Search Results (931)

The quality and flavor of vine tea are largely determined by its processing stages, which markedly influence its physical attributes and volatile organic compounds. Elucidating the dynamic changes in physicochemical and aromatic properties throughout processing is, therefore, essential for guiding optimized processing techniques and developing high-quality vine tea products. However, the specific effects of individual processing stages on quality attributes remain poorly understood. In this study, we combined assessments of color and physical properties with untargeted metabolomics, headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), relative odor activity value (ROAV), and gas chromatography–olfactometry (GC-O) to identify key compounds contributing to vine tea quality. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were further applied to identify characteristic metabolites associated with aroma and flavor differentiation. A total of 280 volatile organic compounds were identified, among which 14 key VOCs (ROAV ≥ 1, aroma intensity ≥ 0.5) exhibited significant dynamic variation across processing stages. Notably, compounds such as β-ionone, β-myrcene, nonanal, and hexanal displayed higher ROAVs and strong aroma intensities (AI ≥ 1.0), indicating their substantial contribution to overall aroma. Furthermore, the metabolic transformation pathways—primarily including fatty acid degradation and carotenoid cleavage—and the content changes of key aroma-active compounds were inferred across different processing stages. Based on the differential accumulation patterns of the identified volatile markers, the possible involvement of fatty acid degradation and carotenoid cleavage pathways was inferred. Drying and fixation emerged as critical steps for vine tea aroma development, while the non-enzymatic degradation of fatty acids was potentially associated with the formation of its aroma characteristics. This study provides insights that may inform future efforts toward processing optimization and quality improvement of vine tea. Full article

Chinese steamed bread (CSB) is an important fermented wheat product, but controlled strategies for modulating its volatile profile remain limited. This study evaluated defined composite sourdoughs comprising Wickerhamomyces anomalus CRFSZY16 or Kluyveromyces marxianus FYY7 in combination with Lactiplantibacillus plantarum SDgsM3 for CSB production using the direct fermentation method (DFM) and the refrigerated sponge-dough method (RSDM). Technological stress tolerance, preliminary safety-related phenotypes, acidification capacity, volatile organic compounds (VOCs), multivariate profiles, and specific volume were assessed. SDgsM3 showed dough-relevant stress tolerance and rapid acidification, while both yeasts tolerated moderate fermentation stresses. Headspace solid-phase microextraction coupled with gas chromatography-triple quadrupole mass spectrometry (HS-SPME-GC-TQ-MS) revealed stage-dependent remodeling of volatile profiles from mature sourdough to fully proofed main dough and final CSB. RSDM selectively modified representative alcohols, aldehydes, furans, ketones, and esters rather than uniformly increasing all VOCs. In the final CSB, the K. marxianus-based RSDM system showed relatively higher levels of 3-methyl-1-butanol, whereas the W. anomalus-based RSDM system showed relatively higher levels of hexanal, nonanal, 1-hexanol, and 2-pentylfuran. Composite sourdough treatments also yielded specific volumes of 2.56–2.66 mL/g versus 2.44 mL/g for the commercial yeast control. These findings demonstrate strain- and process-dependent modulation of CSB volatile profiles and support flavor-oriented composite sourdough design. Full article

Off-odor development during retort sterilization limits the sensory quality of canned Antarctic krill, but measurements in whole krill cannot distinguish intrinsic fatty acid oxidation from matrix-dependent odor expression. To separate these effects, six major fatty acids (C14:0, C16:0, C16:1, C18:1, eicosapentaenoic acid [EPA], and docosahexaenoic acid [DHA]) were examined in a three-tier thermal oxidation model comprising fatty acid-only, lipid-depleted krill matrix, and complete krill meat systems heated at 115 °C for 36 min. Volatile profiles were characterized by gas chromatography–ion mobility spectrometry (GC–IMS) and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS), together with peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), odor activity values (OAVs), sensory evaluation, and exploratory cross-tier correlation analysis. In the fatty acid-only model, EPA and DHA showed the highest POVs (5.26 ± 0.53 and 4.96 ± 0.57 meq/kg), whereas C16:1 and C18:1 produced broader volatile profiles. After matrix incorporation, these patterns changed: C18:1 supplementation was associated with a pronounced aldehydic profile, whereas DHA- and EPA-supplemented complete krill meat showed the highest TBARS values (3.37 ± 0.40 and 3.12 ± 0.37 mg MDA/kg) and high fishy odor scores (6.21 and 5.95). Total OAV was not significantly associated with fishy or oxidized odor, whereas (Z)-4-heptenal, (Z)-1,5-octadien-3-ol, 1-penten-3-ol, and trimethylamine showed closer sensory associations. Thus, intrinsic oxidation potential did not directly predict off-odor intensity; sensory deterioration was more closely related to the matrix-dependent expression of selected potentially odor-active compounds than to fatty acid unsaturation or total OAV. Full article

