Search Results (203)

The textile industry causes significant environmental problems because of its intensive use of water, energy, and chemicals. The stenter machines, which are commonly used in textile finishing processes, release air pollutants such as odor, volatile organic compounds (VOCs), and total organic carbon (TOC) into the atmosphere during drying and fixing processes carried out at high temperatures. The aim of this study was to investigate odor, VOC, and TOC emissions from the stacks of the stenter machines. In this study, odor, VOC, and TOC parameters were examined in samples from the stacks of stenter machines of nine different plants operating in the textile sector in Bursa, Turkey. The samples were analysed in accordance with EN 13725:2022 standard, EN 13649:2014 standard, and EN 12619:2013 standard for odor, VOC, and TOC parameters, respectively. Acetone, carbon tetrachloride, dibromochloromethane, ethylbenzene, tetrachlorethylene, toluene, and p + m-Xylene were the most common components. The TOC concentrations were determined in the range of 13.89–279.23 mg/Nm³. The odor concentrations were determined in the range of 4113–26,627 OU/m³. Full article

Obolodiplosis robiniae (Haldeman) is a specialist herbivore of Robinia pseudoacacia L., and its infestation is closely associated with tender leaf tissues. The ability of gravid females to recognize suitable host tissues is essential for successful oviposition and subsequent population development. Here, we assessed whether leaf age affects the host-selection behavior of O. robiniae and whether volatile organic compounds are associated with this process. Laboratory oviposition assays were used to compare egg deposition on tender leaves and mature leaves of R. pseudoacacia, and Y-tube olfactometer bioassays were performed to evaluate female responses to odors from the two leaf ages. Volatiles released from healthy tender leaves and mature leaves were collected using dynamic headspace sampling and characterized by thermal desorption–gas chromatography–mass spectrometry. Principal component analysis, orthogonal partial least squares discriminant analysis, and variable importance in projection scores were used to compare volatile profiles between leaf ages. Gravid females deposited significantly more eggs on tender leaves than on mature leaves in both choice and no-choice assays. Females also showed a significant olfactory preference for tender-leaf odors when directly offered a choice between volatiles from tender leaves and mature leaves, with 76.47% of responding individuals selecting tender-leaf odors and 23.53% selecting mature-leaf odors. Chemical profiling identified 28 volatile compounds across the two leaf ages, and their composition and relative abundance differed markedly. Among shared compounds, (Z)-3-hexen-1-ol and α-farnesene differed significantly between tender leaves and mature leaves. Multivariate analyses further identified several candidate compounds contributing to leaf age-related volatile differences. These results indicate that leaf age influences both oviposition behavior and odor-mediated host location in O. robiniae. Leaf age-dependent volatile blends may serve as important chemical cues associated with host selection by gravid females and provide a basis for future studies on volatile-mediated management strategies. Full article

Koji production is a critical process that determines the flavor and quality of the final soy sauce product. However, the complex mechanisms underlying microbial metabolism and the evolution of the physicochemical environment still require further analysis. This study focuses on three parallel koji rooms in an industrialized koji fermentation process. This work tracked the dynamics of physicochemical indices, volatile flavor compounds, and microbial communities over a full 40 h cycle. Data integration and correlation analysis elucidated the close linkage between the microbial community, the fermentation environment, and flavor formation. Koji moisture declined gradually, with faster losses at later fermentation stages. This physiological dehydration arose from microbial metabolic heat, forced aeration and structural loosening of koji, not simple physical evaporation. System pH displayed a typical U-shaped trend across fermentation. Values dropped early, most likely driven by accumulating organic acids, before rising from mid to late fermentation. This pH rebound was tentatively attributed to ammonia release from proteolytic breakdown, which may neutralize acidic compounds. These observations cast doubt on the conventional assumption that organic acid levels may be reliably estimated solely from pH measurements. Physicochemical analysis showed continuous accumulation of amino acid nitrogen (0.6–0.9 g/100 g) and total acidity throughout fermentation. By contrast, reducing sugar concentrations differed across individual koji rooms, presumably owing to divergent microbial adaptation in early fermentation. A total of 77 common compounds were identified, among which 13 key odor-active compounds with OAV ≥ 1, such as 4-vinylguaiacol and 3-methylbutyraldehyde, constitute the characteristic flavor profile of soy sauce starter culture. High-throughput sequencing uncovered a distinct ecological pattern: eukaryotic communities, dominated by Aspergillus oryzae, converged under controlled regulation. While prokaryotic communities differentiated dynamically, driven by spatial heterogeneity in the semi-open fermentation environment. Spearman correlation analysis further indicated potential functional partitioning: high-abundance taxa (e.g., Aspergillus oryzae, Weissella) were predominantly associated with macromolecular substrate degradation, whereas rare low-abundance taxa (e.g., Alternaria) displayed significant correlations with the biosynthesis of key characteristic flavor compounds. This study clarifies the synergistic regulatory mechanisms linking physicochemical conditions, microbial metabolism, and flavor precursor formation during industrial koji production. The findings establish a scientific foundation for optimizing process parameters and achieving standardized quality control in soy sauce manufacturing. Full article

