and 56 volatile compounds were identified by HS-SPME-GC-MS and HS-GC-IMS, respectively. Quantitative analysis revealed that esters, aldehydes, and alcohols were the main contributors to the aroma profile, accounting for over 70% of the total relative content. Combined with chemometric analysis (VIP > 1 and OAV/ROAV > 1), 17 potential biomarkers were identified that can distinguish ‘Hujing Milu’ peaches from different regions, including ethyl acetate, hexanol, (E)-2-nonenal, and dihydro-β-ionone. Moreover, soil properties of these regions and their correlation with volatile compounds were analyzed to elucidate the formation mechanisms of characteristic aromas. The results showed that ethyl acetate exhibited a significant positive correlation with soil pH (r = 0.530, p < 0.05), whereas dihydro-β-ionone showed a significant positive correlation with soil organic matter (r = 0.587, p < 0.05) and available potassium (r = 0.830, p < 0.05). This study identified characteristic volatile compounds of ‘Hujing Milu’ peaches from different regions, providing a reliable technical basis for origin traceability and the enhancement of aroma quality in ‘Hujing Milu’ peaches. Full article

Although Telenomus remus is an important parasitoid of Spodoptera frugiperda, the chemical basis for its host selection behavior remains unclear. To elucidate the chemical basis of this behavior, this study combined behavioral ecology and chemical ecology methods to systematically investigate the host location and recognition behaviors of this wasp, as well as the semiochemicals that regulate these behaviors. In Y-tube olfactometer assays, T. remus exhibited a significantly stronger olfactory preference for eggs of S. frugiperda over those of S. litura (p < 0.05) or the non-host Ostrinia furnacalis. A total of 759 metabolites belonging to 11 categories were identified via metabolomics analysis, and principal component analysis (PCA) clearly distinguished between host eggs and non-host eggs. Analysis of differential metabolites revealed that the significantly upregulated metabolites in host eggs mainly included aldehydes, ketones and esters, followed by hydrocarbons, alcohols and amines. Subsequently, we screened and verified the effects of the significantly upregulated metabolites in host eggs compared with non-host eggs on the host-selection behavior of T. remus, including indole, 2-hexanol, and trans-1,2-dimethylcyclohexane, as well as 2-heptadecanone and n-nonadecane—two alkane compounds which are specifically upregulated on the surface of S. frugiperda eggs. Behavioral validation demonstrated that 2-hexanol exerted a significant repellent effect on T. remus, whereas trans-1,2-dimethylcyclohexane exhibited a significant attractive effect on the parasitoid wasp. Among the metabolites specifically upregulated in S. frugiperda eggs, 2-heptadecanone exhibited significant attractive activity at concentrations ranging from 0.1 to 1.0 mg/mL. This study is the first to report that the cycloalkane compound trans-1,2-dimethylcyclohexane acts as a potential broad-spectrum chemical marker for T. remus to recognize the eggs of host species belonging to the family Noctuidae, while 2-heptadecanone may further enhance its preference for the optimal host S. frugiperda. These findings provide novel candidate molecular targets for the development of behavioral regulators targeting egg parasitoids against S. frugiperda. Full article

Climate change-driven abiotic stresses threaten global potato production, yet stress-specific adaptive mechanisms remain poorly defined. We demonstrate that heat, drought and salt stresses induce fundamentally distinct physiological and biochemical responses in potato plants. Photosynthetic performance and gas exchange showed stress-specific patterns, with heat stress (HS) maintaining elevated carbon metabolism, drought stress (DS) causing severe photosynthetic suppression and water deficit, while salt stress (SS) exhibited intermediate physiological impairment. Secondary metabolite (SM) profiling revealed a corresponding stress-specific signature, where sesquiterpenes (caryophyllene, copaene, humulene) were dramatically elevated under HS but suppressed under DS (which specifically enhanced 1-hexanol and trans-sesquisabinene hydrate), while SS induced copaene and cis-β-farnesene but reduced caryophyllene. Phytohormone analysis demonstrated differential accumulation patterns across stresses: JA, JA-Ile, SA and ABA were maximally elevated under HS, moderately increased under DS, while SS uniquely maintained basal JA/JA-Ile with enhanced SA and ABA. Pharmacological intervention using hormone biosynthesis inhibitors (DIECA, SHAM, Jarin-1, AIP, ABT, fluridone) and exogenous ABA confirmed stress-specific regulatory networks. These findings establish a stress-specific hormone–metabolite regulatory framework, providing a molecular basis for developing climate-resilient potato genotypes. Full article

