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Frankincense is an important seasoning and spice known for its distinctive and intricate flavor profile. Considering the considerable variation in the aromatic quality of frankincense due to geographical origin, species diversity and cultivation conditions, frankincense from major global origins was characterized holistically for the first time. The electronic nose (E-nose) with headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and sensory evaluation were implemented to characterize the aroma components of 21 commercial varieties of frankincense from around the world. The results showed that a total of 149 volatile organic compounds (VOCs) of 10 categories were identified in frankincense, among which the numbers of alcohols, terpenes and esters compounds accounted for 22.15 %, 18.79 % and 15.44 % of the total VOCs of frankincense, respectively. The PLS-DA model effectively distinguished frankincense from Oman/Somalia and other origins. Furthermore, the study identified two differential VOCs with VIP > 1 in three Asian countries and five in six African countries. The total VOCs content and sensory characteristic score of "Lemon/Citrus" in Oman frankincense is significantly higher than other regions. The OAV results showed that 61 substances (e.g., Diacety, alpha-Pinene, Camphene, Myrcene) as key aroma compounds and OICS model indicated that p-Cymenol was found to contribute significantly to the citrus aroma in frankincense. This study identified the fundamental components of frankincense flavor and revealed different flavor descriptors of frankincense, which are crucial for reconstructing frankincense flavor and improving flavor quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Aroma has an important influence on the aroma quality of chicken meat. This study aimed to identify the characteristic aroma substances in chicken meat and elucidate their metabolic mechanisms. Using gas chromatography-olfactometry and odor activity values, we identified nonanal, octanal, and dimethyl tetrasulfide as the basic characteristic aroma compounds in chicken meat, present in several breeds. Hexanal, 1-octen-3-ol, (E)-2-nonenal, heptanal, and (E,E)-2,4-decadienal were breed-specific aroma compounds found in native Chinese chickens but not in the meat of white-feathered broilers. Metabolomics analysis showed that L-glutamine was an important metabolic marker of nonanal, hexanal, heptanal, octanal, and 1-octen-3-ol. Exogenous supplementation experiments found that L-glutamine increased the content of D-glucosamine-6-P and induced the degradation of L-proline, L-arginine, and L-lysine to enhance the Maillard reaction and promote the formation of nonanal, hexanal, heptanal, octanal, and 1-octen-3-ol, thus improving the aroma profile of chicken meat., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The ripe Gannan navel oranges have an appealing aroma, but few studies have reported the changes of these aromatic substances during the growth of navel oranges. In this study, changes of aroma components in Gannan navel orange from 119 to 245 days after flowering were systematically studied using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) coupled with multivariate analysis, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). A total of 43 and 54 aroma components were identified in pulp and peel of navel orange, respectively. The odor active value (OAV) results indicated that 14 substances were the key aroma components during the growth of navel orange. Among them, the contribution of linalool, β-myrcene and limonene were the highest. The multivariate statistical analysis further confirmed that 14 and 18 compounds could be used as key markers to distinguish the pulp and peel at different growth stages, respectively. Results from this study contributed to a better understanding of the dynamic variation and retention of aroma compounds during navel orange growth, and have great potential for industrial application., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Aroma is one of the significant quality factors of dark tea (DT). However, for a single large-leaf tea variety, there are few studies analyzing the effect of pile-fermentation on the aroma quality of DT. The GC × GC-QTOFMS, electronic nose (E-nose) and GC-olfactometry (GC-O) techniques were employed to analysis the difference of tea products before and after pile-fermentation. A total of 149 volatile metabolites (VMs) were identified, with 92 VMs exhibiting differential characteristics. Among these, 31 VMs with OAV > 1.0 were found to be correlated with E-nose results (|r| > 0.8). Additionally, GC-O analysis validated seven major differential metabolites. Notably, naphthalene, 2-methylnaphthalene, and dibenzofuran were found to enhance the woody aroma, while (Z)-4-heptenal, 2-nonenal and 1-hexanol were associated with an increase in mushroom, fatty and sweet odors, respectively. Moreover, 1-octen-3-ol was linked to reducing pungent fishy smell. These findings could provide a certain theoretical basis for understanding the influence of pile-fermentation on the aroma quality of dark tea., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Early reviews focused on volatile compounds in cooked meat or meat products by GC-MS analysis. However, actually only a small number of odor-active activities, i.e., odorants, play roles in meat aroma. This review summarized in total 332 odorants identified in thermally cooked meat species (e.g., stewed pork) in the recent 40 years by GC-O through the search of relevant literatures. They included l57 compounds from the lipid degradation, 98 compounds from the Maillard