Molecular Sensory Science Research Articles

Correlation between autochthonous microbial communities and flavor profiles during the fermentation of mustard green paocai (Brassica juncea Coss.), a typical industrial-scaled salted fermented vegetable

Mustard green paocai is a salted vegetable product that is fermented with low salt in the initial stage and preserved with high salt in the middle stage. To reveal the key flavor-producing potential of core bacterial and fungal communities during the 365-day fermentation of industrial-scaled paocai. In this study, microbiome and molecular sensory science were used to analyze potential relationships between microbial diversity and key flavor compounds. The results showed that bacteria were more diverse than fungi. High salinity improved the flavor of industrial paocai and simplified the microbial community. A total of 74 bacterial and yeast strains were isolated and identified throughout the fermentation process. Lactiplantibacillus, Halanaerobium, Halomonas, Pseudomonas, and Enterobacteriaceae were the dominant bacterial genera, and Debaryomyces hansenii was the core fungal genera in paocai. 4-Ethylphenol, anethole, butanoic acid, 4-ethylguaiacol, and 3-methyl-1-butanol were identified as key flavor compounds in industrial paocai with odor activity values greater than 1. Spearman correlation analysis indicated that bacteria have a greater impact on the flavor of paocai than fungi. Halanaerobium and Halomonas were correlated with flavor and spoilage in paocai. This study provides guidance for the production of desirable flavors by multi-bacteria synergistic fermentation of industrial paocai.

Characterization of the key odorants of ripe Capparis spinosa L. fruit and changes in concentrations after storage by means of molecular sensory science

To characterize the key odorants in ripe Capparis spinosa L. fruit (RCF) and to investigate changes in the odorants after storage, volatiles were captured by both solid-phase microextraction and solvent extraction combined with solvent-assisted flavor evaporation; a total of 22 aroma-active regions were detected in the isolates by gas chromatography–olfactometry. Of 19 odor-active compounds identified positively, 13 odorants were found in RCF for the first time; their flavor dilution factors ranging from 1 to 512 were measured by an aroma extract dilution assay. Eleven odorants were determined as the key odorants by stable isotope dilution analysis, odor activity value (OAV) calculation, and recombination experiments. To further investigate the changes in odorants after storage, their concentrations and OAVs were determined. The results showed that the number of key odorants did not change before and after storage, but the concentrations of octanoic acid, sotolon, and 3-methylbutanoic acid increased markedly.

Unraveling the flavor profile and microbial roles during industrial Sichuan radish paocai fermentation by molecular sensory science and metatranscriptomics

In this study, the changes of flavor profile, the succession rules of active microorganisms and their correlation were analyzed during the fermentation process of industrial Sichuan radish paocai, in order to further explore the composition of ingredients that constitute the unique flavor characteristics of industrial Sichuan radish paocai, and the microorganisms and enzymes that may contribution to it. To this end, molecular sensory, high performance liquid chromatography and metatranscriptomics were employed to identify the aroma-active compounds, non-volatile compounds and active microorganisms during the 197-day fermentation process of industrial Sichuan radish paocai, respectively. Twenty aroma-active compounds were identified, of which 12 compounds had odor activity values ≥ 1, and some off-flavor compounds were significantly lower than those of fresh radish. After 100 days of fermentation, aroma-active compounds began to accumulate extensively with the dominant active microorganisms transforming from fungi to bacteria. Among the potential formation pathways of 14 aroma-active compounds, most of which were dominated by Lactobacillus and Debaryomyces, and were contributed by other microorganisms mainly belong to Lactobacillales, Saccharomycetales and Bacillales. This study provides new insights into the flavor formation and microbial metabolic roles of industrialized paocai, as well as valuable references for screening and isolation of functional strains, expression and characterization of flavor enzymes.

