Solvent-assisted Flavor Evaporation Research Articles

Occurrence and Synthesis Pathways of (Suspected) Genotoxic α,β-Unsaturated Carbonyls in Chocolate and Other Commercial Sweet Snacks.

α,β-Unsaturated carbonyls are highly reactive and described as structural alerts for genotoxicity. Ten of them (either commercially available or synthesized here by combinatorial chemistry) were first investigated throughout the chocolate-making process by solvent-assisted flavor evaporation (SAFE) coupled to GC-MS/SIM. Monitored α,β-unsaturated aldehydes were formed during chocolate production, primarily through aldol condensation of Strecker aldehydes triggered by bean roasting. Notably, levels of 2-phenylbut-2-enal (up to 399 μg·kg-1) and 5-methyl-2-phenylhex-2-enal (up to 216 μg·kg-1) increased up to 40-fold. Dry conching caused evaporation of α,β-unsaturated carbonyls, while wet conching partially restored or increased their levels due to cocoa butter addition. Further analyses showed that α,β-unsaturated aldehydes also occurred in most commercial sweet snacks (up to 16 μg·kg-1), although often at lower concentrations than in roasted cocoa or derived chocolates. In the end, none of the monitored α,β-unsaturated aldehydes did raise a health concern compared to current maximum use levels (2-5 mg·kg-1). On the other hand, much higher levels of genotoxic furan-2(5H)-one were found in crepe and cake samples (up to 4.3 mg·kg-1).

Key odorants of 'Keemun Aroma' and their changes during the preliminary processing of Keemun BLack Tea (Camellia sinensis)

Chinese Keemun black tea (KBT) is one of the most renowned black teas worldwide due to its alluring floral/fruity/honey-like odor. However, the key odorants of the so-called Keemun aroma have not been systematically characterized. A comparative sensory-guided flavor analysis was conducted on the aroma compounds in two orthonasally distinguishable KBTs with high and low grades (HG-KBT and LG-KBT). This well-established methodology included the following steps: volatile collection through solvent-assisted flavor evaporation and headspace solid-phase microextraction, aroma identification based on gas chromatography–olfactometry/mass spectrometry, odor contribution calculation according to stable isotope dilution assay, odor activity values (OAVs), and aroma recombination. A total of 42 odorants were characterized, 16 and 10 of which were regarded as key odorants in HG- and LG-KBT, respectively. Among them, dimethyl sulfide, geraniol, β-ionone, 2-/3-methylbutanal, linalool, and 2-methylpropanal showed the highest OAVs and played a pivotal role in ‘Keemun aroma’. In general, floral odorants had higher OAVs in HG-KBT. In addition, the quantitative changes during the entire preliminary manufacturing step of the tea leaves indicated the great importance of fresh leaves’ quality and withering for the formation of the final aroma quality of the beverage.

Characterization of important odorants from Persian silk tree flowers, Albizia julibrissin

AbstractThe Persian silk tree (Albizia julibrissin) has delicate flowers with a pleasant aroma profile, displaying notes of hyacinth and rose with subtle nuances of citrus, coconut and spice. In this study, a total of 29 odorants were identified in the flowers from a single A. julibrissin selection by the application of a cold‐solvent extraction (CSE), followed by solvent‐assisted flavour evaporation (SAFE) and aroma extract dilution analysis (AEDA). Subsequently, nine odorants with flavour dilution (FD) factors ≥16 were quantitated by stable isotope dilution analysis (SIDA), and odour activity values (OAVs) were calculated. Odorants with OAV ≥1 included 2‐phenylacetaldehyde (OAV 3638), linalool (OAV 797), eugenol (OAV 231), geraniol (OAV 161), 1H‐indole (OAV 93), β‐ionone (OAV 31), 2‐phenylethanol (OAV 11) and γ‐octalactone (OAV 1). An aroma simulation model was prepared based on the quantitation data, and it closely matched the aroma of the flower isolate. Chiral chromatography was performed, and (S)‐(+)‐linalool was the only enantiomer detected. This study advances our understanding of A. julibrissin flower aroma chemistry and lays the groundwork for future investigations for the development of delicate floral aromas for flavour and fragrance applications.