Gas-assisted steam explosion (GASE) disrupts raw material structures and promotes active release, but its effects on the nutritional quality and flavor of edible fungi remain unclear. Therefore, this study assessed the influence of GASE on the nutritional quality and flavor characteristics of Pleurotus eryngii. Using the sample as the raw material, we selected the GASE process parameters through single-factor experiments combined with response surface methodology and confirmation experiments. Subsequently, changes in nutrient contents and volatile/non-volatile flavor profiles were quantitatively characterized under these processing conditions. The results indicated that the selected parameters effectively disrupted the cell wall structure of the sample, resulting in a loose and porous microstructure. Consequently, the levels of protein, polysaccharides, amino acids and vitamins were significantly altered. In terms of flavor, this process modified the relative odor activity values of key aroma compounds, including volatile aldehydes and pyrazines, while also affecting the distribution of non-volatile metabolites. This led to the enrichment of flavor compounds such as nucleotides and their derivatives, and organic acids. This study confirmed that GASE technology can effectively enhance the nutritional quality and flavor characteristics of the mushroom by regulating its microstructure and metabolite composition. Full article

Food loss and waste—FLW—represent a critical global challenge, primarily across postharvest handling, storage, and distribution. Shelf life limitations—arising from microbial activity and proliferation, physicochemical degradation, and environmental interactions—are major contributors to these losses. Intrinsic factors such as pH, water activity, nutrient composition, and biological structure interact with extrinsic conditions including temperature, humidity, gaseous atmosphere, and light exposure, ultimately leading to quality deterioration and consumer rejection. A comprehensive insight into these mechanisms is essential to improve preservation strategies and reduce FLW. This review critically examines the determinants of food shelf life and highlights the strategic role of innovative packaging technologies in mitigating degradation pathways. Particular emphasis is placed on active packaging systems, including commonly studied technologies such as oxygen and ethylene scavengers, carbon dioxide emitters and absorbers, moisture regulators, antimicrobial- and antioxidant-releasing materials, and flavor and odor control systems. Their mechanisms of action, material design, performance factors, and practical limitations are discussed. Innovative packaging technologies actively modulate spoilage, extend shelf life, and preserve both sensory and nutritional quality, moving beyond conventional passive barriers. When combined with optimized supply chains and sustainable materials, these systems can strengthen food system stability and advance global sustainability goals. Full article