Mulberry leaf tea (MLT) has gained increasing attention as a functional beverage; however, its aroma quality evaluation remains limited due to insufficient characterization of volatile profiles and aroma-active compounds. In this study, the volatile compositions of ten commercial MLT products were systematically investigated using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS). A total of 123 volatile compounds were identified and classified into alcohols, aldehydes, ketones, esters, hydrocarbons, terpenoids, and other groups, with considerable variations observed among commercial products. Odor activity value (OAV) analysis revealed that 45 compounds exhibited OAV values ≥ 1, indicating their potential contribution to MLT aroma characteristics. Terpenoid and norisoprenoid compounds, including linalool, trans-β-ionone, trans-β-damascenone, and β-ionone, showed high odor activity and were associated with floral, fruity, and woody notes. Partial least squares discriminant analysis (PLS-DA) differentiated commercial MLT products, and five volatile compounds (limonene, p-cymene, eucalyptol, trans-β-ionone, and benzeneacetaldehyde) were identified as potential discriminative markers. This study provides comprehensive insights into the volatile profiles of commercial MLT products and identifies aroma-active compounds for aroma evaluation and product differentiation. Full article

Background: Wampee (Clausena lansium (Lour.) Skeels) is an understudied Rutaceae crop native to southern China, whose fruit features a complex aroma profile with simultaneous sour, sweet, bitter and astringent notes. Although bioactive compounds including flavonoids, alkaloids and volatile oils in wampee fruit have been partially characterized, the tissue-specific metabolic and transcriptional basis underlying its distinctive aroma formation remains largely unclear. Methods: We performed an integrated volatile metabolomic and transcriptomic analysis on the pericarp (peel) and flesh of wampee fruit across three cultivars (Shanyellowpi, Heijingang, Bingtangxin). Volatile metabolites were profiled via headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and transcriptome profiles were generated by RNA-Seq. Multi-omics integration was conducted using Procrustes analysis, gene–metabolite correlation network construction and weighted gene co-expression network analysis (WGCNA). Results: A total of 288 volatile metabolites were identified, representing the most comprehensive volatile inventory for C. lansium reported to date. Principal component analysis and partial least squares discriminant analysis revealed distinct volatile profiles between pericarp and flesh; terpenoids were the dominant chemical class, accounting for 71.56–91.48% of total volatiles in pericarp and 61.88–67.22% in flesh. Notably, organoheterocyclic compounds were significantly enriched in Shanyellowpi flesh (40.45%), forming a cultivar-specific metabolic signature absent in the other two cultivars. Transcriptomic analysis showed that phenylpropanoid biosynthesis was the most significantly enriched pathway among differentially expressed genes, followed by monoterpene biosynthesis and sesquiterpenoid biosynthesis. Procrustes analysis demonstrated a strong global concordance between the two omics layers (M² = 0.535, p < 0.001). Gene–metabolite correlation networks identified terpene synthase (TPS) genes (HP075360, HP217350) and oxidoreductase genes (SOD1, GST, 10HGO) as candidate co-regulators of terpenoid biosynthesis. WGCNA further prioritized TPS genes, cytochrome P450 genes and MYB transcription factor genes as key regulators driving volatile metabolic divergence between tissues. Conclusion: This study provides a comprehensive volatile and transcriptomic atlas of wampee fruit, and identifies tissue-specific and cultivar-specific metabolic signatures as well as their candidate regulatory genes. These findings advance our understanding of quality differentiation in Rutaceae fruits and lay a foundation for molecular breeding and flavor improvement of wampee. Full article

This study investigates the antioxidant efficacy and selectivity of a quercetagetin-rich extract (QG, 89% purity) from Tagetes erecta in soybean oil under accelerated storage conditions (65 °C, 56 days). Using gas chromatography–mass spectrometry (GC-MS) fatty acid profiling, Headspace Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS) volatile analysis, and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) chemometrics, QG at 200 ppm was compared against a solvent control and propyl gallate (PG). QG preserved polyunsaturated fatty acids 5.2-fold more effectively than the control (p < 0.01), though it was less effective than PG in terms of overall Polyunsaturated Fatty Acid (PUFA) preservation. OPLS-DA-VIP analysis identified hexanal, hexanoic acid, and (E)-2-nonenal as preferentially suppressed volatiles (inhibition rates: 74.2%, 100%, and 81.2%, respectively), exceeding the average total volatile reduction (65.7%). A quantitative Selectivity Index (SI) combined with kinetic analysis supported preferential—rather than non-selective—inhibition of specific oxidation endpoints. Structure–activity relationship analysis suggested that the selectivity of the QG-rich extract may be associated with the catechol B-ring and unique 6-hydroxyl substitution of quercetagetin, its major component. The extract’s purity corresponds to a registered feed additive (Ministry of Agriculture and Rural Affairs (MOA) No. 618, 2022), ensuring industrial applicability. These findings establish the quercetagetin-rich extract as a promising selective natural antioxidant for PUFA-rich oils. Full article

