Search Results (229)

Liver fibrosis is a chronic disease diagnosed through invasive methods that can worsen patients’ health. Moreover, this disease is diagnosed in terminal stages, when the damage is already widespread and irreversible, which makes it necessary to have minimally invasive diagnostic methods with high performance. The aim was to compare research on non-invasive methods, respiratory footprint, and volatile organic compounds for the diagnosis of liver fibrosis through patient exhalation. Following the PRISMA guidelines, systematic searches were conducted in 13 databases. We could identify 17,454 documents between 2009 and 2022. Inclusion criteria comprised original investigations using Gas Chromatography–Mass Spectrometry (GC-MS), Ion Mobility–Mass Spectrometer (IMR-MS), and e-nose for liver fibrosis diagnosis. We considered the precision, specificity, and sensitivity of each test and the methodological quality of each study according to the PEDro guideline. Seven investigations were included. Four (57%) studies used GC-MS, and two (28.6%) used e-nose. The most commonly used gold standard was liver biopsy, and all studies were of European origin, with only adult populations. Three (42%) studies had a specificity >90%, and five (71.4%) had a sensitivity between 85 and 100%. Isoprene is the most significant and distinguishable biomarker for liver fibrosis diagnosis. Five (71.4%) studies had high methodological quality. GC-MS is the most used technique for detecting liver fibrosis, and isoprene is the most frequent volatile organic compound (VOC) found in the exhalation of patients with liver fibrosis. More studies are needed in areas with high risk and prevalence of hepatic fibrosis. Full article

Teas processed from specialty-colored tea leaves possess distinctive quality profiles shaped by their volatile and non-volatile compounds, which serve as critical metrics for evaluating tea cultivars. In this study, we comprehensively characterized the quality attributes of flat green teas produced from three tea cultivars—green-leaved ‘FDDB’, yellow-leaved ‘ZH2’, and purple-leaved ‘ZJ’—using an integrated analytical approach including sensory evaluation, widely targeted metabolomics, GC-E-nose, and HS-SPME-GC-MS. Sensory evaluation revealed distinct sensory characteristics among teas processed from the three cultivars with different leaf colors. GC-E-nose analysis further confirmed that the aroma profiles of these tea samples could be clearly distinguished based on leaf color. Metabolomic analysis identified a total of 2050 non-volatile compounds, among which 18 amino acids, 5 phenolic acids, and 4 flavonoids were pinpointed as key contributors to the unique taste profiles of infusions from ZH2 and ZJ teas. Additionally, a total of 1100 volatile compounds were detected, with 94, 75, and 90 key aroma-active compounds identified in FDDB, ZH2, and ZJ teas, respectively. Collectively, in this study, systematic analysis revealed significant differences in both volatile and non-volatile chemical compositions across the three tea cultivars. These findings provide a scientific foundation for understanding the processing suitability and quality formation mechanisms of tea cultivars with distinct leaf colors. Full article

Walnut oil is growing in consumer demand due to its rich nutritional profile; however, its fatty acid composition exhibits an imbalanced SFA:MUFA:PUFA ratio (0.13:0.18:1). To improve the fatty acid balance using locally available vegetable oils in Xinjiang, we investigated the effects of blending walnut oil with linseed oil, safflower seed oil, sunflower seed oil, rapeseed oil, peanut oil, and soybean oil on physicochemical indexes, fatty acid composition, and bioactive components. Aroma characteristics were assessed by E-nose and HS-GC-IMS. The results showed that the acid value and peroxide value of the blended oil decreased, while the content of vitamin E and squalene increased inversely. The ratio of ω-6/ω-3 maintain steadily at 4–6:1, and the ratios of SFA, MUFA, and PUFA were close to 0.27:1:1. Significant differences were observed between the aroma characteristics of walnut oil and the blended oil. HS-GC-IMS identified 85 volatile organic compounds (VOCs), among which walnut oil had a higher content of alcohols, aldehydes, and ketones, with 4-hydroxy-5-ethyl-2-methyl-3(2H)-furanone as its characteristic aroma compound. The acetophenone serves as the key aroma component after blending, and the unique flavor components of each base oil (e.g., 4-nonanone in linseed oil, 3-methyl-2-pentanone in rapeseed oil, etc.) exert a synergistic effect after rationing to present a composite aroma characteristic of blended oils, which mainly consists of 3-methylbutyl butyrate and 4-ethylphenol. Full article