Most plant-based essential oil repellent products currently available on the market utilize a “green” approach based on the volatile properties of essential oils. In general, these essential oils contain terpenes, terpenoids, phenylpropanoids or benzenoids that can be used to either (1) eliminate a human’s scent through a process called odor masking, or (2) interfere with an insect’s ability to detect a person’s scent through interaction with both olfactory receptors and odorant binding proteins. Additionally, many of the essential oil blends that have been developed have been shown to exhibit antimicrobial and therapeutic properties. The primary drawback to using essential oil-based repellents is that their protection times vary widely, and typically last only a short period of time due to the volatile nature of the active ingredients, as well as differences in concentration and formulation among products. Encapsulation, nano-delivery systems, and rationally designed blend combinations are being proposed as potential methods to delay the release of the essential oil active ingredients, thus extending the duration of effectiveness of the repellent product. Since essential oils represent complex mixtures, there is a possibility that resistance to the repellent active ingredients could develop differently than it would for single-active agents. However, before such resistance can be assessed, the repellents must undergo extensive safety evaluations, along with standardized efficacy assessments against Environmental Protection Agency (EPA)-approved repellent products, and ultimately, field trials must be conducted in areas where the repellents will be used to prevent vector-borne diseases. In addition to conducting these evaluations, the repellents must comply with existing state and federal pesticide regulations. Full article

In our preliminary work, a clam sauce prepared by fermentation with Aspergillus oryzae 3.042 (AO) exhibited desirable flavor and quality; however, the process was prolonged (exceeding 30 d), and a high salt concentration (6–15%) was necessary to prevent spoilage. Consequently, shortening production cycle and reducing salt content without compromising product quality became a new objective. Enzymatic hydrolysis has long been recognized as an efficient approach in seasoning production, with enzyme efficacy being a key competitive factor. Accordingly, an AO-derived aminopeptidase–protease complex (AOAP) was optimized and prepared as a preparatory step. In this study, AOAP was applied to hydrolyze clam meat to evaluate its potential for producing a seasoning base. A two-step enzymatic hydrolysis process was employed. In the first step, the highest hydrolysis degree (29.1%) was achieved using alkaline protease (AP). The resulting hydrolysate was subsequently subjected to secondary hydrolysis with AOAP, achieving a degree of hydrolysis as high as 49.8%. Sensory evaluation revealed a significant reduction in bitterness and enhancement of umami in the final hydrolysate, a finding corroborated by electronic tongue analysis. Further characterization via LC-MS and amino acid (aa) analysis showed that a substantial number of bitter and umami peptides were released following AP treatment; however, the number of these peptides was markedly reduced after a subsequent AOAP hydrolysis, with concurrent substantial changes in the peptide profile. In the two-step hydrolysate, umami peptides mostly contain 3–10 aa, whereas bitter peptides typically contain only 3–5 aa. The content of free aa increased from 369.17 mg/100 g in the control to 3026.25 mg/100 g in the two-step hydrolysate, half of which were bitter, indicating the debittering efficiency of AOAP. Electronic nose analysis revealed similar flavor profile and characteristic presence of nitrogen oxides in all hydrolysates. GC-MS analysis further demonstrated that, after combined enzymatic hydrolysis, the short-chain aldehydes and ketones responsible for the fishy odor in the raw material almost completely disappeared, while long-chain aldehydes with pleasant aromas were generated. These findings suggest that the secondary hydrolysis step using AOAP can effectively improve the overall flavor profile of the clam hydrolysate, which may support its potential applicability in seasoning production, though further optimization and scale-up validation are needed. Full article

Within the circular economy framework, grape stems, a major winemaking by-product, are increasingly recognized for their potential to modulate wine composition despite some criticalities. This study aimed to investigate fresh and withered stems as both sources of compounds and adsorbents of off-odors. Corvina and Cabernet Sauvignon stems were tested under three conditions: fresh, and 20% and 40% weight loss. Over 14 days of maceration in red wine, the release kinetics of key enological parameters, including pH, ethanol, total phenolics, methoxypyrazines, and C₆ alcohols, were investigated. Concurrently, the adsorption capacity for methanethiol was evaluated. Results indicated that stems significantly influence wine composition by increasing pH and phenolic content while reducing ethanol, with variability associated with the withering treatment. Withered stems showed reduced release of herbaceous pyrazines compared to fresh stems. Stems demonstrated a high affinity for methanethiol, resulting in a significant decrease greater than that observed with commercial enological tannins, known for their ability to reduce reductive mercaptans. This decrease was primarily driven by direct adsorption onto the solid stem matrix, with a secondary contribution from leached soluble compounds. This work provides new insights into the chemical interplay between grape stems and wine, highlighting their valorization potential as a sustainable tool to manage wine composition and mitigate sensory defects. Full article