This preliminary within-animal study focuses on the comprehensive characterization of pork jowl (PJ) by comparing it with pork belly (PB), Boston butt (BB), and spare ribs (SR) collected from the same ten castrated Duroc × Landrace × Yorkshire (DLY) pigs; headspace volatile analysis used a matched subset of six pigs. Instrumental quality, proximate composition, amino-acid and fatty-acid profiles, low-field nuclear magnetic resonance (LF-NMR) water distribution and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS) volatile profiles were evaluated. PB exhibited the lowest shear force, hardness, and chewiness. Across the four pork cuts, crude protein content ranged from 16.87% to 18.10%, whereas crude fat content ranged from 13.03% to 22.20%. BB had the lowest crude fat content (13.03%) and relatively high protein (18.10%) and amino-acid contents. PJ showed highest content of monounsaturated fatty acids (MUFAs) and the lowest numerical atherogenic (AI) and thrombogenic indices (TI), but also the highest n-6/n-3 polyunsaturated fatty acids (PUFA) ratio. LF-NMR showed that PJ had the highest T₂₃ and P23 values, consistent with its higher cooking and centrifugal losses. Sixty-five headspace volatile compounds were tentatively identified under the standardized 80 °C HS-SPME conditions. OPLS-DA differentiated the four cuts, and ten compounds meeting the combined criteria of VIP > 1, q < 0.05, and OAV > 1 were retained as candidate discriminant aroma-relevant compounds. Overall, the four cuts exhibited distinct quality profiles: PJ combined a MUFA-rich lipid fraction with greater free-water mobility and water loss, PB showed the greatest instrumental tenderness, BB had the lowest crude fat content and relatively high protein and amino-acid contents, and SR exhibited the greatest headspace volatile abundance. The data provide a reference for cut-specific utilization of pork raw materials. Full article

This research investigated the effects of salt concentration on the fermentation of watermelon soybean paste. Three experimental groups were constructed with gradient salt concentrations, and multi-dimensional analyses were performed on physicochemical properties, volatile aroma profiles, and microbial community succession throughout the fermentation process. Group X (lowest salt) exhibited the highest total acid (34.49 g/kg) and lowest pH (p < 0.05) after 60 d. Using headspace gas chromatography time-of-flight mass spectrometry (HS-GC-TOF-MS), a total of 97 volatile compounds were identified, of which 18 were defined as key flavor compounds (relative odor activity value (ROAV) > 0.1 and variable importance in projection (VIP) > 1). High-throughput sequencing demonstrated that Proteobacteria and Firmicutes represented the core bacterial communities while Ascomycota emerged as the dominant fungal phylum. The Shannon diversity index for bacteria ranged from 4.28 to 5.47 across groups. Aspergillus relative abundance in Group X decreased from 75.30% (30 d) to 43.17% (60 d). Group X was distinctly separated from Y and Z in PLS-DA and PCoA analyses. Aspergillus exhibited significant positive correlations with eugenol and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (p < 0.05). These findings provide an integrated understanding of the associations between volatile compound evolution and microbial succession during natural fermentation, providing a basis for further investigation and process optimization. Full article

Huangshui (HS), fermented grains (FG), and pit mud (PM) are closely connected during the fermentation of Nongxiangxing baijiu (NXB); however, the contribution of HS to the differences in flavor profiles across PM, FG, and distilled baijiu has not been fully elucidated. Herein, instrumental techniques of electronic nose (E-nose), headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS), and headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) were used to compare the volatile profiles of HS, FG, PM, and two quality grades of NXB. E-nose analysis revealed that PM exhibited stronger signals related to sulfur-containing, organic, and terpene-associated compounds. Gas chromatography indicated that special-grade baijiu had a more favorable ethyl caproate/ethyl lactate ratio than superior-grade baijiu. Furthermore, HS-GC-IMS revealed different volatile profiles of the samples. Up to 183 volatile organic compounds (VOCs) were identified via HS-SPME-GC-MS, with esters and acids being the dominant classes. Multivariate analysis showed close relationships among HS, FG, and PM, and 35 VOCs were identified as important discriminatory compounds. These results suggest the differences and similarities in VOCs among the HS, FG, PM, and NXB samples, indicating that HS is chemically associated with both FG and PM. This study provides useful insights into HS utilization and quality regulation of NXB through the effective management of HS. Full article