Analysis of key precursor peptides and flavor components of flaxseed derived Maillard reaction products based on iBAQ mass spectrometry and molecular sensory science

Flaxseed derived Maillard reaction products (MRPs) have typical meaty flavor, but there is no report on comparison of their amino acids and peptides reactivity. The peptides and amino acids of flaxseed protein hydrolysates were separately collected by G-15 gel chromatography. Taste dilution analysis (TDA) showed that peptides-MRPs had high umami, mouthfulness, and continuity enhancement. Further, LC-MS/MS revealed that flaxseed protein hydrolysates consumed 41 peptides after Maillard reaction. Particularly, DLSFIP (Asp-Leu-Ser-Phe-Ile-Pro) and ELPGSP (Glu-Leu-Pro-Gly-Ser-Pro) accounted for 42.22% and 20.41% of total consumption, respectively. Aroma extract dilution analysis (AEDA) indicated that formation of sulfur-containing flavors was dependent on cysteine, while peptides were more reactive than amino acids for nitrogen-containing heterocycles. On the other hand, 11 flavor compounds with flavor dilution (FD) ≥ 64 were identified for flaxseed derived MRPs, such as 2-methylthiophene, 2-methyl-3-furanthiol, furfural, 2-furfurylthiol, 3-thiophenethiol, thieno[3,2-b] thiophene, 2,5-thiophenedicarboxaldehyde, 2-methylthieno[2,3-b] thiophene, 1-(2-methyl-3-furylthio)-ethanethiol, 2-methylthieno[3,2-b] thiophene, and bis(2-methyl-3-furyl)-disulfide. In addition, we further demonstrated the flavors formation mechanism of flaxseed derived MRPs.

Characterisation of the volatile compounds profile of Chinese pan-fried green tea in comparison with baked green tea, steamed green tea, and sun-dried green tea using approaches of molecular sensory science

Pan-fried green tea (PGT) is an easily acceptable tea drink for general consumers. In this study, volatile profiles and characteristic aroma of 22 representative Chinese PGT samples were extracted using stir bar sorptive extraction (SBSE) and analysed by gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O) analysis, and odour activity value (OAV) calculations. In total, 88 volatile compounds were identified. Alcohols (45%), esters (19%), and ketones (16%) were the dominant volatiles, and geraniol (484.8 μg/kg) was the most abundant volatile component in PGT, followed by trans-β-ionone and linalool. In addition, the differences of aroma characteristics among PGT and other three types of green tea, namely baked green tea, steamed green tea, and sun-dried green tea, were also observed using partial least squares discriminant analysis (PLS-DA) and heatmap analysis, and it was found that β-myrcene, methyl salicylate, (E)-nerolidol, geraniol, methyl jasmonate were generally present at higher content in PGT. This is the first comprehensive report describing the volatile profiles of Chinese PGT, and the findings from this study can advance our understanding of PGT aroma quality, and provide important theoretical basis for processing and quality control of green tea products.

Comparative analysis of aroma compounds in French fries and palm oil at three crucial stages by GC/MS-olfactometry, odor activity values, and aroma recombination.

Flavor is a key element affecting the popularity of French fries (FFs). When oil is heated, the changes in oil quality can affect the flavor of the food directly. The flavor of FFs showed three crucial stages: the break-in (3.0% to 6.8% of total polar compounds (TPC)), optimum (7.0% to 19% of TPC), and degrading (above 19.5% of TPC) stages. To distinguish the key aroma compounds in the three stages, the FFs, prepared in palm oil (PO) at TPC of 3.0% (FF3), 7.5% (FF8), 19.5% (FF20), and their relevant oils (PO3, PO8, PO20), were selected for molecular sensory science analysis. The results indicated that the concentration of (E, E)-2,4-decadienal linked with the deep-fried odor was low in FF3, which led to a lower sensory score in the FF3 sample. The FF8 sample had a high (E, E)-2,4-decadienal content and received a high sensory score. The FF20 sample possessed high hexanoic acid, heptanoic acid (sweaty odor), benzaldehyde (stale odor), octanoic acid (sweaty odor), (E)-2-undecenal (fatty odor), and trans-4,5-epoxy-(E)-2-decenal (metallic odor) content, thus leading to FFs having an undesirable flavor and PO20 showed high hexanoic acid and heptanoic acid content, contributing to a lower sensory score in PO20. The FFs' flavor became undesirable when TPC was above 19.5% due to significant influences of some off-flavor compounds. It is therefore essential to prevent the generation of rancid substances to prolong the optimum stage during frying. © 2021 Society of Chemical Industry.