Atlantic salmon (Salmo salar) is highly perishable during refrigerated storage due to the formation of off-odor volatile compounds that limit shelf life and consumer acceptance. This study investigated the development of off-odor volatiles in Atlantic salmon fillets during refrigerated storage and evaluated how rearing conditions influence storage-induced volatile formation. Salmon reared under warm (20.3 ± 1.95 °C with continuous light) or cool (13.1 ± 0.85 °C with a 12 h light–12 h dark cycle) conditions were harvested, stored at 4 ± 1 °C, and analyzed at 0, 3, 7, 9, and 15 days using selected-ion flow-tube mass spectrometry (SIFT-MS). Refrigerated storage was the primary driver of volatile formation, with lipid-derived aldehydes and alcohols forming early, followed by additional oxidation products as deterioration progressed, and finally, terminal oxidation products. These findings demonstrate distinct temporal pathways of off-odor volatile formation during refrigerated storage, linking early-stage oxidation of polar lipids, mid-stage involvement of neutral lipids, and late-stage accumulation of terminal and microbial products. Protein-derived volatiles exhibited compound-specific behavior, with reactive sulfur- and nitrogen-containing compounds increasing early or mid-storage and microbial metabolites accumulating steadily over time. Environmentally derived off-odor compounds, including geosmin and 2-methylisoborneol, were progressively released during storage as lipid structures degraded. Warm-reared salmon consistently exhibited higher concentrations of lipid- and protein-derived volatiles, indicating greater oxidative and proteolytic susceptibility. Rearing conditions modulate the extent but not the progression of these spoilage mechanisms. This mechanistic understanding provides a basis for targeted strategies to control off-odor volatile compound development and improve refrigerated shelf life and sensory quality of Atlantic salmon. Full article

Rhoptroceros cyatheae (Hymenoptera: Selandriidae) is a dominant herbivorous pest of Alsophila spinulosa in southwestern China, including Guizhou and Sichuan provinces. Infestation by this pest impairs spore reproduction of A. spinulosa and reduces the photosynthetic capacity of host plants. However, the chemosensory genes of R. cyatheae have not been reported, and the molecular basis of antennal detection of host volatile organic compounds (VOCs) is poorly understood. This study aims to screen and identify bioactive VOCs potentially involved in host searching behavior of R. cyatheae, analyze antennal VOC detection patterns, and explore the in vitro binding characteristics of an odorant-binding protein (OBP) involved in olfactory recognition, thereby providing a preliminary theoretical basis for the green management of R. cyatheae. Dynamic headspace sampling, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-electroantennography (GC-EAD) were used to measure antennal electrophysiological responses of R. cyatheae to volatiles from its host A. spinulosa. Y-tube olfactometer assays were conducted to evaluate behavioral responses. For RcyaOBP7, fluorescence competitive binding assays, structural modeling, and molecular docking were integrated to investigate its in vitro binding characteristics with nine selected bioactive VOCs. Nine A. spinulosa volatiles were identified that elicited antennal electrophysiological responses in R. cyatheae, and the sawfly showed behavioral orientation to these VOCs, confirming that its antennae can detect host VOCs. In vitro binding assays showed that RcyaOBP7 exhibited strong binding affinity to p-ethylacetophenone, suggesting its potential involvement in antennal olfactory recognition of this volatile. Specific VOCs released by A. spinulosa are among the signaling molecules detected by the antennae of R. cyatheae. In vitro findings indicate that RcyaOBP7 binds specifically to p-ethylacetophenone, suggesting a possible role in antennal olfactory recognition and behaviors such as host location. However, in vivo functional validation and field trials under ecologically relevant conditions are needed to confirm these roles. This study characterizes the in vitro binding properties of RcyaOBP7 and provides a basis for further research on green management strategies for R. cyatheae based on antennal olfactory signals. Full article