Green (Zanthoxylum schinifolium, ZSEO) and red (Zanthoxylum bungeanum, ZBEO) Sichuan pepper essential oils are widely used spices whose characteristic aromas differ markedly, yet a systematic comparison of their volatile fingerprints and aroma-active compounds is still lacking. To address this, the two essential oils were characterized and compared by combining headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) and gas chromatography–olfactometry–mass spectrometry (GC-O-MS). HS-GC-IMS detected 94 volatile signals; multivariate analysis clearly separated the two oils (R²Y = 0.993, Q² = 0.986) and identified 40 differential markers including 37 aroma-active compounds, with ZSEOs enriched in minty and green-note compounds like isomenthone and ZBEOs in woody, ester and acid compounds such as bornyl acetate. GC-O-MS identified 37 aroma-active compounds, of which linalool was the most prominent odorant in both Eos; a total of 27 were shared, while four and six were unique to the green and red EOs, respectively. Cross-referencing the two datasets showed that volatile abundance and odor contribution were not always concordant. The combined approach clarifies the chemical basis of the aroma difference between the two species and offers a transferable strategy for linking volatile fingerprints to perceived aroma in Zanthoxylum essential oils. Full article

This study investigated quality traits and volatile organic compounds (VOCs) in two winter wheat varieties with different gluten types (Xinliang 169, medium-strong gluten, and Xinliang 607, medium-weak gluten) across five grain-filling stages (5, 10, 20, 30, and 40 days after anthesis, DAA) under heated headspace conditions (80 °C). During grain filling, moisture and total soluble sugar (TSS) decreased significantly, whereas hardness, thousand-kernel weight (TKW), and starch content increased significantly. Protein followed a typical “high–low–high” pattern. Using headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) and headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS), 80 and 125 VOCs were detected, respectively. A total of 19 preliminarily prioritized candidate odorants (e.g., 1-penten-3-one, 2,3-butanedione, and 3-methylbutanal) were screened using orthogonal partial least squares discriminant analysis (OPLS-DA, VIP > 1) and relative odor activity value (ROAV ≥ 1). Based on literature odor descriptors, the aroma profile shifted from green, malty notes during early grain filling to waxy, fatty, and grain-like notes during late grain filling. XL169 was characterized by grassy-green, malty, and fatty grain-like notes, whereas XL607 was dominated by creamy, buttery, and sweet-fruity woody notes. Correlation analysis revealed significant correlations between high-priority candidate odorants (2,3-butanedione, (E)-2-octenal, and 3-hydroxy-4,5-dimethyl-2(5H)-furanone) and quality traits (starch, TSS, and protein). These exploratory findings provide a preliminary reference profile for understanding how grain filling affects wheat VOCs. Full article

Volatile fingerprints provide useful information for characterizing Astragali Radix (AR), a food–medicine homologous plant material, but differences among wild, wild-simulated, and cultivated samples remain unclear. In this study, 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 integrated with multivariate analysis and interpretable machine learning to characterize volatile profiles and identify candidate discriminatory compounds in 117 AR samples from different cultivation patterns. HS-SPME-GC–MS tentatively identified 29, 34, and 45 volatile compounds in wild, wild-simulated, and cultivated samples, respectively. Esters were the predominant class in all groups, although the relative abundance of esters and the overall chemical-class composition varied among cultivation patterns. HS-GC–IMS tentatively identified 57, 50, and 55 compounds, respectively, comprising mainly low-molecular-weight aldehydes, alcohols, and ketones and thereby providing complementary volatile fingerprint information. Partial least squares discriminant analysis (PLS-DA) showed that the volatile fingerprints captured cultivation-pattern-associated differences, with the HS-GC–IMS model showing clearer group separation. Random forest, support vector machine, and CatBoost models were further constructed using the HS-SPME-GC–MS profiling results. By integrating variable importance in projection (VIP) and SHapley Additive exPlanations (SHAP) values, γ-hexalactone, methyl eugenol, methyl (9Z,11E)-octadeca-9,11-dienoate, eugenol, and ethyl linoleate were selected as candidate discriminatory compounds. Based on the HS-GC–IMS results, 1-octen-3-one, pentyl acetate, (Z)-2-penten-1-ol, 2-heptanone, and the monomeric signal of 2-ethyl-6-methylpyrazine were also identified as candidate discriminatory compounds. These compounds may be related to fatty acid-derived metabolism, aromatic secondary metabolism, and terpenoid-related processes. The integration of two complementary volatile-analysis platforms with VIP- and SHAP-based interpretation provided broader coverage of volatile features and improved the interpretability of candidate-compound screening. These findings provide an interpretable analytical workflow and candidate discriminatory compounds that may support future rapid screening, cultivation-pattern authentication, and volatile-profile-based differentiation of AR, pending independent external validation. Full article

