Search Results (227)

Different heat treatment temperatures (85–115 °C) were evaluated for their effects on the quality and flavor of luncheon meat. As the heating temperature increased, the weight loss rate increased, and its color became darker. Low-field nuclear magnetic resonance (LF-NMR) revealed that immobilized water decreased progressively while bound and free water both increased. During heat treatment, alterations in the spatial structure of proteins reduced the hardness and chewiness of luncheon meat, accompanied by significant variations in amino acid contents. The MDA content increased from 0.34 to 0.69 mg/kg with increasing temperature, confirming enhanced lipid oxidation. Through gas chromatography–ion mobility spectrometry (GC-IMS) analysis, a total of 38 volatile organic compounds (VOCs) were identified, primarily aldehydes, ketones, and esters; the total aldehydes content increased by 57.5% from 85 °C to 115 °C. Combining odor activity values (OAV > 1) with orthogonal partial least squares-discriminant analysis (OPLS-DA, VIP > 1), 9 core flavor compounds were identified. Heating at 95 °C balanced aldehyde–ester flavor development with minimal quality loss. This study provides key theoretical foundations for optimizing heat treatment parameters in the industrial production of luncheon meat. Full article

Ethyl carbamate (EC) is a widely recognized carcinogen present in fermented foods, and enzymatic degradation is a safe and effective strategy for its reduction. An EC-degrading esterase derived from Acinetobacter calcoaceticus (AcECH) was previously identified. However, volatile ester compounds in Chinese Baijiu compete with EC for enzyme binding, thereby affecting degradation efficiency and flavor quality. In this study, molecular docking, molecular dynamics (MD) simulations, enzyme kinetics, bio-layer interferometry (BLI), and gas chromatography–ion mobility spectrometry (GC-IMS) were employed to investigate the substrate specificity of AcECH. Based on computational prediction and experimental validation, F157G has been identified as the most suitable mutant for improving substrate recognition. Compared with the wild-type enzyme, the degradation rates of ethyl acetate, ethyl valerate, and ethyl hexanoate decreased to 64.23%, 49.28%, and 34.08%, respectively. Meanwhile, F157G showed enhanced apparent binding affinity toward EC while largely maintaining EC hydrolytic activity, and reduced the degradation of desirable volatile esters, indicating an altered substrate preference of AcECH. 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

Headspace–gas chromatography–ion mobility spectrometry (HS-GC-IMS) combined with chemometrics was employed to track volatile aroma compounds during the nine-steaming and nine-drying process. A total of 84 volatile signals (including monomers, dimers, and polymers) were tentatively identified, of which 73 volatile compounds were semi-quantified. Principal component analysis (PCA) revealed a mixed clustering pattern across cycles, indicating that unsupervised methods alone could not adequately resolve the volatile changes. A partial least squares discriminant analysis (PLS-DA) model supported clear chemical discrimination among the three hypothesized stages—early (cycles 1–3), middle (4–6), and late (7–9). Based on VIP > 1 and ANOVA (q < 0.05), 29 key differential compounds were screened and categorized into three dynamic groups (decreasing, transient, and accumulating), revealing three proposed transformation windows: green-grassy odor dissipation (cycles 1–3), roasted/malty aroma generation (cycles 4–6), and aroma stabilization via end-product accumulation (cycles 7–9). Relative odor activity value (ROAV) analysis revealed a decoupling between abundance and sensory impact: high-abundance Maillard products like maltol showed negligible ROAV (<0.0003), whereas esters and aldehydes dominated the ROAV profiles, suggesting their potential as important contributors to the fruity, sweet, and malty notes. The maltol/α-cedrol ratio (M/C) increased by an order of magnitude after the seventh steaming, and color parameters E*ab correlated negatively with ester accumulation. This study provides chemical insights and quantitative indicators for aroma quality control and process determination in black ginseng production. Full article