Cooking-related emissions represent a major contributor to indoor air pollution in residential kitchens, producing complex mixtures of volatile organic compounds (VOCs), odor-causing gases, oil vapors, particulate matter (PM_2.5), and combustion-related pollutants (CO and NO_x). In this study, a controlled ozone-assisted oxidation approach was integrated into a recirculating (ductless) domestic kitchen hood equipped with a confined reaction chamber and experimentally evaluated under closed-loop operating conditions where treated air was returned to the indoor environment after post-treatment. A multivariate Response Surface Methodology (RSM) framework based on the Box–Behnken design was employed to quantify and optimize the coupled effects of temperature (20–30 °C), relative humidity (40–60%), ozone dosage (1–3 ppm within the confined reaction zone), and airflow rate (150–250 m³/h) on multi-pollutant removal performance. The results demonstrate that ozone assistance substantially improves the abatement of oxidation-sensitive pollutants, particularly VOCs and odor, while airflow rate strongly governs transport-dominated pollutants such as PM_2.5 and oil vapors. In contrast, CO and NO_x exhibited limited improvement, indicating that ozone-assisted oxidation alone is insufficient for comprehensive control of combustion-related gases under short-residence-time recirculating hood conditions. The main contribution of this work is the implementation of a demand-driven ozone management strategy, supported by dual ozone sensing for reaction-zone control and outlet safety verification, where ozone generation is activated only in the presence of reactive gaseous pollutants and automatically reduced or terminated once pollutant concentrations fall below predefined thresholds, minimizing unnecessary oxidant release. Residual ozone downstream of the reaction stage was continuously monitored to prevent excess ozone return to the occupied zone. Overall, the proposed closed-loop, feedback-controlled ozone-assisted recirculating range hood concept demonstrated device-level reductions in measured VOC/odor signals under controlled conditions, while also highlighting the need for complementary post-treatment components for particle- and combustion-related pollutants. However, the potential formation of secondary oxidation byproducts was not characterized in this study, and therefore the results should be interpreted with respect to device-level pollutant removal rather than comprehensive indoor air quality improvement. Full article

Bactrocera dorsalis (Hendel) is a major fruit-feeding pest that poses a severe and persistent threat to the horticulture industry in tropical and subtropical regions. Methyl eugenol (ME) is a powerful male-specific attractant phytochemical and pheromone precursor that has been widely exploited in lure-and-kill pest management programs. Upon ingestion, ME is metabolized (E)-coniferyl alcohol (E-CF) and 2-allyl-4,5-dimethoxyphenol (DMP), which are stored in the male rectal glands and released during courtship to attract females. Despite its ecological significance, the fundamental molecular mechanism underlying ME perception remains poorly understood. Here, we performed a comparative transcriptomic analysis of ME-responsive and ME-non-responsive male B. dorsalis across four tissues (head, gut, midleg, and wing). A total of 15,727 genes were annotated, of which 970 were associated with odorant-binding proteins (OBPs), odorant receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), and chemosensory proteins (CSPs), as well as detoxification families comprising cytochrome P450s (CYPs), carboxylesterases (CaEs), glutathione S-transferases (GSTs), and uridine diphosphate (UDP)-glycosyltransferases (UGTs), and the stress-related heat shock proteins (HSPs) genes. Differential expression analysis identified 7222, 7763, and 6105 differentially expressed genes (DEGs) in the head, gut, and wings/midlegs, respectively, between ME-responsive and ME-non-responsive males. Notably, CYPs, UGTs, and HSPs involved in detoxification and stress response were significantly downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that CYPs were significantly enriched in metabolic detoxification pathways. These findings reveal a complex molecular interplay between olfaction and detoxification and suggest that ME induces coordinated genetic pathways supporting survival, reproduction, and environmental adaptability. This knowledge provides a foundation for the development of eco-friendly pest management strategies targeting these molecular mechanisms. Full article