reaction, 18 compounds from the interaction of the lipid degradation and the Maillard reaction (lipid-Maillard interaction), and 59 compounds from other sources, while the formation mechanisms are discussed based on the recent developments. Overall, the aliphatic aldehydes had the greatest number, followed by sulfur-containing compounds, nitrogen-containing heterocyclic compounds, oxygen-containing heterocyclic compounds, ketones, alcohols, etc. The frequently potent odorants in different cooked meat species are the short-chain aliphatic aldehydes of C 6 -C 10 carbons and 1-oceten-3-ol (or 1-octen-3-one) and sulfur-containing or nitrogen-containing heterocyclic compounds. PLS-DA analysis suggested variation of odorants among the cooked beef, pork, poultry, and sheep was more due to the lipid degradation than the Maillard reaction, and marginally due to the lipid-Maillard interaction. This review can be used as guidance in improving flavor of cooked meat and meat flavorings., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A number of lactones and furanones associated with pleasant odorants play a vital role in grape and wine aroma profiles. However, they are usually present at trace levels and are particularly challenging to measure. In this work, an optimized method based on solid-phase extraction (SPE) coupled with gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS/MS) was developed for simultaneous determination of 14 lactones and 3 furanones. The validation was carried out using different types of wine as matrices, and satisfactory linearity, sensitivity, trueness and precision were confirmed. Furaneol and sotolon showed significantly lower limits of detection (LODs) in three real wines compared to model wine due to the matrix effect. Furthermore, the method was successfully applied to investigate the concentration range of lactones and furanones in several icewines, dry red and white wines. Icewines contained higher concentrations of most lactones and furanones compared with dry red and white wines. Partial least squares-discriminate analysis (PLS-DA) also indicated that γ-hexa-, γ-octa-, γ-nona-, γ-deca-, δ-hexa-, and δ-decalactone, as well as 5,6-dihydro-6-pentyl-2H-pyran-2-one (C10 massoia lactone), sotolon and homofuraneol contributed greatly to the discrimination between icewines and dry wines. Moreover, the calculation of odor activity value (OAV) suggested that γ-octa-, γ-nona-, and γ-decalactone, as well as furaneol and homofuraneol contributed greatest to the aroma of icewines., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Fangping green tea (FPGT) produced by Zhonghuang 1 (C. sinensis var. sinensis cv. Zhonghuang 1), a new tea variety, has a classical cooked corn-like aroma, which is completely different from the green tea aroma. In order to illustrate the aroma characteristics of the green tea, the volatiles of FPGT was analyzed with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). The results showed that odor activity value (OAV) of dimethyl sulfide (DMS) was 1195.21 and the odor intensity about DMS was 6.2 in FPGT. Aroma recombination experiment also confirmed the important contribution of DMS to cooked corn-like aroma. Aroma character impact (ACI) values of DMS in tea processed by Zhonghuang 1 and Fudingdabai were 72.01% and 37.86%, respectively. This indicated that the high proportion of DMS was the dominant character of green tea with cooked corn-like aroma. In addition, the S-methylmethionine (SMM) content in fresh leaves of Zhonghuang 1 (0.21 mg/g) was significantly higher than that of Fudingdabai (0.16 mg/g), which was an important reason for high DMS content., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The aroma profile of Semnostachya menglaensis Tsui (S. menglaensis) was identified by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). A total of 29 odor-active compounds, which have aroma intensities ranging from 0.2 ± 0.5 to 10.0 ± 0.0 were detected by GC-O, whereas 14 compounds were detected as important odorants by quantitative analysis and odor activity values (OAVs). An aroma recombination model prepared by mixing 12 odor-active compounds with OAVs ≥ 1 in an "aroma-free" S. menglaensis matrix showed good similarity to the aroma of original S. menglaensis. Omission tests showed that in the overall aroma of S. menglaensis, 2-propionyl-3,4,5,6-tetrahydropyridine, 2-propionyl-1-pyrroline, 1-octen-3-ol, and linalool were the key odorants, and 2-acetyl-3,4,5,6-tetrahydropyridine, 2-propionylpyridine, and α-ionone were also important., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Ester aroma compounds in Chinese Moutai Baijiu were extracted by liquid-liquid extraction (LLE) or headspace solid-phase microextraction (HS-SPME) and identified and quantified by gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS), and 13 of them were recognized as the important aroma compounds based on their flavor dilution (FD) values and odor activity values (OAVs). The perceptual interactions of ethyl isobutyrate and ethyl isovalerate for the overall esters aroma in 53% aqueous ethanol solution were studied through the odor intensity, olfactory threshold and OAV. The Vector Model showed that odor partial addition had occurred after mixing. The Feller's additive model and OAV analysis revealed that various concentrations of ethyl isobutyrate and ethyl isovalerate gave additive or synergistic odor effects for mixtures. In particular, as the concentration of ethyl isobutyrate was increased before mixing, the trend of increasing degree of interaction was observed in the mixture., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2020. Published by Elsevier Ltd.)