To explore coffee’s effect on sweet rice wine quality, this study developed a novel fermented beverage using round glutinous rice and coffee powder as raw materials. The fermentation process was optimized using an orthogonal array design combined with fuzzy comprehensive evaluation. Flavor, physicochemical properties, and antioxidant activities were systematically evaluated via electronic tongue (E-tongue), gas chromatography–mass spectrometry (GC-MS), and gas chromatography–ion mobility spectrometry (GC-IMS). The optimal fermentation parameters were 0.6% fermentation starter (Jiuqu), 10% coffee powder, a fermentation time of 56 h, and a temperature of 28 °C. Adding coffee powder significantly increased total flavonoid content. Compared to the control group, the scavenging activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺), as well as hydroxyl radicals, increased by 18.36%, 7.40%, and 10.96%, respectively, compared to the control group. Flavor analysis identified 173 volatile organic compounds, demonstrating strong complementarity between GC-MS and GC-IMS. The addition of coffee powder preserved traditional sweet rice wine components while introducing roasted heterocyclic compounds, such as 2-methylpyrazine and 2-ethylfuran, thereby imparting nutty and roasted characteristics. E-tongue analysis revealed enhanced sensor responses for sweetness, bitterness, and saltiness, along with decreased umami. In conclusion, the addition of coffee powder is an effective strategy to enhance the in vitro antioxidant activity and enrich the flavor profile of sweet rice wine. This study provides a scientific basis for the application of coffee in traditional fermented foods. Full article

As a National Geographical Indication (GI) product, Wenzhou Ougan (WZ) is difficult to distinguish visually from mandarins of other origins. In this study, 34 peel samples and 47 juice samples from WZ and three external origins were analyzed by headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS), and their VOC fingerprints were compared. A total of 59 and 68 VOC signal variables were extracted from peel and juice samples, respectively; compound assignments were tentative annotations based on retention index and drift time matching with the GC-IMS library. Gallery plots and two-dimensional spectra revealed distinct differences in several VOC signal regions among origins. Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and variable importance in projection (VIP) values were used to evaluate grouping trends and screen discriminant VOC signal variables. For WZ-origin samples, the main WZ-high discriminant VOC signal variables in peel included furfuryl alcohol, 3-octanone, pentanal, n-nonanal, ethyl 2-methylbutyrate, butyl hexanoate, alpha-pinene, and 3-methylbutyric acid, while those in juice mainly included beta-ocimene, limonene, furfuryl alcohol, 2-acetylfuran, 2-methylfuran, butyric acid, and pentanoic acid. These findings indicate that integrated VOC fingerprints show potential for rapid geographical discrimination of Wenzhou Ougan, while further independent validation and complementary chemical confirmation are required. Full article

The flavor characteristics of three commercially important, cultivated mussel species (Mytilus coruscus, Mytilus galloprovincialis, and Perna viridis) were investigated through analyses of free amino acids, organic acids, 5′-nucleotides, fatty acids, and volatile organic compounds (VOCs). Distinct differences among species–sex groups were observed in both volatile and non-volatile flavor compounds. M. coruscus and M. galloprovincialis showed greater umami potential than P. viridis. Female M. galloprovincialis exhibited the highest equivalent umami concentration (EUC) (2.56 ± 0.21 g MSG/100 g), whereas male M. galloprovincialis and male M. coruscus contained the highest levels of sweet-tasting amino acids (605.42 ± 28.72 mg/100 g) and umami-tasting amino acids (209.29 ± 13.31 mg/100 g), respectively. Gas chromatography–ion mobility spectrometry (GC-IMS) analysis identified 67 volatile compounds, and 12 key discriminative volatiles were selected, including three aldehydes, four ketones, three alcohols, 2-ethylfuran, and acetic acid. Males generally showed higher omega-3 polyunsaturated fatty acids (ω-3 PUFAs)and omega-6 polyunsaturated fatty acids (ω-6 PUFAs) proportions than females, with the highest ω-3 PUFAs proportion in male M. coruscus (45.12 ± 0.22%) and the highest ω-6 PUFAs proportion in male P. viridis (8.13 ± 0.30%). Correlation analysis suggested that ω-6 PUFAs were more closely associated with aldehydes, whereas ω-3 PUFAs were more closely associated with alcohols and ketones. These associations provide preliminary evidence for understanding flavor differences among cultivated mussel groups. Full article