Aroma formation mechanism by the drying step during Congou black tea processing: Analyses by HP-SPME and SAFE with GC-MS

Drying plays a key role in the formation of the final aroma of black tea. However, the contribution to its aroma remains unclear. Herein, headspace solid-phase microextraction (HP-SPME) and solvent-assisted flavor evaporation (SAFE) coupled with GC-MS were used to detect the volatiles of tea samples (before or after drying) from three cultivars. We found that the drying step caused increase in sweet and fruity aromas and decrease in mint-like and green aromas. 89 Differential volatiles were identified with variable importance in projection (VIP) over 1. Furthermore, 25 decreased aroma-active volatiles were obtained with relative odor activity values (rOAVs) over 1, showing that green, flowery, fruity, sweet, and mint-like decreased significantly by 62.27%, 64.88%, 67.56%, 58.26%, and 69.72% after drying step. (Z)-3-Hexen-1-ol (rOAV = 36.93), linalool (rOAV = 301.56) and methyl salicylate (rOAV = 5.50) were the odorants for the green, flowery, fruity, and mint-like odor. Moreover, other 3 increased aroma-active volatiles showed that flowery, fruity, and sweet volatiles increased significantly after drying step. β-Damascenone (rOAV = 43.49) was the main odorant for fruity and sweet aroma. The 28 differential volatiles were associated with carotenoid degradation, lipid degradation, and glycoside hydrolysis. This study reveals the contribution of drying to the aroma formation of black tea.

Characterization of Odorants in a Commercial Culinary Sage (Salvia officinalis L.) and Several Cultivars.

Culinary sage, Salvia officinalis L., is a popular spice plant commonly used throughout the world. In this study, 35 odorants were identified in dried sage via solvent-assisted flavor evaporation (SAFE) and aroma extract dilution analysis (AEDA), including 9 that were identified in sage for the first time. Fifteen odorants were quantitated by stable isotope dilution analysis (SIDA), and their odor activity values (OAVs) were determined. Odorants with high OAVs included (2E,6Z)-nona-2,6-dienal, 1,8-cineole, and β-myrcene. A formulated aroma simulation model closely matched the aroma profile of an aqueous infusion of dried sage. Enantiomeric proportions of selected odorants were determined by chiral gas chromatography. Furthermore, 6 different sage cultivars were grown in the greenhouse, dried under the same conditions, and analyzed. Sensory analysis determined that all cultivars were dominated by an herbaceous sensory attribute and had varying intensities of eucalyptus, mint, clove, pine, green, earthy, floral, and citrus notes. Cultivars with varying intensities of herbaceous, eucalyptus, pine, and green sensory notes correlated with the OAVs of α-thujone/β-thujone, 1,8-cineole, α-pinene, and (2E,6Z)-nona-2,6-dienal, respectively. This study identified the odorants driving the sensory profiles of different sage cultivars and serves as a foundation for future studies on the aroma chemistry of culinary sage.

Diversity of flavour characteristics of table grapes and their contributing volatile compounds analysed by the solvent-assisted flavour evaporation method.

