Search Results (139)

Tea-flavor baijiu, in which the aroma combines the tea note and the typical profile of baijiu, has brought a fresh flavor to the market. Yet its flavor evolution during the storage period and the associated changes in volatile compounds remain poorly characterized. To systematically address the flavor profile dynamics during storage, the study evaluated tea-flavor baijiu of varying ages using integrated sensory and instrumental analyses. Through napping with ultra-flash profiling (Napping-UFP) and check-all-that-apply (CATA), the sensory attributes from aroma, flavor, and mouthfeel profiles of tea-flavor baijiu were established, and quantitative descriptive analysis (QDA) was employed to distinguish the distinct sensory profiles among samples with different aging durations. The overall aroma patterns were examined using an electronic nose (E-nose), and the distinction of sample A401 with the longest storage period was notable. Headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS) were used to identify and quantify the volatile compounds, while aging notably altered volatile composition with increased ester levels and reduced alcohol content; hence, the short-aged (one to three years), mid-aged (four to six years), and long-aged (seven and eight years) samples could be easily differentiated. Through the analysis of the data, 12 key odor-active compounds, namely (E)-2-methyl-2-butenal, ethyl caproate, 3-methylbutanal, 2-pentanone, ethyl acetate, ethyl heptanoate, ethyl 2-methylbutanoate, ethyl pentanoate, ethyl butyrate, ethyl hexanoate, ethyl octanoate, and 2,4-di-tert-butylphenol, were identified as major contributors to shifts. Furthermore, Pearson correlation analysis revealed a strong negative association between the accumulation of esters and the intensity of tea aroma in long-aged samples, clarifying the chemical mechanism underlying the diminished tea note in aged tea-flavor baijiu. This study provides new insights into the impact of aging on the flavor profile of tea-flavor baijiu and offers a scientific foundation for improving its production, storage, and quality management. Full article

In Central Europe, the fawning season of roe deer (Capreolus capreolus) directly overlaps with meadow and alfalfa harvest, typically from late May to early June. During these operations, tens or more likely hundreds of thousands of fawns are mutilated by agricultural machinery. To mitigate this unethical mortality, wildlife managers often deploy odor repellents to drive roe deer individuals from high-risk fields before mowing. Therefore, we evaluated repellent efficacy in a paired design. The abundance of roe deer was quantified by drones equipped with thermal cameras before and after repellent application and then compared with untreated control meadows. Results showed high adult abundance that did not differ significantly among treatments. The highest median was paradoxically observed on meadows “after application” (8.25 ind./10 ha), followed by “not treated” meadows (7.92 ind./10 ha), and “before application” (5.72 ind./10 ha). For fawns, differences between treated and untreated plots were likewise non-significant. Their numbers increased over time after application, consistent with the peak of parturition in the second half of May. Overall, the study confirms that the tested odor repellent, when applied according to the manufacturer’s protocol, did not reduce roe deer presence on meadows. This underscores the need to consider alternative approaches, such as the use of thermal-imaging drones combined with the subsequent translocation of detected fawns to safe locations. Full article

Taste and odor (T&O) compounds in freshwater are frequently produced by certain cyanobacteria; however, their occurrence remains difficult to predict. This study examined the temporal and spatial variations in the mibC gene, which encodes a critical enzyme in the biosynthesis of 2-methylisoborneol (2-MIB), by analyzing environmental DNA (eDNA) and RNA (eRNA) in the North Han River, Republic of Korea, from July 2019 to October 2021. Surface water was sampled at twelve sites and analyzed for mibC DNA copy number, RNA expression, cyanobacterial cell density, and 2-MIB concentration using quantitative PCR (qPCR), microscopy, and gas chromatography–mass spectrometry (GC–MS). The mibC gene was present throughout the year, exhibiting peaks from late summer to early winter; higher concentrations typically initiated upstream and subsequently moved downstream. RNA expression was elevated from summer to autumn, rapidly declined following heavy rainfall, and reliably preceded increases in 2-MIB concentrations by 2–4 weeks. RNA levels were strongly correlated with 2-MIB concentrations (r = 0.879, p < 0.001) but showed only a moderate association with Pseudanabaena cell density, whereas DNA demonstrated weaker correlations. More than 95% of total 2-MIB was dissolved, limiting the ability to directly estimate concentrations from eRNA data alone. The results indicate that eRNA monitoring is an effective early warning tool for T&O events. In addition, combining eDNA and eRNA analyses enables a more accurate evaluation of T&O-producing cyanobacteria, presenting practical benefits for proactive management of drinking water. Full article