Keemun, Assam, Darjeeling and Ceylon black teas are honored as the world's four most famous black teas, and their excellent aroma qualities are well received by people around the world. In this study, aroma components in these four types of teas were analyzed by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) and gas chromatography-olfactometry (GC-O) technologies. A total of 42 aroma-active compounds were ultimately identified, especially benzeneacetaldehyde, geraniol, (Z)-3-hexen-1-yl hexanoate, trans-β-ionone, cis-linalool oxide (pyranoid), hotrienol, and methyl salicylate presented the strongest aroma strengths with pleasant scents in all tested teas. The quantification results indicated that 19 compounds including (Z)-3-hexenol, 1-octen-3-ol, linalool, phenylethyl alcohol, hexanal, benzeneacetaldehyde, limonene, heptanoic acid, (Z)-3-hexen-1-ol, acetate, benzyl alcohol, trans-linalool oxide (furanoid), hotrienol, 1-octen-3-one, 2-nonanone, (E)-2-octenal, nonanal, β-myrcene, 2-pentylfuran, and methylpyrazine were identified as the key compounds with odor activity values (OAVs) higher than 1.0 in the world's four most famous black teas. Notably, the comparison of GC-O and OAV calculation results showed that methyl salicylate (Ceylon), (E)-2-octenal (Assam), benzeneacetaldehyde (Keemun) and linalool and trans-linalool oxide (furanoid) (Darjeeling) might be the most definitive odorants in the corresponding tea categories., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In this study, twenty ester compounds of juiced apples from three different varieties were identified and quantified by gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS) analysis. Six esters were selected as the key odour-active compounds by omission Tests. Perceptual interaction among esters was investigated through odour thresholds and intensity of six esters and fifteen binary mixtures. Most of these mixtures followed an addition behavior. Ethyl butanoate and butyl acetate had a synergistic effect. Sensory analysis revealed that fruity, sour and green notes were enhanced significantly by adding the binary mixture of ethyl butanoate and butyl acetate (E&B). Electronic nose (e-nose) data showed that, compared with the individual ester, the response values of E&B were increased on four sensors. Moreover, with regard to partial least squares regression (PLSR), fruity, sour and green notes attribute covaried well with five sensors of e-nose. The present study would provide a theoretical basis for understanding the aroma characteristic of apple juice, hoping to be helpful for the improvement of apple juice aroma and flavour., (Copyright © 2019. Published by Elsevier Ltd.)