To identify the compounds that contribute to the diverse flavours of table grapes, the flavours and volatile compounds of 38 grape cultivars harvested over 3 years are evaluated through sensory analysis and solvent-assisted flavour evaporation (SAFE). The cultivars are characterized and grouped into seven clusters by hierarchical cluster analysis (HCA) using sensory evaluation data with a flavour wheel specific to table grapes. These clusters were similar to conventional flavour classifications, except that the foxy and neutral cultivars form multiple clusters, highlighting the flavour diversity of table grapes. The SAFE method provides a comprehensive profile of the volatile compounds, including slightly volatile compounds whose profiles are lacking in hybrid grapes and Vitis rotundifolia. The sensory evaluation is supported by the volatile compound profiles, and relationships between the datasets are clarified by multivariate analysis. Specific accumulations and combinations of compounds (α-pinene, β-pinene, phenylethyl alcohol, furaneol, mesifurane, methyl N-formylanthranilate, and mixed ethyl ester and monoterpenoid) were also identified that contribute to the diversity of flavours (fresh green, floral, fruity, fatty green, sweet, fermented/sour) in table grapes, including linalool and linalool analogues (muscat flavour) along with ethyl ester and hydroxyethyl esters (foxy flavour). The accumulation of these compounds was positively related to a higher flavour intensity. Their specific accumulation and combination supported the flavour diversity of table grapes. This study identified novel flavour-associated compound profiles in table grapes through in-depth volatile compound analysis and non-conventional multivariate analysis.

Superior high-efficiency and high-throughput volatile flavor extraction of Japanese fermented seasonings by solvent-assisted stir bar solid extraction with reverse extraction

Fermented seasonings have pleasant flavors that stimulate our appetite. Their flavoring properties change depending on factors such as their materials and fermented conditions. Therefore, a comparative analysis of their flavor is important when evaluating their quality. However, seasonings contain high levels of various matrices such as sugars, proteins, lipids, and ethanol, making it difficult to extract aroma compounds efficiently from them. In this study, we verified a high-efficient and high-throughput volatile flavor analysis of fermented seasonings by solvent-assisted stir bar solid extraction (SA-SBSE) with reverse extraction. We applied SA-SBSE to Japanese fermented seasonings, soy sauce, miso (fermented beans), and mirin (sweet rice wine) and compared their profiles with those from other common extraction methods, headspace gas-solid-phase microextraction (HS-SPME), liquid extraction with solvent-assisted flavor evaporation (LE-SAFE), and conventional SBSE (C-SBSE). The aroma properties and profiles of extracts from SA-SBSE were close to those of the original sample, being similar to that of LE-SAFE. In addition, potent aroma compounds in each sample were extracted by SA-SBSE and LE-SAFE, which were far superior to those by C-SBSE. For quantification, SA-SBSE extracts showed a good standard curve by the standard addition method. We could quantify maltol, one of the most common potent aroma compounds in all samples, for various commercial samples by such high-throughput analysis.

The key aroma components of steamed green tea decoded by sensomics and their changes under different withering degree

Steamed green tea has a long history and unique aroma, but little is known about its key aroma components. In this study, 173 volatiles in steamed green tea were identified using solvent-assisted flavor evaporation and headspace-solid phase microextraction plus two chromatographic columns of different polarities. Aroma extract dilution analysis revealed 48 highly aroma-active compounds with flavor dilution factors 64–1024. Internal standards were used to calculate odorant active value (OAV), and 11 OAV > 1 key aroma compounds were determined. Omission test identified eight substances, including dimethyl sulfide, (E)-β-ionone, cis-jasmone, linalool, nonanal, heptanal, isovaleraldehyde and (Z)-3-hexenol, as the key aroma active compounds of steamed green tea. With the increase of withering degree, the content of these substances increased first and then decreased except for heptanal and cis-jasmone. Moreover, the water content of 62 % was suggested to be an appropriate withering degree during the processing of steamed green tea.

Study on the sweetening mechanism of aroma compounds in yangshan peach using sensory analysis, molecular docking, and molecular dynamics simulation techniques