Characterization of aroma profiles and aroma-active compounds in high-salt and low-salt shrimp paste by molecular sensory science

Flavor characteristics of raw shrimp, high-salt and low-salt shrimp paste were evaluated and compared by sensory analysis, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). In addition, aroma profiles and aroma-active compounds in these three samples were analyzed by solvent-assisted flavor evaporation-gas chromatography-olfactometry-mass spectrometry (SAFE-GC-O-MS). Results of sensory evaluation revealed that these three samples showed significant differences in sensitivity to the W2W, W2S, W1S and W1W sensors of the electronic nose (p < 0.05), which represent organic sulfides, alkane aromatic compounds, short chain alkanes, and sulfides, respectively. Assessment of sensory parameters indicated tha high-salt shrimp paste had a strong roasted and meaty aroma, while low-salt shrimp paste showed an umami aroma more similar to raw shrimp. A total of 118 volatile compounds were identified using the three afore-mentioned gas chromatography methods. Among them, 37 aroma-active compounds were detected by GC-O. High-salt shrimp was shown to contain more acids, aldehydes and heterocyclic compounds, which resembled cheese, roasted and meaty aromas. In contrast, low-salt shrimp paste contained more esters, which was similar to the umami aroma profile of raw shrimp. Interestingly, pyrazines were only produced in fermented shrimp paste samples, suggesting that they were produced during the fermentation process and they may contribute unique roasted and meaty aromas, which were important for the overall aroma characteristics of shrimp paste.

Investigations on the Key Odorants Contributing to the Aroma of Children Soy Sauce by Molecular Sensory Science Approaches.

To investigate the key odor-active compounds in children’s soy sauce (CSS), volatile components were extracted by means of solvent extraction coupled with solvent-assisted flavor evaporation (SE-SAFE) and solid-phase microextraction (SPME). Using gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS), we identified a total of 55 odor-active compounds in six CSSs by comparing the odor characteristics, MS data, and retention indices with those of authentic compounds. Applying aroma extract dilution analysis (AEDA), we measured flavor dilution (FD) factors in SE-SAFE isolates, ranging from 1 to 4096, and in SPME isolates, ranging from 1 to 800. Twenty-eight odorants with higher FD factors and GC-MS responses were quantitated using the internal standard curve method. According to their quantitated results and thresholds in water, their odor activity values (OAVs) were calculated. On the basis of the OAV results, 27 odorants with OAVs ≥ 1 were determined as key odorants in six CSSs. These had previously been reported as key odorants in general soy sauce (GSS), so it was concluded that the key odorants in CSS are the same as those in GSS.

Characterization of the major aroma-active compounds in peach (Prunus persica L. Batsch) by gas chromatography–olfactometry, flame photometric detection and molecular sensory science approaches

Aroma profiles and aroma-active compounds of “Yulu” peach from Fenghua (the peach known for the best flavor and quality in China) were investigated by headspace solid-phase microextraction (HS-SPME), solvent-assisted flavor evaporation (SAFE), gas chromatography–olfactometry (GC–O), gas chromatography–mass spectrometry (GC–MS), and flame photometric detection (FPD). The combination of these methods improved the analysis and identification of aroma substances compared to the combination of a single aroma extraction method and GC–MS. A total of 85 aroma-active compounds, including 10 sulfur compounds were detected. Methional, methyl 3-(methylthio)propionate, methionol, and benzothiazole were first detected in peaches. These aroma compounds cannot only supplement the database of aroma substances of peaches, but also provide data support for traceability of the origins of “Yulu” peaches. In addition, the odor activity value (OAV) was used to identify the contributions of the most important compounds. The results indicated that hexanal, 3-methylbutanal, (E)-2-hexen-1-ol, 3-mercaptohexyl acetate, (E,E)-2,4-decadienal, 2-methylpropanal, γ-decalactone, 2-methylbutanal, theaspirane, and δ-decalactone were the key aroma-active compounds. The key characteristic aroma components were further ascertained by aroma reconstitution and omission experiments, which showed that the fruity, floral, sulfur, and sour notes could be well simulated. Finally, the perceptual interactions between different sulfur compounds and fruity recombination (FR) were explored. 3-mercaptohexanol and 4-methyl-4-mercaptopentan-2-one could significantly decrease the threshold of FR. The possible reason was that these two sulfur compounds had synergistic effects with the aroma compounds in FR, with the U model confirming the results of these synergistic effects. The perceptual interactions provide a basis for the regulation of characteristic fruity aroma of peach products.