This study investigates the influence of grape pomace pressing on the chemical composition and sensory characteristics of Trepat grape pomace distillates from two consecutive vintages (2012 and 2013). Distillates obtained from pressed pomace showed higher ethanol strengths than those from unpressed pomace (64% v/v versus 54% v/v) and higher concentrations of several volatile compounds, including methanol, hexanols, aldehydes, and acetate esters. In contrast, distillates from unpressed pomace retained higher levels of terpenes and farnesols. Principal component analysis (PCA) highlighted differences among samples according to both vintage and pomace treatment, reflecting technological and vintage-dependent variability. Pressed pomace distillates contained higher concentrations of fruity and floral acetate esters (2-phenylethyl acetate and 3-methylbutyl acetate) than unpressed pomace distillates; however, sensory evaluation by an expert panel indicated that their fruity expression was often masked by undesirable notes such as rancid and solvent-like aromas. Unpressed distillates tended to be described as more harmonious and mellow and were perceived as having higher overall quality. Although several compounds exceeded their odor activity values (OAV > 1), their potential positive sensory contribution was frequently counterbalanced by elevated concentrations of aldehydes and higher alcohols. Overall, the results indicate that pomace pressing influences the volatile composition of Trepat pomace distillates and may affect sensory balance, suggesting that careful control of pressing conditions could contribute to improving the aromatic quality of grape pomace spirits. Full article

The growing interest in functional beer production has led to the exploration of unconventional raw materials, such as hemp (Cannabis sativa L.), for brewing applications. This study aimed to evaluate the volatile organic compound (VOC) profile and the macro- and microelement composition of barley wort enriched with varying proportions (10% and 30%) of malted and unmalted hemp seeds, using solid-phase microextraction followed by gas chromatography–mass spectrometry (SPME–GC–MS) and atomic absorption spectrometry (AAS). A total of 64 VOCs were identified across four wort variants: control (barley malt only), 10% malted hemp, 30% malted hemp, and 30% unmalted hemp. The aroma profile was significantly influenced by compounds such as 2,3-butanediol, 1-hexanol, 3-methyl-1-butanol, 3-hydroxy-2-butanone, hexanoic acid, and 4-vinylguaiacol (p < 0.001). Principal component analysis (PCA) revealed clear separation between wort types based on the relative abundance of alcohols, acids, ketones, and phenols, indicating a progressive shift from sweet/malty toward acidic, green, and herbal aroma notes as hemp addition increased. Notably, unmalted hemp seeds resulted in a pronounced dominance of hexanoic acid, which may contribute to earthy and rancid sensory attributes. The evaluation of selected mineral elements showed that the key macroelements differentiating the worts were potassium, magnesium, phosphorus, and calcium, while among the microelements the distinguishing elements were manganese, iron, and sodium. These findings demonstrate the strong modulating effect of aromatic hemp-derived materials on the aroma composition and selected mineral content of brewing worts, supporting their targeted use in novel beer formulations. Full article

Understanding the chemical basis for the quality differentiation of wines is essential for breeding and quality control. This study performed a comparative analysis of volatile aroma compounds (VACs), organic acids, and color characteristics in berries and wines from Vitis amurensis (V. amurensis), its interspecific hybrids, and Vitis labrusca (V. labrusca). Hexanal was identified as the primary contributor to grape aroma in V. amurensis berries. 1-Hexanol and isoamyl acetate were the key aroma marker distinguishing wines produced from V. amurensis from its interspecific hybrids. V. amurensis exhibited enhanced metabolism of C6 alcohols, aldehydes, and esters during fermentation. Its wines showed the highest pigment retention and significantly greater anthocyanin content, resulting in the most intense and stable red-purple color compared to other genotypes. Correlation analyses indicate high anthocyanin retention and high color intensity in wines produced from V. amurensis were associated with its high organic acid levels, particularly influenced by tartaric acid, lactic acid, and citric acid. This work clarifies the chemical evolution underlying V. amurensis wine’s sensory superiority and supports breeding, quality control, and product development. Full article