The demand for sugar reduction in food continues to rise, necessitating innovative approaches to reducing the sugar content without compromising consumer acceptance. The enhancement of odor-induced sweetness represents a promising method for achieving this objective. This study aims to investigate the volatile compounds in peach sourced from Yangshan, using headspace solid-phase microextraction, (HS-SPME), solvent-assisted flavor evaporation, (SAFE), gas chromatography-mass spectrometry (GC-MS), and gas chromatography-olfaction-taste (GC/O-AT) techniques. A total of 75 volatiles were identified by GC-MS, among which 30 volatiles had an aroma activity value ≥ 1. Subsequently, GC/O-AT was employed to screen 15 sweetness-related odors for sensory experiments. The results showed that 13 sweetness-related odorants could significantly enhance sweetness in a 40 g/L sucrose solution. Molecular docking results indicated that in the presence of sucrose, aroma substances can interact with amino acid residues on sweet receptors through hydrogen bonds and hydrophobic interactions. Molecular dynamics (MD) results implied that dihydro-beta-ionone formed hydrophobic interactions with amino acid residues of T1R2; sucrose formed hydrogen bonding interactions and hydrophobic interactions with amino acid residues of T1R2. Overall, the interactions between aroma substances and sweet taste receptors in the presence of sucrose primarily rely on hydrogen bonding and hydrophobic interactions.

Sensomics-Assisted Characterization of Fungal-Flowery Aroma Components in Fermented Tea Using Eurotium cristatum.

Fermented tea (FT) using a single Eurotium cristatum strain can produce a pleasant fungal-flowery aroma, which is similar to the composite aroma characteristic of minty, flowery, and woody aromas, but its molecular basis is not yet clear. In this study, solvent-assisted flavor evaporation and gas chromatography-mass spectrometry/olfactometry were applied to isolate and identify volatiles from the FT by E. cristatum. The application of an aroma extract dilution analysis screened out 43 aroma-active compounds. Quantification revealed that there were 11 odorants with high odor threshold concentrations. Recombination and omission tests revealed that nonanal, methyl salicylate, decanoic acid, 4-methoxybenzaldehyde, α-terpineol, phenylacetaldehyde, and coumarin were the major odorants in the FT. Addition tests further verified that methyl salicylate, 4-methoxybenzaldehyde, and coumarin were the key odorants for fungal-flowery aroma, each corresponding to minty, woody, and flowery aromas, respectively. 4-Methoxybenzaldehyde and coumarin were newly found odorants for fungal-flowery aroma in FT, and 4-methoxybenzaldehyde had not been reported as a tea volatile compound before. This finding may guide future industrial production optimization of FT with improved flavor.

A comparative study on flavor trapping techniques from the viewpoint of odorants of hot-pressed rapeseed oil.

Rapeseed oil, as one of the three major vegetable oils in the world, its matrix effect makes the decoding flavor a challenge. Solid-phase microextraction (SPME), SPME-Arrow, headspace stir bar sorptive extraction (HSSE), direct thermal desorption (DTD), and solvent-assisted flavor evaporation (SAFE) were compared based on the odorants in hot-pressed rapeseed oil. Besides, methodological validation for 31 aroma standards was conducted to compare reliability and robustness of these approaches. DTD showed the largest proportion of acids, while the other techniques extracted a majority of nitriles. The highest number of odorants was detected by SAFE (31), followed by HSSE (30), SPME-Arrow (30), SPME (24), and DTD (14). SPME-Arrow showed the best performance in linearity, recovery, and reproducibility followed by SPME, HSSE, DTD, and SAFE. Results reveal the advantages and limitations of diverse methodologies and provide valuable insights for the selection of extraction methods in an oil matrix and flavor decoding.

Contribution of Key Odorants from Skins, Seeds, and Stems to the Aroma of Chardonnay Marc: A Valuable Coproduct of the Wine Industry.

Chardonnay marc, a co-product of the wine making industry, has recently garnered attention due to its health-promoting properties and is growing in popularity as a potential healthy and flavorful food ingredient. While previous studies have characterized the odorants in marc skins and identified the key odorants in marc seeds, the key odorants in the skins and stems and the contribution of each component to the whole marc aroma remains unknown. In this study, 27 odorants were identified in marc stems using solvent-assisted flavor evaporation and aroma extract dilution analysis. Four odorants were quantitated employing stable isotope dilution assays, and odor activity values (OAVs) were calculated. An odor simulation model prepared using odorants with OAVs > 1 sensorially matched the aroma of the marc stems. Omission studies showed that 3-methylnonane-2,4-dione, ethyl octanoate, oct-1-en-3-one, (2E,4E)-deca-2,4-dienal, (2E,4E)-nona-2,4-dienal, β-ionone, linalool, hexanal, HDMF, and 3-(methylsulfonyl)propanal were the key odorants in marc skins, while hexanal and 3-methylnonane-2,4-dione were the key odorants in marc stems. Mass balance studies suggested that the skins were the main contributor to the hay, floral, and fruity attributes of the whole marc, the seeds contributed mostly to the fatty attribute, and the stems had a minor contribution.