Roasting time strongly influences almond oil yield, flavor and oxidative stability. This study investigated almond oils obtained by pressing almond kernels roasted at 130 °C for 0, 5, 10 and 20 min, corresponding to cold-aroma, light-aroma, strong-aroma and sauce-aroma groups, respectively, by combining physicochemical analysis, fatty acid quantification, gas chromatography–ion mobility spectrometry (GC-IMS), machine learning and lipidomics. Increasing roasting time enhanced oil yield from 45.81% to 50.34%, with no further significant increase after 10 min. Stronger roasting moderately reduced the free radical level. In contrast, acid value, peroxide value and thiobarbituric acid reactive substances (TBARS) increased from 0.28 to 0.38 mg KOH/g oil, 1.20 to 1.46 meq O₂/kg oil and 0.38 to 0.46 mg malondialdehyde/kg oil, respectively, indicating limited oxidative deterioration. Fatty acid analysis showed that oleic acid remained relatively stable at 644.37–647.03 mg/g oil, whereas linoleic acid decreased significantly from 150.42 to 140.19 mg/g oil. GC-IMS detected 59 volatile signals and clearly separated the four processing groups, indicating substantial roasting-induced changes in volatile fingerprints. A positive–unlabeled (PU) learning model used 27 literature-supported aroma-active compounds as the positive class and 32 compounds without confirmed aroma-activity evidence as the unlabeled class. The model showed good cross-validated discrimination, with a mean area under the receiver operating characteristic curve (ROC-AUC) of 0.866 and a mean area under the precision–recall curve (PR-AUC) of 0.756, and prioritized eight unlabeled compounds, mainly alcohols and methional, as candidate aroma-active compounds requiring further sensory validation. Lipidomic analysis showed that accelerated oxidation caused broad lipid remodeling, with 327 differential lipids between cold-aroma oxidized and unoxidized oils, mainly involving glycerophospholipids, glycerol lipids, sphingolipids and fatty acyls. Overall, increasing roasting time improved oil recovery and promoted aroma differentiation while causing only limited initial oxidative deterioration, providing a theoretical basis for optimizing roasting conditions in industrial processing. 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

Atractylodis Rhizoma is an important traditional Chinese medicinal material derived from two botanical origins, Maocangzhu (MCZ) and Beicangzhu (BCZ), which are difficult to distinguish by conventional morphological identification because of their similar appearance. However, differences in botanical origin may lead to variations in odor, taste, volatile constituents, and non-volatile metabolites, thereby affecting quality evaluation and clinical application. This study aimed to systematically characterize the sensory and chemical differences between MCZ and BCZ and to identify potential markers for their discrimination. A multi-dimensional analytical strategy combining electronic nose, electronic tongue, headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS), and ultra-high-performance liquid chromatography–Orbitrap high-resolution mass spectrometry (UPLC-Orbitrap MS) was established. Electronic nose and electronic tongue were used to digitize odor and taste characteristics, HS-GC-IMS was employed to profile volatile organic compounds, and UPLC-Orbitrap MS was applied to characterize non-volatile metabolites. Principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), variable importance in projection (VIP) screening, permutation tests, and correlation analysis were further used to evaluate discrimination performance and screen characteristic markers. The electronic nose results showed that MCZ and BCZ exhibited distinct odor profiles, with W5S, W1W, and W1S identified as the main differential sensors, suggesting that nitrogen oxides, terpenoids, inorganic sulfides, and short-chain alkanes contributed to the odor differences between the two origins. Electronic tongue analysis further demonstrated clear taste discrimination, with sourness and richness identified as the key taste indicators. HS-GC-IMS detected 108 volatile organic compounds, and 24 volatile markers with VIP > 1.2 were screened as important contributors to the differentiation of MCZ and BCZ. Among them, propionic acid and 5-methyl-2-furancarboxaldehyde were mainly distributed in MCZ, whereas (E)-caryophyllene was present only or at higher levels in BCZ, indicating its potential as a characteristic volatile marker of BCZ. UPLC-Orbitrap MS detected 78 non-volatile constituents, and OPLS-DA screened 17 key non-volatile differential metabolites with VIP > 1.2. These results indicated that MCZ and BCZ could be clearly separated not only by sensory signals but also by volatile and non-volatile chemical profiles. This study revealed that the differences between MCZ and BCZ are mainly reflected in odor-active volatile compounds, key taste indicators, and non-volatile differential metabolites. The integration of electronic nose, electronic tongue, HS-GC-IMS, and UPLC-Orbitrap MS provides a comprehensive and reliable strategy for distinguishing the two botanical origins of Atractylodis Rhizoma. These findings provide valuable insights into the material basis underlying the sensory and chemical differences between MCZ and BCZ and offer scientific support for accurate authentication, quality evaluation, and rational clinical application of Atractylodis Rhizoma. Full article