Herein, we address the peculiar lack of scientific reporting on odor potent chloroanisoles (CAs) in the built environment. We have searched and critically examined sources beyond peer-reviewed scientific journals, namely research conferences, parliamentary records, newspaper articles, and cartoons. We provide evidence that CAs evolved on a large scale in Swedish buildings in the early 1970s and evoked a typical sticky malodor that was attributed to mold and gave rise to the term “mold houses”. The term first appeared in Swedish newspapers in 1978, and the media attention increased rapidly. The malodorous “mold houses” reached the Swedish parliament and led to economic compensation for afflicted homeowners. The “mold houses” became “sick houses” as researchers, predominantly from Sweden, introduced and became world leaders on the “sick buildings syndrome” (SBS). Researchers became aware of the CAs but did not mention them in peer-reviewed articles, just as they did not mention a well-known source of the sticky malodor, namely, legacy preserved wood where CAs were formed through microbial methylation of toxic chlorophenols (CPs). Thus, the mold story from the early 1970s was maintained and prevented the malodorous CAs from becoming recognized as indicators of the presence of hazardous CPs. Our study is the first to report the impact of an indoor malodor, not only on a few people, but on society. Full article

A traditional dairy product from northern Colombia is suero costeño (SC), typically handmade through artisanal processes involving the natural fermentation of raw cow’s milk (RM); it is characterized by a creamy texture and a distinctive sensory profile, with a sour/salty taste and rancid odor. This study aimed to determine the chemical identity (using GC-FID/MSD) of SC and RM samples (from eight locations in the department of Córdoba-Colombia) by analyzing volatile components (trapped by HS-SPME and SDE) and fatty acid content. Consequently, the most notable results were as follows: (a) myristic (7–12%), stearic (12–17%), oleic (13–23%), and palmitic (21–29%) acids were the most abundant constituents [without significant differences among them (p > 0.05)] in both RM and SC fats; these were also expressed as polyunsaturated (2–5%), monounsaturated (26–36%), saturated (59–69%), omega-9 (19–30%), omega-6 (0.5–1.6%), and omega-3 (0.2–1.2%) fatty acids; (b) differences in the composition (p < 0.05) of the volatile fractions were distinguished between RM and SC samples; likewise, the SC samples differed (from each other) in their volatile composition due to the preparation processes applied (processes with raw milk and natural fermentation had less variability); nonetheless, it was possible to determine the volatilome for the artisanal product; and (c) the major components responsible for the chemical identity of SC were ethyl esters (of linear saturated and unsaturated acids, short/medium chains), aliphatic alcohols (linear/branched, short/long chains), aliphatic aldehydes (long chains, >C₁₄), alkyl methyl ketones (long chains, >C₁₁), sesquiterpenes (caryophyllane/humulane types), monoterpenes (mono/bi-cyclics), short-chain fatty acids, and aromatic alcohol/acid, among others. Full article

A detailed description of the components of the CRD technique is presented and applied to the detection of organic esters. These molecules typically have a pleasant smell resembling the aroma of flowers and fruits and are responsible for many distinct odors in plants. They are emitted into the atmosphere by natural sources and human production. The weak absorption spectrum of the fifth vibrational overtone of ethyl, ethyl trimethyl, and tert-butyl acetate are recorded to show the sensitivity of the CRD technique. A description of a compact instrument to be used in the near-IR and visible regions will be presented for measurements of ester detection in the field. Potential chemical reactions of esters induced by visible light absorption in the atmosphere are discussed. Full article

Fragrance is an odorous, volatile substance. Conventionally, encapsulation is performed to improve the preservation and persistence of smells. Typical methods of fragrance encapsulation include interfacial polymerization and the sol-gel method. However, there are issues such as low encapsulation efficiency and difficulty in controlling capsule size and shell thickness. Recently, a method for generating water-in-oil-water (W/O/W)-type microcapsules using microfluidic technology was reported. This made it possible to achieve high encapsulation efficiency and excellent control of the capsule diameter and shell dimensions. However, because this method involves a preliminary dispersion process for fragrance, the production process is more complicated than that of microcapsules using general microfluidic technology. In this study, we used a method for generating oil-in-water-in-oil (O/W/O)-type microcapsules in a microchannel with partially controlled wettability and achieved the generation of monodisperse fragrance-containing microcapsules with a hydrophilic polymer shell without the need for a preliminary dispersion process. Full article

In this study, the impacts of water-bath reheating (WR), steam reheating (SR), air-frying reheating (AR), roasting reheating (RR), and microwave reheating (MR) on the physicochemical properties, oxidation, and flavor profiles of crispy chicken (CC) were investigated. The results revealed that the pH of CC was significantly reduced after reheating (p < 0.05). The AR samples had a slight change in L* and the highest springiness. The RR samples had the highest degree of lipid and protein oxidation. In addition, WR, AR, RR, and MR treatments effectively increased the contents of umami-related amino acids. Glu and Cys were typically the taste-active amino acids in CC. AR contributed to increasing the response values of umami and richness. As shown by the electronic nose and Gas Chromatography–Mass Spectrometry (GC-MS) analysis, 41 volatile compounds were obtained in CC. AR could efficiently increase the contents of nitrogen oxides and methyl compounds. Meanwhile, the content of trans-.alpha.-bergamotene, nonanal, and copaene were significantly increased after the AR process (p < 0.05). According to the results of analysis of variance (ANOVA), odor activity value (OAV), and variable importance in projection (VIP), anethole was considered the key differential flavor-active compound. Overall, AR was superior to other reheating methods in CC, with better texture and various flavor characteristics. This study provides a reference for choosing reheating technology for pre-cooked chicken products. Full article