This study investigated the comprehensive effects of harvest timing and stir-frying on Ziziphi Spinosae Semen (ZSS) quality using chemical profiling, Caenorhabditis elegans bioassays, and intelligent sensory analysis (electronic nose (E-nose), electronic tongue (E-tongue), and gas chromatography-ion mobility spectrometry (GC-IMS)). Results indicated that delaying harvest to 15 September significantly promoted bioactive accumulation, with total saponins reaching 9.54 g kg⁻¹ at this stage. Stir-frying the optimal raw material further enhanced pharmacological efficacy; spinosin content increased 1.48-fold, and C. elegans motility cessation time significantly shortened from 240 s to 180 s, demonstrating superior sedative activity. Additionally, stir-frying improved the total sensory score from 53.8 to 80.4, characterized by a harmonized balance of bitterness and umami. GC-IMS analysis identified Maillard reaction products, specifically 2-methylpyrazine and 2-methylbutanal as key markers responsible for the distinctive roasted aroma. Consequently, harvesting the fruits of Ziziphus jujuba var. spinosa at physiological maturity, followed by the stir-frying of ZSS effectively enhances its sedative effects and flavor profile. Full article

This study comprehensively analyzed the effects of gamma irradiation (GI) on the flavor profile of aged light-flavor tartary buckwheat Baijiu (LTB) using E-nose, E-tongue, and high-sensitivity headspace–gas chromatography–ion mobility spectrometry (HS-GC-IMS). A total of 30 volatile organic compounds (VOCs) were identified, with concentrations showing significant dose-dependent correlations with GI treatment. Aging alone reduced harsh and pungent VOCs (e.g., 1-propanol, 2-methyl butanoic acid ethyl ester), while GI followed by aging further decreased undesirable compounds (e.g., butanal-D, pyrrolidine) and enhanced beneficial flavor components, such as 1,1-diethoxy ethane-D and butanoic acid propyl ester. Notably, this treatment partially restored 1-propanol, triethylamine, and 2-butanone-M, though their levels remained significantly lower than in newly brewed LTB, achieving a more balanced purity and flavor complexity. The significantly elevated levels of tetrahydrofuran-M/D, 1,1-diethoxy ethane-D, and cyclohexane in GI-treated aged LTB, along with their dose-dependent accumulation patterns, suggest their potential as reliable markers. Multivariate analysis confirmed that all three techniques (E-nose, E-tongue, and HS-GC-IMS) effectively differentiated LTB samples, with strong correlations between E-nose and HS-GC-IMS data, as well as between E-tongue and HS-GC-IMS results. This work provides flavor fingerprints and potential markers for gamma-irradiated LTB identification, while proposing an innovative technical approach for rapid flavor assessment of light-flavor Baijiu. Full article

Thamnaconus modestus (black scraper) is an economically important fish species in Chinese coastal fisheries, yet its pronounced fishy off-odor, primarily attributed to sulfur-containing compounds and trimethylamine (TMA), severely limits consumer acceptance and product diversification. However, a systematic investigation into how different thermal processing methods affect its volatile flavor profile is lacking. This study employed an integrated multi-instrumental flavoromics platform combining sensory evaluation, electronic nose (E-nose), electronic tongue (E-tongue), gas chromatography–ion mobility spectrometry (GC-IMS), and headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS), coupled with chemometric analysis, to systematically characterize the aroma variations of T. modestus subjected to steaming, boiling, deep-frying, and roasting treatments compared with raw samples. A total of 62 (GC-IMS) and 129 (GC-MS) volatile compounds were identified, from which 78 characteristic markers (VIP > 1) and 45 key odorants (OAV ≥ 1) were screened. Thermal processing markedly reduced sulfur-containing compounds and TMA concentrations (raw >> steamed ≈ boiled >> deep-fried > roasted) while promoting lipid oxidation- and Maillard reaction-derived aldehydes and furans. Two distinct flavor modulation patterns were revealed: moist-heat methods (steaming, boiling) generated grassy/fatty notes through moderate lipid oxidation, whereas dry-heat methods (deep-frying, roasting) produced characteristic roasted/nutty notes via synergistic activation of Strecker degradation and Maillard reaction. These findings provide scientific evidence for precise flavor quality control and diversified processing optimization of T. modestus products. Full article