Characterization of key aroma compounds in pixian broad bean paste through the molecular sensory science technique

The Pixian broad bean paste (PBBP) is widely welcomed by consumers in China due to its unique aroma. The objective of this study was to characterize the key aroma of PBBP. The aromas of PBBP were fractionated by normal phase-liquid chromatography (NP–LC) and detected and identified by gas chromatography-olfactory (GC–O) coupled with gas chromatography-mass spectrometry (GC–MS), and quantitated by stir bar sorptive extraction (SBSE). The results showed that 58 aroma-active compounds were identified in PBBP, of which acids and phenolics had the highest concentration, and 39 odorants were demonstrated as important odorants. Besides, aroma recombination tests and statistical analysis showed that the original PBBP and recombinant have no significant difference in sweat/sour, roasted, and floral attributes, proving that this study successfully simulated the typical aroma of PBBP. The omission tests demonstrated 4-ethylguaiacol and 4-vinylguaiacol as the key odorants and revealed the significance of sotolon, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), the entire class of phenolics, and the entire class of acids, particularly acetic acid, 3-methylbutanoic acid, 4-methylpentanoic acid may have a synergistic effect, for the overall aroma of the PBBP.

An Insight by Molecular Sensory Science Approaches to Contributions and Variations of the Key Odorants in Shiitake Mushrooms

An insight using molecular sensory science approaches to the contributions and variations of the key odorants in shiitake mushrooms is revealed in this study. Odorants were extracted by headspace solid phase microextraction (HS-SPME) and direct solvent extraction combined with solvent-assisted flavor evaporation (DSE-SAFE) in fresh and hot-air-dried shiitake mushrooms. Among them, 18 and 22 predominant odorants were determined by detection frequency analysis (DFA) and aroma extract dilution analysis (AEDA) combined with gas chromatography-olfactometry (GC-O) in the fresh and dried samples, respectively. The contributions of these predominant odorants in the food matrix were determined by quantification and odor activity values (OAVs) with aroma recombination verification. There were 13 and 14 odorants identified as key contributing odorants to overall aroma, respectively. 1-Octen-3-ol and 1-octen-3-one were the most key contributing odorants in the fresh samples in contributing mushroom-like odor. After hot-air-drying, the OAV and concentrations on dry basis of the key contributing odorants changed, due to oxidation, degradation, caramelization and Maillard reactions of fatty acids, polysaccharides and amino acids. 1-Octen-3-ol was reduced most significantly and degraded to 1-hydroxy-3-octanone, while phenylethyl alcohol increased the most and was formed by phenylalanine. In hot-air-dried samples, lenthionine became the most important contributor and samples were characterized by a sulfury odor. Overall contributions and variations of odorants to the aroma of shiitake mushrooms were revealed at the molecular level.

Characterization of the key aroma compounds in Chinese JingJiu by quantitative measurements, aroma recombination, and omission experiment

The unique flavor of and rich physiological activities exhibited by the Chinese JingJiu has made it become an essential part of the blended alcoholic beverage. In this study, the aromatic characteristics of Chinese JingJiu have been identified using sensory analysis, aroma extraction dilution analysis (AEDA), and quantitative analysis techniques. The odor activity values (OAVs) were also used to characterize the compound. A total of 136 aroma compounds were identified through the AEDA and gas chromatography-mass spectrometry (GC–MS) techniques. The flavor dilution (FD) factors were found to be in the range of 2–1024. Seventy aroma-active compounds with FD ≥ 8 were identified. Forty-three aroma-active compounds were identified using the molecular sensory science approach. Furthermore, 13 compounds were confirmed to be the key aroma-active compounds present in the Chinese JingJiu. The work provides a certain guiding effect on the regulation and optimization of the Chinese JingJiu production process.

Characterizing volatile metabolites in raw Pu’er tea stored in wet-hot or dry-cold environments by performing metabolomic analysis and using the molecular sensory science approach

The aroma profile of raw pu’er tea (RPT) depends on its storage duration (2–10 years) and storage conditions (wet-hot or dry-cold environment). We analyzed the major odorants of RPT samples by performing metabolomic analysis and by using the molecular sensory science approach. Under dry-cold storage conditions, tea leaves had more carotenoid derivatives, glycoside-derived volatiles, and phenolic volatiles, resulting in “fresh,” “floral,” and “sweet” aroma. Under wet-hot storage conditions, tea leaves had more methoxybenzenes, which contributed considerably to their “stale” and “woody” aroma. We identified 11 and 4 compounds as the odor markers of RPTs when stored in dry-cold and wet-hot environments, respectively. Our findings provide a scientific basis for optimal storage that yields the desired aroma profile.