Characterization of Key Odorants in Soy Sauce and Their Concentration Changes during Storage

To explore the key odorants and their concentration changes in high-salt liquid-state fermentation soy sauce (HLFSS) during storage, solvent extraction coupled with solvent-assisted flavor evaporation was applied to isolate the volatiles in HLFSS, and the volatiles were analyzed by gas chromatograph-mass spectrometry-olfactory and gas chromatograph-flame ionization detector-olfactometry combined with the aroma extract dilution assay. A total of 37 odor-active compounds with flavor dilution (FD) factors ranging from 1 to 1024 were identified, and 23 aroma components with odor activity values ≥1 were considered as key odorants. Methional, 3-methylbutanoic acid, phenethyl alcohol, sotolon, 4-hydroxy-2-methyl-5-ethyl-3(2H)-furanone (HEMF), and 4-hydroxy-2,5-dimethylfuran-3(2H)-one (HDMF) had the highest FD factors of 1024. The results of quantitative analysis through the internal standard curve showed that the concentrations of HEMF, HDMF, acetic acid, 1-hydroxy-2-butanone, acetol, and furfuryl alcohol varied greatly during storage, so these compounds might be used as the indicators to determine the shelf life of HLFSS. The recombination experiment also confirmed the important contribution of these compounds. This result will provide valuable information for understanding the flavor changes of HLFSS.

Characterizing and Decoding the Effects of Different Fermentation Levels on Key Aroma Substances of Congou Black Tea by Sensomics.

Fermentation is the key technology for black tea aroma formation. The key aroma substances of black tea at different fermentation stages (unfermented (WDY), underfermented (F1H), fully fermented (F4H), and overfermented (F8H)) were characterized by the methodology of Sensomics. Aroma extract dilution analysis was performed on volatile fractions extracted by using solvent-assisted flavor evaporation and solid-phase microextraction, yielding 93 odor-active areas. Internal standard method plus stable isotope dilution analysis was used for quantitative analysis. The omission experiment identified 23 aroma substances. Further reduction and addition experiments revealed phenylacetaldehyde, (E,E)-2,4-heptadienal, geraniol, linalool, β-damascenone, 2-methylbutyraldehyde, dimethyl sulfide, and isovaleraldehyde with odor activity values (OAV) > 100 as the characteristic aroma components of F4H and also as the main contributors to aroma differences between different fermentation degrees. The green odor of (E,E)-2,4-heptadienal was highlighted in WDY and F1H relative to that in F4H due to the lower contribution of phenylacetaldehyde and β-damascenone in the former two samples. Additionally, excessive OAV increase of fatty aldehydes in F8H masked its similar floral and fruity aroma.

Unveiling improval changes in fried chicken flavor by glucose-curing treatment based on molecular sensory science