Volatile organic compounds (VOCs) emitted from hardwood papers are associated with cellulose fibers, paper fillers, and the manufacturing process used. Volatiles emitted from samples of office (printing and writing) papers from various brands and countries were analyzed by gas chromatography–mass spectrometry (GC-MS) and an electronic nose (e-nose) based on piezoelectric quartz crystals. Dodecanoic acid 1-methylethyl ester (isopropyl dodecanoate) and nonanal have shown to be the dominant compounds in most of the samples analyzed, regardless of the pulpwood used in paper manufacturing: Eucalyptus globulus, acacia, and birch. 3-Hydroxybutanone was detected only in Spanish papers, suggesting it as a potential marker. Additionally, the content in acetic acid enables the identification of recycled paper. Full article

Drying and storage conditions play a critical role in shaping the quality of aged citrus peel. This study investigated the effects of different processing strategies on the volatile composition, microstructure, and sensory characteristics of five-year-aged Citrus Reticulata ‘Chachi’ Peel (CRP). Four treatments were evaluated using SPME/GC–MS, GC–IMS, electronic nose analysis, sensory assessment, scanning electron microscopy (SEM), and multivariate statistical tools. GC–IMS identified 96 volatile compounds, demonstrating that aging combined with varied drying–storage conditions promoted the formation of diverse aroma-active substances. Terpenes and related compounds predominated, with the indoor-dried and warehouse-stored XH sample showing significantly higher concentrations of key terpenoids and sesquiterpenes, including α-terpineol, γ-muurolene, germacrene, β-selinenol, α-farnesene, and nerolidol. These compounds contributed to enhanced citrus, floral, fruity, and woody notes. Principal component analysis of electronic nose data (93.46% cumulative variance) clearly distinguished XH from other samples. Sensory results supported instrumental findings, indicating stronger fruity and sweet attributes in XH and C, while sun-dried samples exhibited more hay-like characteristics. SEM revealed better structural integrity in indoor-dried samples, potentially facilitating volatile retention. Overall, indoor drying and controlled storage improved aroma complexity and sensory quality, providing a scientific basis for optimized CRP processing. Full article

The increasing diffusion of plant-based milk alternatives poses new challenges at the intersection of food safety and consumer experience, particularly regarding allergen cross-contamination and beverage performance during preparation. Traditional quality control strategies are typically confined to upstream production stages and are unable to address individualized risks and sensory variability at the point of consumption. In this study, we propose an embedded volatilomic sensing approach that combines metal oxide semiconductor (MOX) sensor arrays with lightweight artificial intelligence algorithms to enable real-time, on-device decision-making. The volatilome of four commercially available plant-based milk beverages (oat, almond, soy, and coconut) was characterized using GC–MS/SPME as a reference method, while a MOX-based electronic nose provided rapid, non-destructive sensing of volatile fingerprints. Linear Discriminant Analysis demonstrated clear discrimination among beverage types based on their volatile signatures, supporting the use of MOX sensor arrays as functional descriptors of compositional identity and process-related variability. Beyond beverage classification, the proposed framework is designed to support future implementation of (i) screening for anomalous volatilomic patterns potentially compatible with accidental cow’s milk carryover in shared preparation settings and (ii) adaptive tuning of preparation parameters (e.g., foaming-related settings) in smart beverage systems. The results highlight the role of embedded volatilomic intelligence as a unifying layer between personalized risk-aware screening and sensory-oriented process control, paving the way for intelligent food-processing appliances capable of autonomous, real-time adaptation at the point of consumption. Full article

In this study, 10 popular commercial oat milk samples were analyzed for sensory quality and flavor chemistry using the Ideal Profile Method (IPM), electronic nose (E-nose), and gas chromatography-mass spectrometry (GC-MS). Based on consumer cognitive mapping of ideal products, samples were classified into “Ideal-like” and “Ideal-exceeding” categories. Ideal-like products exhibited light white appearance, pronounced oatiness, moderate sweetness and burntness, and low graininess, presenting a balanced flavor profile, whereas Ideal-exceeding samples surpassed consumer expectations in sweetness or graininess intensity, delivering stronger sensory stimulation. Furthermore, sensory differentiation among categories primarily stemmed from synergistic effects of lipid oxidation levels (e.g., 3,5-octadien-2-one) and physical stability (fiber and protein content affecting particle size distribution). This classification framework reveals that ideal sensory quality can be achieved through diverse physicochemical pathways in commercial oat milk, providing theoretical guidance for product formulation optimization and quality standardization. Full article