Effects of electron-beam irradiation on volatile flavor compounds of salmon fillets by the molecular sensory science technique.

Vacuum-packed salmon was treated by electron beam irradiation preservation technology, to study the effects of electron-beam irradiation on odor active compounds of salmon by two types of methods for extraction: headspace-solid phase micro extraction (HS-SPME) and solvent assisted flavor evaporation (SAFE). Volatile flavor compounds examined by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O), combined with aroma extract dilution method (AEDA) and odor activity value (OAV) for identification of important odorants. In addition, the correlation between sensory attributes and volatile compounds of salmon irradiated at different doses was analyzed by partial least squares regression (PLSR). The results showed that after SPME and SAFE extraction, a total of 49 and 70 volatile flavor compounds were detected in salmon before and after electron beam irradiation. AEDA and OAV were further identified, among which 10 odorants were considered as important volatile flavor compounds and played an important role in the formation of aroma contours such as meaty, fatty, and grassy in salmon. In addition, methanethiol, 3-methyl butyraldehyde, 3-methyl propyl aldehyde, dimethyl disulfide, dimethyl trisulfide, and 2-pentyl furan were identified as the important volatile flavor compounds in salmon irradiated with 4 kGy, and were also the unique compounds that constituted irradiation off-odor. In general, salmon irradiated with 1 kGy showed the best aroma profile. PRACTICAL APPLICATION: SPME and SAFE were used as two types of extraction methods for volatile compounds of salmon, which complemented each other. Additionally, combined with AEDA and OAV, characteristic flavor compounds were identified. Furthermore, the odor fingerprint of salmon with E-beam irradiation was established for the first time.

Insights into the major aroma-active compounds in clear red raspberry juice (Rubus idaeus L. cv. Heritage) by molecular sensory science approaches

The major aroma-active compounds in clear red raspberry juice were identified by molecular sensory science approaches. Thirty-one aroma-active compounds were identified using detection frequency analysis and aroma extract dilution analysis. Among them, 18 volatiles with aroma activity in red raspberry were identified for the first time, while 14 volatiles with odor activity values (OAVs) ≥ 1 were confirmed as the major aroma-active compounds. Three C6 aldehydes showed the highest detection frequencies of 8, and β-ionone exhibited the highest OAV of 9507 and flavor dilution factor of 512, which indicated that the floral and grassy note could be dominant in overall aroma. Quantitative descriptive analysis suggested that the grassy, floral, woody, and caramel-like notes can be simulated using aroma recombination model 1. Electronic nose analysis also demonstrated that model 1 had closer similarity to the original juice than others. The combination strategy used here would help improve the knowledge of red raspberry aroma.

Characterization of key aroma compounds in traditional Chinese soy sauce through the molecular sensory science technique

Sensory evaluation revealed that traditional high-salt liquid-state soy sauce (THLS), a popular seasoning in China, has a caramel-like/sweet, roasted, nutty, cooked potato-like, and spicy/burnt aroma. As a comparative sample, commercial high-salt liquid-state soy sauce (CHLS) showed a similar aroma profile; however, the aroma intensity was stronger and richer in THLS. Gas chromatography−olfactometry−mass spectrometry and aroma extract dilution analysis of the aroma concentrates, prepared by solvent-assisted flavor evaporation, revealed the presence of over 70 odor-active compounds. Among them, methional had the highest flavor dilution factor. Maltol, 4-ethylguaiacol, and phenylacetaldehyde were detected with a higher flavor dilution factor in THLS than in CHLS. Quantitative analysis indicated that the concentrations of 11 key aroma compounds were higher in THLS than in CHLS. The sensory evaluation suggested that the aroma profile of the aroma recombination sample was similar to that of THLS. HEMF, 2-acetyl-1-pyrroline, methional, HDMF, 4-ethylguaiacol, phenylacetaldehyde, 2,3-diethylpyrazine, 2-phenylethanol, furfuryl alcohol, 2,3-butanediol, and maltol imparted the overall aroma profile to THLS.