Collagen is a structural protein found in the connective tissues of terrestrial and marine animals. Its diverse functional attributes span its applications in several industries, including food, supplements, cosmetics, and pharmaceuticals. Typically derived from mammalian sources, collagen and its derivatives, including gelatin and collagen peptides, are essential for the food and supplement industries. Recently, marine collagen has emerged as a viable mammalian collagen alternative due to its unique functionality and sustainability. Marine vertebrates and invertebrates are reliable sources of marine collagen. Some marine organisms are promising sustainable sources of collagen for nutritional applications. Recent research highlights significant advances in marine collagen extraction, processing, and novel applications. Hence, recent interest has propelled research in identifying novel collagen sources and advancing technologies to produce marine collagen-based products. Considering the recent scientific interest in marine collagen, this review provides an overview of recent progress in marine collagen production, including novel sources, innovative processing technologies, nutritional and functional properties, safety and quality control, current challenges, and future research directions. The review highlights certain challenges, including unpleasant odor, flavor, color, insufficient supply, and inconsistent quality of marine collagen. Future research should focus on increasing the collagen extraction yield, improving the smell and flavor, and developing novel delivery systems to increase bioavailability and functionality. Full article

Ensuring safe drinking water is a global priority, with pathogen control being an essential aspect. Chlorine disinfection is widely adopted for its affordability and potent antimicrobial effects. However, certain bacteria, known as chlorine-resistant bacteria (CRB), can still survive in water systems with residual chlorine, posing risks to water quality and distribution systems. Their emergence, ironically, can be partially attributed to the very application or increased dosage of chlorine disinfectants in certain cases, which unintentionally promoted the selection and adaptation of CRB in the environment. Despite their significance, research on CRB remains fragmented, with few systematic reviews or bibliometric analyses. Thus, this study addresses the gap by analyzing 1367 publications (1984–2025) regarding CRB in drinking water supply systems (DWSSs) using CiteSpace. Important aspects including typical species, potential risks, resistance mechanisms, and inactivation methods are reviewed. Contributions from key countries/institutions/journals/authors are also examined. More importantly, overlooked issues like CRB’s impact on taste and odor (T&O) issues in water and their molecular resistance mechanisms are also highlighted. The identification of these gaps in CRB research motivates further studies on their hazards, intrinsic mechanisms and control, which would hopefully help with the delivery of high-quality, safe drinking water worldwide. Full article

Hemp seed oil is nutritious. Besides cannabinoids, it has a higher Omega-3 fatty acid content, making it an ideal and healthy edible oil. Roasting is a key factor affecting the flavor of hemp seed oil. In this study, solvent-assisted flavor evaporation (SAFE) combined with gas chromatography–mass spectrometry (GC-O-MS) was used to analyze the volatile compounds of hemp seed oil after the hemp seeds were roasted at different temperatures (120 °C, 140 °C, 160 °C, 180 °C). α-pinene, (1S)-(1)-β-pinene, myrcene, and (E)-β-ocimene, which are typical odorants for herbs and fresh flavors, had an active odor value (OAV) ≥ 1. The sweet, nutty, and toasty flavors became more pronounced as the temperature increased. 2-pentylfuran provided the caramel flavor, and 2,5-dimethylpyrazine, 2-ethyl-6-methylpyrazine, and 2-ethyl-5-methylpyrazine provided the toasty flavor. The combination of sensory evaluation and data analysis was effective in differentiating the odors of hemp seed oil extracted at different temperatures. Reconstitution and deletion experiments showed that these odorants could mimic the overall aroma profile. This article provides a theoretical basis for the effect of over-roasting on the flavor of hemp seed oil. Full article

Mammals, including humans, sense smell by the responses of odorant receptors (ORs) to odor molecules. We have developed an effective method to identify novel antagonists capable of suppressing the pungent odor of cat urine by targeting specific ORs. Since odors are typically complex mixtures of multiple volatile compounds, olfactory perception can vary depending on the composition. We analyzed the response of ORs to cat urine odor using vapor stimulation assays to identify the responding ORs. Gas chromatography–mass spectrometry was then performed to identify compounds eliciting responses from these ORs. Trace-amine-associated receptor 5 (TAAR5) demonstrated a significant response associated with the odor intensity of cat urine, identifying trimethylamine as a major contributor to the strong odor. From hundreds of candidate compounds, we identified several novel antagonists that exhibited greater efficacy than a known TAAR5 antagonist. These compounds not only reduced the responses of TAAR5-expressing cells to cat urine odor but also significantly reduced odor intensity and improved sensory pleasantness in human tests. Our findings suggest that targeting ORs responsive to specific odors, without isolating their individual components, is a promising strategy for developing deodorizing agents against complex malodors like cat urine odor. This study emphasizes the value of using real odor mixtures to enhance our understanding of odor perception. Full article