Ultrafine dark tea powder (UDTP) was prepared by superfine grinding and sieving through a 200-mesh sieve, and incorporated into cookies to improve their textural properties, sensory acceptability and flavor characteristics. Through single-factor experiments and orthogonal testing, the optimal formulation was determined. The quality of cookies was evaluated by texture analysis, sensory evaluation, electronic nose (E-nose), and gas chromatography-mass spectrometry (GC-MS). Results showed that cookies supplemented with 4 g UDTP per 80 g butter exhibited significantly lower hardness and comparable fracturability, along with higher sensory scores in texture, odor and taste compared to basic butter cookies. E-nose and GC-MS analyses revealed that UDTP enrichment promoted the formation of desirable volatile compounds, particularly aldehydes, ketones, and heterocyclic compounds, which contributed to floral, fruity, roasted nutty, and caramel aromas. This study demonstrates that UDTP can effectively improve both the textural and flavor properties of cookies, providing a viable approach for developing tea-fortified baked products with enriched sensory profiles. Full article

In vitro fecal inoculation coupled with gas chromatography–mass spectrometry (GC-MS) has been used for evaluating fecal deodorants. However, high cost and complex data interpretation limit its routine application. An electronic nose (eNose) offers a rapid, cost-effective alternative. This study aimed to evaluate the eNose as a screening tool for fecal odor compared with solid-phase microextraction gas chromatography–mass spectrometry (SPME GC-MS) and to examine the in vitro effects of fecal deodorant supplements on fecal odor profiles. Feces from ten healthy cats were serially diluted (1:1 to 1:8) and analyzed using both instruments. Four dietary supplements—Yucca schidigera extract (YSE), Quillaja saponaria extract (QSE), fructooligosaccharides (FOS), and oat beta-glucans (OBG)—were tested at concentrations of 0.0, 0.2, 0.4, and 0.8 g/100 mL. The eNose showed comparable performance to GC-MS in discriminating among sample dilutions. In vitro fermentation showed that FOS and OBG significantly increased volatile fatty acid (VFA)-related sensor responses while signals linked to ammonia and sulfur compounds were reduced. QSE had minimal effect, whereas YSE produced moderate changes. The total sensor response intensities did not differ between treatments. These findings indicate that prebiotic supplements exert stronger effects than saponin-based supplements and highlight the potential of eNoses with in vitro fermentation for rapid screening of fecal deodorants. Full article

To assess the impact of developmental stages on the postharvest quality of loquat, fruits at five distinct maturity phases (T1–T5) were systematically analyzed. This study employed a range of analytical techniques to conduct a comprehensive examination of the variations in quality, nutritional content, and volatile compounds of loquat across different developmental stages. Sensory evaluation indicated that the T4 stage achieved the highest score (93.21 ± 1.13), with significant differences observed in a* (6.56–13.08) and b* values (16.91–22.16). Both moisture content (45.45–86.94 g/100 g) and fruit firmness (8.65–3.31 N) exhibited a decline with delayed harvest (p < 0.05). Scanning electron microscopy (SEM) analysis revealed that, as the developmental period progressed, the pores in the loquat cell walls enlarged, and the cellular structure became increasingly relaxed. GC–MS and GC–IMS detected 48 and 47 volatile compounds, respectively. Using orthogonal partial least squares discriminant analysis (OPLS–DA), we identified 14 key compounds that distinguish the five developmental stages. E-nose and E-tongue analyses showed significant changes in the smell and taste profiles of loquats over time, with the T1 stage notably different from later stages. This study offers important insights and guidance on the postharvest quality of loquats at various developmental stages. Full article

The spreading process constitutes a pivotal stage in green tea manufacturing. This study integrated GC-E-Nose with targeted metabolomics to comprehensively elucidate the dynamic changes in sensory characteristics and aroma substances of green tea across varying spreading degrees. Our findings demonstrated that spreading degree significantly modulated green tea’s aroma profile, with lighter degree particularly promoting the development of desirable floral aroma. GC-MS/MS quantification identified 70 volatile compounds, among which 38 exhibited spreading-dependent differential accumulation (VIP > 1.0, p < 0.05). Five key odorants, including indole, β-ionone, nerolidol, cis-jasmone, and β-damascenone, were highlighted as essential contributors to the floral aroma. Molecular docking simulations indicated stronger binding affinities between these five odorants and the olfactory receptor OR1D2 (<−6 kcal/mol), primarily via hydrogen bonding and hydrophobic interactions. These findings indicate that modulating the spreading degree is an effective processing strategy to enhance the development of floral aroma in green tea, offering valuable insights for precision-driven optimization of tea processing protocols. 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