Changes of volatile compounds and sensory properties in the fermentation process of Wuliangye baobaoqu starter (WBS) were determined by sensory analysis, gas chromatography-olfactometry (GC/O) and GC quantitative analyses. The sensory properties of WBS changed from the sour, fruity, bready notes at the temperature-rise phase (3-day and 7-day) to the nutty and moldy notes at the temperature-fall phase (18-day, 21-day and 27-day). Acetic acid, methional, ethyl acetate, phenylethyl alcohol, ethyl 2-phenylacetate, 4-vinylguaiacol were potential aroma active compounds based on their Osme values. Results of GC quantitative analyses showed that the acids had the highest concentration. The concentration of (E)-2-hexenal, ethyl acetate, isoamyl alcohol, phenylethyl alcohol, 2-n-pentylfuran, acetic acid and lactic acid increased with the fermentation time, presented the highest level in the temperature-rise phase and decreased after this period. The concentration of (E,E)-2,4-hexadienal, 2,6-dimethylpyrazine, trimethylpyrazine, tetramethylpyrazine presented the highest level at the temperature-fall phase. Ethyl 3-methylbutanoate, (E,E)-2,4-hexadienal, (E,E)-2,4-nonadienal, acetic acid and butanoic acid had high odor active values. Results of principal component analysis showed that acetic acid, hexanal, (E)-2-hexenal, lactic acid, isoamyl alcohol, 1-hexanol and 1-octen-3-ol were critical volatile chemicals to distinguish different WBS samples., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A chestnut-like aroma is widely considered an important indicator of an excellent-quality green tea; however, the key odorants responsible for chestnut-like aroma have never been systematically studied and remain unknown. In this study, the aroma components of green teas and Chinese chestnuts were analyzed using comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS), and 58 compounds were identified as common aroma components among green teas, boiled Chinese chestnuts, roasted Chinese chestnuts and raw Chinese chestnuts. Subsequently, 17 volatiles, including 3-methylbutanal, (E)-3-penten-2-one, ethylbenzene, heptanal, benzaldehyde, 2-pentylfuran, octanal, benzeneacetaldehyde, (E)-2-octenal, (E,E)-3,5-octadien-2-one, linalool, nonanal, (E)-2-nonenal, decanal, (Z)-hex-3-en-1-yl hexanoate, trans-β-ionone and (E)-nerolidol, were identified as the key odorants responsible for chestnut-like aroma based on the odor activity value (OAV) calculation method. Besides, the comparison of OAVs of key odorants between fresh tea leaves and finished teas indicated that all key odorants were present in fresh tea leaves and that their contents increased or decreased during tea processing. Moreover, the comparison between results of OAV and gas chromatography-olfactometry (GC-O) methods showed that ethylbenzene, heptanal, benzaldehyde, 2-pentylfuran, (E,E)-3,5-octadien-2-one, linalool, (Z)-hex-3-en-1-yl hexanoate and trans-β-ionone were the common identified compounds between the two methods. The identification of chestnut-like aroma in green teas will provide a theoretical basis for further research on the directional adjustment and control of tea aroma quality., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This study investigates the impact of bee pollen on volatile compounds, odour activity values and sensory profiles in Palomino fino and Riesling young white wines. Commercial bee pollen was added to grape must using six different doses (0 (control), 0.1, 0.25, 1, 5, 10 and 20g/L) and fermented under controlled conditions. Volatile compounds were determined with GC and GC-MS chromatography and sensorial analysis using a qualified panel of tasters. Bee pollen produces an increase in volatile compounds depending on the grape variety and the dose applied. It also increases the synthesis of higher alcohols, methanol, esters, acetaldehyde and terpenes, reducing alcohols and fatty acids. Wines with low doses (0.1 and 0.25g/L) showed the higher OAV values (fruity and floral) and scores in overall judgment for the sensory evaluation. High pollen doses decrease fruity character and could result in deviations affecting the sensorial quality., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

One of famous Chinese Baijiu, Gujinggong (GJG) that is produced in Anhui province, belongs to the famous Luzhou-aroma type of Baijiu in regards of its unique flavor characteristics. However, its key aroma-impact volatiles have not been clearly characterized. In this study, a total of 60 aroma compounds of GJG were identified by GC-O and GC-MS, and 35 of them were further recognized as important aroma compounds owing to their OAVs≥1 and sensory evaluation. As a result, its aroma profile was successfully simulated by reconstitution of those 35 and other 11 aroma compounds based on their measured concentrations in the GJG. Moreover, omission test was applied to investigate the effects of the important aroma compounds on the whole aroma profile of GJG. In this context, 9 aroma compounds were confirmed as the key aroma compounds of GJG., (Copyright © 2017 Elsevier Ltd. All rights reserved.)