A sustainable way to recycle used tires and improve the functionality of asphalt pavements is through the use of crumb rubber modified asphalt (CRMA). However, its application during high-temperature construction raises environmental and occupational health concerns due to the release of significant quantities of odorous and potentially harmful gases. Therefore, this study selected α-Amyl cinnamic aldehyde (ACA) as a deodorant and added it to CRMA at proportions of 0.5%, 1.0%, 1.5%, and 2.0% to prepare DCRMA. A number of common tests, such as softening point, ductility, penetration, Brookfield rotational viscosity, and segregation analysis, were used to evaluate the basic characteristics of the modified asphalt. A self-developed asphalt fume monitoring device was used to quantitatively analyze the changes in VOCs, H₂S gas concentration, and solid particle content in the asphalt fumes to assess the deodorization effect of ACA on CRMA. Furthermore, the deodorization mechanism of ACA on CRMA was explored in depth using microscopic methods, such as fluorescence microscopy (FM) and Fourier transform infrared spectroscopy (FTIR). The findings demonstrated that ACA can increase the softening point and viscosity of CRMA while decreasing its penetration and ductility. The storage stability was optimal at a 1.0% ACA addition. Additionally, as the ACA content increased, the concentrations of VOCs, H₂S gas, and solid particles in the asphalt fumes continued to decrease. FM results indicated that when the ACA content did not exceed 1.0%, it promoted the swelling degree of CR in the asphalt. FTIR results showed that ACA can reduce the characteristic peak intensity of CRMA. This study offers important technical references and practical support for the environmentally friendly use of CRMA. Full article

About 10% of plastic products are recycled worldwide, highlighting the need for technology improvements based on deeper material understanding. In packaging, which holds the highest market share in plastics demand, odor and potential hazards remain critical barriers to high-quality recycling. Conventional characterization relies on chromatography with extensive sample preparation. A gas chromatography system equipped with thermal desorption and dual flame ionization and mass spectrometric detection (ATD-GC/FID-MS) was established to analyze recyclates directly, thereby accelerating technology adaptation and guiding follow-up analyses. For calibration and validation, liquid standards were introduced into TenaxTA-filled tubes via a packed column injector and compared to a loading rig. The injector exhibited losses for higher-molar-mass compounds and solvent-dependent signal shifts. A storage study on compounded recycled polypropylene stored under various conditions showed that samples not frozen in sealed containers should be analyzed within 30 days. Experiments with varying sample geometries demonstrated that higher surface-to-volume ratios increase volatile release and variability in results, highlighting the need for uniform shapes. Applying the method to recycled yogurt cups enables the identification and quantification of contaminants, facilitating optimization of the washing process. Overall, ATD-GC/FID-MS provides a rapid screening tool for recyclate quality control and supports the improvement of recycling technologies. Full article

Wood products made from Manchurian ash are widely used as furniture and decorations, particularly waterborne-coated Manchurian ash (Fraxinus mandshurica Rupr.). However, while waterborne coatings offer less air pollution, their odor emission dynamics under different environmental conditions remain poorly understood. To address these gaps, this study systematically analyzed 28-day volatile organic compounds (VOCs) and very volatile organic compounds (VVOCs) release profiles under controlled temperature, relative humidity, and air exchange rate-to-loading factor ratios (AER/Ls), using thermal desorption–gas chromatography–mass spectrometry/olfactometry (TD-GC-MS/O). Eighteen key odor-active compounds (OACs) were identified, comprising 11 wood-derived and seven coating components, exhibiting eight odor attributes: disinfectant-like, aromatic, tobacco-like, unpleasant, vinegar-like, flowery, sweety, and alcohol-like. The dominant attributes were disinfectant-like and aromatic. The results showed that temperature accelerated release rates and shortened equilibrium time, while increasing concentrations and odor intensity. Relative humidity prolonged equilibrium, with stage-dependent concentration effects, yet consistent odor intensity rise. Higher AER/L reduced equilibrium time and concentrations through dilution-dominated dynamics despite accelerated release rates from increased pressure differentials. These findings indicated that synergistic high-temperature (40 °C)/high-humidity (60% RH) conditions accelerate odorant emission, while optimized ventilation (AER/L 0.5 m³·m⁻²·h⁻¹) ensures effective mitigation. The findings will inform strategies to reduce odor impact and advance eco-efficient finishing technologies for wood products. Full article