The spotted-wing drosophila, Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae), is an invasive pest causing substantial economic losses in berry production worldwide. Reliable monitoring is essential for effective integrated pest management; however, information on the field performance of locally produced vinegar-based attractants remains limited. This study compared the attractiveness of four vinegar-based attractants (homemade grape vinegar, homemade hawthorn vinegar, homemade apple vinegar, and commercial apple vinegar) for monitoring D. suzukii in blackberry (Rubus spp.) and blueberry (Vaccinium spp.) orchards in southeastern Türkiye during the 2023 and 2024 growing seasons. In addition, the volatile organic compound (VOC) profiles of the attractants were characterized using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC–MS). A total of 80,571 adult flies were captured during the study. Significant differences among attractants were detected in all host plant–year combinations (one-way ANOVA, p < 0.001). Generalized linear mixed model analysis further demonstrated significant effects of the host plant, attractant type, sampling week, and year on weekly trap captures (p < 0.05). Homemade grape vinegar consistently produced the highest trap captures, whereas commercial apple vinegar showed the lowest trapping performance. Fourteen volatile compounds belonging mainly to carboxylic acids, alcohols, esters, aldehydes, and monoterpenes were identified, revealing differences in the volatile profiles of the evaluated attractants. Overall, homemade grape vinegar proved to be the most effective vinegar-based attractant under the conditions of this study and represents a practical, low-cost option for monitoring D. suzukii in berry orchards. Further studies incorporating replicated chemical analyses and behavioural bioassays are needed to clarify the contribution of individual volatile compounds to insect attraction. Full article

The lipoxygenase (LOX) pathway plays a crucial role in the biosynthesis of characteristic aroma compounds in fruit. Despite the progress in understanding the LOX pathway in model plants like tomato, the distinct roles of individual members within the LOX gene family in flavor formation in the complex octoploid strawberry are still not fully understood. In this study, we identified 13 LOX genes in the strawberry genome and focused on a specific lipoxygenase gene, designated FaLOX11, which exhibited the highest expression during fruit ripening. Spatiotemporal expression analysis revealed that FaLOX11 expression was significantly correlated with 3-hexenal accumulation, quantified via headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS). Functional characterization via transient overexpression of FaLOX11 in strawberry fruits resulted in a significant increase in C6 volatile content, specifically a ~72% increase in 3-hexenal content. Conversely, RNA interference (RNAi)-mediated transient silencing of FaLOX11 significantly downregulated the expression of this gene and led to a marked reduction in the production of these key aroma compounds. Our findings demonstrate that FaLOX11 acts as a positive regulator of C6 aldehyde and alcohol biosynthesis, thereby playing a pivotal role in determining the characteristic aroma profile of strawberry fruit. This study provides new insights into the LOX pathway in strawberry and lays a solid molecular foundation for improving strawberry flavor quality. Full article

Quince (Cydonia oblonga Mill.) is an important fruit crop, yet a systematic quality evaluation framework is lacking. This study comprehensively characterized multiple germplasms from distinct production areas. An integrated strategy combining physicochemical analysis, FT-MIR (Fourier transform mid-infrared spectroscopy), electronic nose (E-nose), headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS), and chemometrics was employed. Significant variations were observed among accessions: certain varieties were observed to exhibit the highest pectin (1.86%) and total phenolic content (143.40 mg/100 g), while others showed superior firmness and titratable acidity. β-Damascenone in one accession was found to have an exceptionally high odor activity value (OAV) of 265.05. Multivariate analysis, including PLS-DA and OPLS-DA, effectively discriminated among quince accessions, with PLS-DA achieving 100% classification accuracy, and tentatively identified 18 key markers (VIP > 1) for accession discrimination. Loading scatter plot analysis further validated the contribution of these markers to the separation between accessions. However, due to the limited sample size (n = 18) and partial confounding between cultivar and origin, these findings should be considered exploratory and require validation in larger independent studies. This work provides preliminary insights into the diversity and geographical patterns of quality and flavor traits in quince germplasm, offering a preliminary foundation for germplasm evaluation and targeted utilization. Full article