Characterization of key aroma compounds in Laobaigan Chinese Baijiu by GC×GC‐TOF/MS and means of molecular sensory science

AbstractLaobaigan (LBG) Baijiu is recognized as one of the famous Chinese liquors due to its unique flavor characteristics. However, its key aroma‐active volatiles are still unknown. In this study, 414 volatile chemicals in the LBG Baijiu were initially detected by comprehensive two‐dimensional gas chromatography‐time‐of‐flight mass spectrometry (GC×GC‐TOF/MS). Then, 52 of them were determined by sample dilution analysis (SDA) for screen of aroma‐active compounds. Based on their odor–activity values (OAVs) that were determined by the external standard method performed on the GC×GC‐TOF/MS, 32 volatile compounds were further recognized as important odorants, which were reconstituted to simulate and validate the aroma profile of the LBG Baijiu. Moreover, omission experiments were conducted to corroborate the importance of key odorants. As a result, nine aroma compounds were finally confirmed as the key aroma‐active compounds of the LBG Baijiu.

Identification of the cooked off-flavor in heat-sterilized lychee (Litchi chinensis Sonn.) juice by means of molecular sensory science

The main contributors to the cooked off-flavor in heat-sterilized lychee juice (HLJ) were studied by means of molecular sensory science. The HLJ which elicited cooked cabbage/potato and onion/garlic off-flavor was compared with fresh lychee juice (FLJ) having desired sensory attributes via chemical analysis and sensory evaluation. Aroma extract dilution analysis, quantitative analysis and calculation of odor activity values (OAVs) were conducted on both FLJ and HLJ. The results showed that compared with FLJ, 15 compounds had increased OAVs in HLJ, among which, dimethyl sulfide (DMS), methional, dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and 2,4-dithiapentane presented cooked cabbage/potato, garlic/onion and sulfurous impression. The omission experiment proved that DMS, methional, DMTS, DMDS, 3-methylbutanal and 2,4-dithiapentane had significantly negative effects on the overall aroma of HLJ. Further studies on HLJs from other varieties of lychee confirmed that DMS, methional, DMTS, DMDS and 3-methylbutanal were responsible for the cooked off-flavor of HLJ in general.

Characterization of the Key Aroma Compounds in Two Differently Dried Toona sinensis (A. Juss.) Roem. by Means of the Molecular Sensory Science Concept.

A systematic approach for the characterization of the key aroma-active compounds in sun-dried Toona sinensis (SDTS) and vacuum-dried T. sinensis (VDTS) was performed by means of the molecular sensory science concept. A total of 64 aroma-active compounds were identified via gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). Aroma extract dilution analysis (AEDA) and static headspace dilution analysis revealed 39 odorants in SDTS and 32 odorants in VDTS with flavor dilution (FD) factors from 8 to 4096, with the highest for vanillin and eugenol in both samples. Stable isotope dilution analysis (SIDA) and an internal standard method were applied to quantitate 42 odorants, revealing 35 compounds in concentrations above their respective odor thresholds in SDTS and 29 compounds in VDTS, respectively. Calculation of odor activity values (OAVs) indicated 2-isopropyl-3-methoxypyrazine, eugenol, and β-ionone with the highest OAVs in both samples. Recombination experiments of the overall aromas of SDTS and VDTS by mixing the odorants with OAVs ≥1 in their naturally occurring concentrations proved the successful identification and quantitation of the respective key odorants.

Characterization of key aroma compounds in Chinese Guojing sesame-flavor Baijiu by means of molecular sensory science

Key odorants of Guojing sesame-flavor Baijiu were identified using the concept of molecular sensory science, including aroma extract dilution analysis (AEDA) based on gas chromatography–olfactometry (GC–O) combined with gas chromatography-mass spectrometry (GC–MS). A total of 509 volatile compounds were detected by comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC–TOF–MS). Sixty-one aroma-active compounds were identified via AEDA. Among them, two compounds with strong roasted aroma showed the highest flavor dilution (FD) factors of 19,683 and 6561. By using pure standards, aroma tests, and GC–MS, the compound with FD = 19683 was identified as benzenemethanethiol, which is reported for the first time in Baijiu. Sixty compounds were quantified by means of internal standard curve method, and 39 of them had odor activity values (OAVs) ≥ 1. Ethyl hexanoate, ethyl octanoate, and dimethyl trisulfide showed the highest OAVs, indicating that they contribute significantly to the aroma of Guojing sesame-flavor Baijiu.