The volatile compounds (VOCs) evolution of wild ginseng (WG) across growth years is not a unidirectional process but a divergent remodeling of the chemical fingerprint. In this study, HS-GC-IMS combined with chemometrics was employed to characterize the dynamic changes in VOCs in WG at four growth stages (10, 15, 20, and 25 years). Samples were collected from three independent sites, with ≥5 roots pooled per site per age group to obtain population-representative composite samples. A total of 68 VOCs were tentatively identified and semi-quantified. Terpenes and pyrazines exhibited the most pronounced directional trends: terpenes such as camphene, (E,E)-α-farnesene, and β-ionone accumulated progressively (increases of 242%, 74.6%, and 93.4%, respectively), whereas pyrazines showed an overall decline through distinct trajectories—2,3,5-trimethylpyrazine declined monotonically (57.3%), 2-ethyl-6-methylpyrazine decreased moderately (27.7%), and 2,5-dimethylpyrazine exhibited a transient peak at 20 years before a sharp terminal decline (52.3%). In contrast, the majority of compounds (66%) displayed non-monotonic patterns, underscoring the complexity of this divergent evolution. Partial least squares-discriminant analysis (PLS-DA) effectively distinguished samples across growth years (R²Y = 0.997, Q² = 0.993), with a 200-times permutation test confirming no overfitting. 29 differential compounds (VIP > 1) were identified. The divergent accumulation patterns of terpenes and pyrazines, together with 29 VIP-identified differential compounds, provide chemical evidence that the VOCs fingerprint could serve as a supplementary tool for growth-year assessment. These findings provide chemical evidence that WG flavor quality evolves divergently over time, suggesting that VOCs fingerprint could serve as a supplementary tool for growth-year assessment, particularly for “high-quality but poor-shape” specimens that are undervalued by traditional morphology-based methods. Full article

Pineapple glutinous rice wine is a popular fermented beverage, yet its flavor and quality remain highly affected by yeast strains. This study aimed to explore the effects of four commercial yeasts, namely La Raffinée (Ra), La Bayanus (Ba), La Délicieuse (De), and Angel wine yeast (AWY), on the quality of pineapple glutinous rice wine. Fermentation indices including Brix and alcohol content were dynamically monitored, while final wine samples were analyzed for color difference, sensory quality and aroma components by gas chromatography–ion mobility spectrometry (GC-IMS). Results showed that all yeasts had optimal fermentation efficiency, sugar-to-alcohol conversion, physicochemical properties and sensory quality at an addition level of 0.2 g/L. The 0.2 g/L De group achieved the optimal overall quality with an alcohol content of 10.01% vol, the highest ester content (22.55%) and the lowest acid content (12.18%), presenting a balanced flavor, prominent pineapple aroma and refreshing taste. In contrast, Ba led to higher acidity and Angel wine yeast contributed to greater sweetness. Overall, 0.2 g/L De yeast effectively coordinated pineapple aroma and glutinous rice wine characteristics, providing a practical reference for optimizing the production and quality improvement of pineapple glutinous rice wine. Full article