Euglena gracilis is a microalga that has great promise for the production of biofuels, functional foods, and bioactive compounds, and mutagenesis and effective screening methods are required to develop Euglena strains that have industrial use. Ethyl methanesulfonate (EMS) is a widely used mutagen, but is highly lethal to Euglena at typical concentrations. In the present study, low-concentration, long-time EMS exposure combined with serial treatment was introduced for generating Euglena mutants. We then used screening protocols to select cells with altered motility or pigmentation, and isolated two distinct strains of Euglena: Mutant 333 and Mutant 335. Mutant 333 showed increased motility but exhibited a decreased differentiation rate and reduced paramylon content (13.5%), making it unsuitable for industrial applications. However, Mutant 335, which had a deficiency of chlorophyll, had a high paramylon content (31.62%) and a mild and pleasant odor profile due to decreased concentrations of certain volatile compounds, with confirmation by GC-MS analysis. The Mutant 335 strain is suitable for the production of functional food products and renewable jet fuel. Full article

The ORA (olfactory receptor class A) gene family in teleosts is related to the V1R (vomeronasal 1 receptors) family in mammals and plays a key role in odor detection. Although ORA genes have been identified in several teleosts, their characteristics in mandarin fish (Siniperca chuatsi) have not been explored. In this study, we conducted a comprehensive genomic analysis of the mandarin fish and discovered a complete ORA gene family consisting of five members located on chromosome 2 (ORA1, ORA2, ORA3, ORA4) and chromosome 16 (ORA6). Phylogenetic, synteny, and gene structure analyses revealed typical exon–intron conservation with strong evidence of purifying selection. Tissue expression analysis showed distinct expression profiles for each ORA gene, with some showing sexual dimorphism in specific tissues. The expression of ORA1 and ORA2 in the olfactory epithelium exhibits sexual dimorphism, while ORA3 shows sexual dimorphism in the brain. In situ hybridization confirmed that ORA1, ORA2, ORA3, and ORA6 are expressed in the microvillar sensory neurons of the olfactory epithelium, while ORA4 is expressed in crypt cells. Additionally, molecular docking simulations indicated that the five ORA proteins have a high binding affinity with seven bile acids (LAC, GLAC, CA, TLCA, 3-KLCA, 7-KLCA, and 12-KLCA), with ORAs showing stronger binding affinity with LCA and CA. This study comprehensively characterizes the ORA gene family in mandarin fish, examining its phylogeny, synteny, gene structure, and selection pressure. Furthermore, we found that each ORA displays a distinct expression pattern across multiple tissues, with notable sexual dimorphism, and shows potential binding interactions with specific bile acids and pheromones. Our findings provide valuable insights that enhance the overall understanding of fish ORAs and their potential functions. Full article

The beet webworm, Loxostege sticticalis, is a typical migratory pest. Although miRNAs participate in many physiological functions, little is known about the functions of miRNAs in olfactory regulation. In this study, 1120 (869 known and 251 novel) miRNAs were identified in the antennae of L. sticticalis by using high-throughput sequencing technology. Among the known miRNAs, 189 from 49 families were insect-specific, indicating that these miRNAs might play unique roles in insects. Furthermore, based on the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, we found that 3647 and 1393 miRNAs were associated with localization and the regulation of localization, respectively, and 80 miRNAs were enriched in the neuroactive ligand–receptor interaction pathway. These miRNAs might be involved in the olfactory system of L. sticticalis. Notably, qRT-PCR showed that most of the tested miRNAs presented similar expression patterns compared with the RNA-seq data and that miR-87-3, novel-miR-78, and novel-miR-142 were significantly differentially expressed in the antennae of males and females. In addition, 21 miRNAs were predicted to target 23 olfactory genes, including 10 odorant-binding proteins (OBPs), 3 chemosensory proteins (CSPs), 4 odorant receptors (ORs), 1 ionotropic receptor (IR), and 5 gustatory receptors (GRs). The olfactory-related miRNAs exhibited low-abundance transcripts, except undef-miR-55 and undef-miR-523, and gender-biased expression was not observed for olfactory-related miRNAs. Our findings provide an overview of the potential miRNAs involved in olfactory regulation, which may provide important information on the function of miRNAs in the insect olfactory system. Full article