Objectives: The aroma profile is a key determinant of fruit quality. Methods: In this study, mature ‘Summer Black’ grape berries were collected from 36 major producing areas in southern China to evaluate regional differences in fruit quality, volatile compounds were analyzed by via GC-MS, and a representative volatile profile was established. Furthermore, transcriptome sequencing was employed to identify key genes involved in the phenylpropanoid biosynthesis pathway related to aroma formation. Results: The results showed the following: (1) Samples from CD-2 exhibited the highest soluble solid content and the largest TSS/TA ratio. (2) A total of 20 volatile compounds were selected as indicators for the aroma fingerprint. MS-1 samples contained the most diverse aroma compounds (19 types), while CS-2 had the fewest (12 types). (3) Eight aroma compounds were consistently detected across all regions: hexanal, trans-2-hexenal, n-hexanol, β-citronellol, geraniol, nerol, benzyl alcohol, and phenethyl alcohol. Among these, hexanal and trans-2-hexenal were the most abundant; phenylethyl alcohol exhibited the most significant variation in percentage content across all samples, and was determined to be the representative and dominant volatile compound in ‘Summer Black’ grapes. (4) A transcriptome analysis of six representative regions identified 15 differentially expressed genes associated with phenylpropanoid biosynthesis and metabolism. Among them, PAO (Vitvi04g01467) was significantly correlated with phenethyl alcohol content. Conclusions: These findings provide a basis for evaluating the aroma quality of ‘Summer Black’ grapes and offer insights for regional cultivation selection. Full article

The application of zinc oxide nanoparticles (ZnONPs) in agriculture is expanding due to their biostimulant potential; however, their influence on plant chemical communication and associated microbial communities remains not fully characterized. This study presents a multi-perspective analysis contrasting the effects of ZnONPs with those of conventional microparticulate ZnO (Bulk) on Capsicum annuum seedlings grown in substrate at 50 and 500 mg kg⁻¹. Results indicate that, at high doses, the bulk material (B500) led to higher foliar zinc accumulation (128.7 mg kg⁻¹) compared to ZnONPs (NP500, 119.7 mg kg⁻¹), a difference potentially linked to nanoparticle aggregation in the soil matrix limiting root uptake. At the physiological level, a distinct response was observed: while Bulk ZnO stimulated superoxide dismutase (SOD) activity, ZnONPs resulted in a marked reduction (93%), suggesting a shift in the antioxidant strategy toward non-enzymatic mechanisms, such as increased total phenol content. Regarding the volatilomic profile, ZnONPs induced specific metabolic alterations in the green leaf volatile (GLV) pathway, characterized by hexanal accumulation and reduced levels of hexanol and hexyl acetate. Additionally, ZnONPs were associated with lower methyl salicylate (MeSA) emissions, whereas the Bulk treatment increased its relative abundance to 41.7%. Finally, metagenomic analysis revealed that zinc treatments modulated the phyllosphere microbiota, favoring the proliferation of Actinobacteria while decreasing the abundance of sensitive taxa, such as Spirochaetes. Taken together, these findings suggest that ZnONPs act as a distinct metabolic modulator, altering internal physiology and chemical signaling. Full article

Fermented grains (FGs) for Chinese strong-flavor Baijiu (CSFB) serve as both microbial habitats and flavor sources, yet the correlations among fungal communities, physicochemical properties, and volatiles during long-term fermentation remain insufficiently understood. To address this gap, this study employed Illumina HiSeq high-throughput sequencing, physicochemical analysis, and GC-MS for systematic investigation. Fermentation was divided into early, middle, and late stages based on FGs’ physicochemical dynamics and eukaryotic microbial diversity. A total of 9 fungal phyla and 195 genera were detected, with 12 dominant genera (e.g., Thermoascus, Aspergillus, Kazachstania). Forty-seven volatiles were identified, showing increasing diversity and richness. Redundancy Analysis revealed total acids exerted the most significant effect on dominant fungal succession, while network analysis screened 10 key genera (e.g., Mortierella, Trichoderma) pivotal for community structure. Additionally, Trichoderma, Fusarium and other genera correlated with important flavors like 1-butanol and 1-hexanol. This study clarifies the complex interactions in FGs, provides theoretical support for CSFB quality improvement via biofortification or environmental control, and offers a reference for revealing the ecological mechanisms underlying FG microbial community assembly. Full article

The characteristic green-note aroma of Chinese plum (Prunus salicina) is largely defined by C6 aldehydes and alcohols synthesized through the fatty acid pathway involving lipoxygenase (LOX), hydroperoxide lyase (HPL), and alcohol dehydrogenase (ADH). However, the LOX/HPL/ADH gene families and their potential contributions to C6 volatile formation remain poorly characterized in Chinese plum. Here, we integrated genome-wide identification with cultivar-level volatile profiling and RT–qPCR expression analyses to link candidate genes with C6 volatile accumulation. We identified 8 PsLOX, 3 PsHPL, and 13 PsADH genes and classified them into 2, 1, and 3 subfamilies, respectively. Conserved motifs/domains were shared within each family, whereas gene-structure variation suggested functional divergence; segmental duplication was the main driver of family expansion. To explore their functional relevance to aroma biosynthesis, five major C6 aldehydes and alcohols were analyzed in ten cultivars using solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC–MS), revealing substantial diversity in green-note composition. Combined with reverse transcription quantitative polymerase chain reaction (qRT–PCR) expression profiling, low PsADH2.7 expression was associated with high hexanal content, whereas elevated PsLOX5 and PsADH2.2 expression corresponded to increased 1-hexanol accumulation. High 2-ethyl-1-hexanol levels were linked to increased PsLOX4.1 and PsHPL1.3 but decreased PsADH1.2 expression. In addition, (Z)-3-hexen-1-ol abundance showed strong positive correlations with PsLOX3.1, PsHPL1.2, and PsADH2.6 expression. This integrated genomic and expression–metabolite analysis highlights candidate genes potentially involved in C6 aldehyde/alcohol biosynthesis underlying the green-note aroma of Chinese plum and provides genetic targets for aroma-oriented breeding. Full article

Geographical relocation can alter flavor quality in marine crops. Here, the same cultivar of Pyropia haitanensis (“ZHEDONG 1”) was cultivated at six sites spanning northern to southern China, and taste- and odor-active compounds were characterized by LC–MS and GC×GC–TOFMS together with environmental measurements. Inosine monophosphate was identified as the major contributor to umami intensity and showed a strong positive association with nitrate levels. A conserved core aroma profile dominated by heptanal, 2-pentylfuran, nonanal, and 2-ethyl-1-hexanol was consistent across regions, whereas differences in their relative abundances led to distinct regional sensory nuances. Correlation analyses further indicated that phosphate, temperature, and pH shaped volatile composition. These results demonstrate that while P. haitanensis retains a genetically determined intrinsic flavor, environmental conditions modulate flavor intensity and aromatic complexity during cross-regional cultivation. Full article

The flavor and aroma of kiwifruit are largely influenced by the concentration of Volatile Organic Compounds (VOCs). To analyze the volatile profiles and identify characteristic aroma compounds, this study utilized Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) to analyze the aromatic compounds sourced from seven major production regions in China and New Zealand, covering red-, green-, and yellow-fleshed varieties. A total of 77 VOCs were identified, with esters, aldehydes, and ketones as the dominant classes. Significant regional and varietal differences were observed: red-fleshed kiwifruits from Yunnan exhibited high levels of 2-Vinyl-5-methylfuran, Ethyl formate, and 1-Penten-3-one; green-fleshed fruits from Shaanxi were rich in Limonene and Methyl hexanoate, and those from Yunnan were rich in 1-Propanol and 1-Hexanol; and yellow-fleshed fruits from Henan were characterized by Methyl salicylate and 3-Hydroxy-2-butanone. Orthogonal partial least squares discriminant analysis (OPLS-DA) successfully classified kiwifruits by origin and variety, confirming the stability and predictive power of the model (Q2Y > 0.97). This study also elucidated the key metabolic pathways—including lipid oxidation, amino acid degradation, and terpenoid metabolism—underlying the formation of these characteristic VOCs. These findings provide a theoretical foundation for the biochemical regulation of kiwifruit flavor and support the development of origin-tracing and quality-assessment tools based on VOC fingerprints. Full article

Volatile organic compounds (VOCs) are a major occupational concern in polyurethane foam production, where exposure may impact worker health. This study identified key VOCs and evaluated their concentrations across different sections of a polyurethane manufacturing facility. Area (n = 5) air samples were collected during routine full-load production using short-duration active sampling and analyzed by thermal desorption gas chromatography–mass spectrometry (TD-GC-MS). The results revealed marked spatial variability in VOC concentrations, with the curing section showing the highest totals. Dichloromethane (DCM) constituted the dominant VOC in high-emission zones. All measured concentrations of DCM and other regulated substances remained well below European and Polish short-term exposure limits. Quantitative health risk assessment demonstrated that lifetime cancer risk values for DCM and benzene were in the 10⁻⁶ range, far below the regulatory threshold of concern (10⁻⁴). Non-carcinogenic risk indices (HQ) were generally low; however, a markedly elevated HQ was identified for 1-hexanol, 2-ethyl- in the cutting area (HQ = 5.7), indicating a potential localized non-cancer health concern. Overall, existing protective measures appear effective, but additional targeted precautions are warranted in zones with elevated emissions. Enhanced ventilation, strengthened personal protective equipment, and routine air monitoring are recommended to minimize potential health risks. Regular updates of occupational safety standards should reflect evolving toxicological evidence to ensure sustainable protection of workers in polyurethane foam production. Full article