To gain insight into the improved flavor changes, the volatile flavor composition of fried chicken with glucose curing (500 mg/100 g meat) (FCWG), exhibiting the strongest meaty and roasted aromas, and that without curing (FCWOG) were comparatively analyzed. Solvent-assisted flavor evaporation combined with gas chromatography–mass spectrometry (GC–MS) and aroma extract dilution analysis by gas chromatography–olfactometry (GC–O), accurate quantitation, and odor-activity values (OAVs) calculation were performed. Both GC–MS or GC–O results revealed that levels of most aroma compounds were increased by the glucose-curing treatment. GC–MS results suggested that the glucose-curing treatment caused increased formation of the flavors via the Maillard reaction and lipid degradation, while the lipid degradation pathway was modified. In addition, GC–O results indicated a higher increase in the formation of the aroma compounds via the Maillard reaction by the glucose-curing treatment. Furthermore, quantitation and odor active values (OAVs) calculation showed glucose-curing had increased formation of the key odorants (OAV ≥ 1) (e.g., bis(2-methyl-3-furyl)disulfide, 2-acetylthiophene, 2-acetylthiazole, (E,E)− 2,4-decadienal, and methional), of which 2-acetylthiophene, bis(2-methyl-3-furyl)disulfide, and (E,E)− 2,4-decadienal are vital in fried chicken flavor. The results can provide guidance for improving fried chicken flavor by marination.

Investigation on the changes of odor-active compounds of Amomum tsao-ko during natural drying

To characterize the key odorants in Amomum tsao-ko (AT) and to investigate their changes during natural drying, volatile compounds of AT were extracted and analyzed by solvent extraction combined with solvent-assisted flavor evaporation and gas chromatographymass spectrometry–olfactometry. A total of 41 aroma-active compounds with flavor dilution factors ranging from 3 to 6561 were identified in AT. Fourteen odorants were determined to be the key odorants by quantitation analyses, odor activity value (OAV) calculations, recombination and omission experiments. To further investigate the changes in aroma components in AT during natural drying, the concentrations and OAVs of odor-active compounds were measured at 0, 2, 4, 6, 8, 12, 16, and 20 days. The results showed that the number of aroma-active components did not change during natural drying, but their content changed with different trends. The concentration of geraniol showed a continuous upward trend; those of hexanal, octanal, nonanal and pinocarvone decreased first and then increased; those of α-pinene, sabinene, 2-nonanone, (E)-2-octenal, 2-nonanol, 4-terpineol, epidolichodial and (E,E)-2,4-dodecadienal changed on a fluctuating trend, while those of the other 28 compounds showed a trend of first increasing and then decreasing. These results provide a theoretical basis for further utilization of AT.

Characterization of Volatile Flavor Compounds in Dry-Rendered Beef Fat by Different Solvent-Assisted Flavor Evaporation (SAFE) Combined with GC-MS, GC-O, and OAV.

To comprehensively understand the volatile flavor composition of dry-rendered beef fat, solvent-assisted flavor evaporation (SAFE) with four extraction solvents (dichloromethane, pentane, ethyl ether, and methanol) combined with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactormetry (GC-O) were performed. GC-MS analysis found 96 different volatile compounds in total using the four extraction solvents. According to the GC-MS results and the heat map and principal component analysis (PCA), most of the volatile compounds resulted from dichloromethane and pentane extraction, followed by ethyl ether. Methanol extraction found a few volatile compounds of higher polarity, which was supplementary to the analysis results. Moreover, GC-O analysis found 73 odor-active compounds in total using the four extraction solvents. The GC-O results found that pentane and dichloromethane extraction had a significantly larger number of odor-active compounds than ethyl ether and methanol extraction. This indicated that pentane and dichloromethane were more effective solvents for the extraction of odor-active compounds than the other two solvents. Finally, a total of 15 compounds of odor-active values (OAVs) ≥ 1 were determined to be the key aroma compounds in the dry-rendered beef fat, including 2-methyl-3-furanthiol, 3-methylthiopropanal, (E,E)-2,4-nonadienal, 12-methyltridecanal, and 1-octen-3-one.

Quantification of odorous and potentially harmful substances in acrylic paint

Within this study sixteen odour active substances (1-butanol, butyl acetate, 3-methyl-4-heptanone, butyl acrylate, styrene, ethylbenzene, propylbenzene, cumene, sec-butylbenzene, benzaldehyde, 2-ethylhexyl acrylate, naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 1,2-dimethylnaphthalene, 1,7-dimethylnaphthalene), that have previously been identified in acryl paints were quantified in ten black acrylic paint samples using GC-GC-MS (heart-cut two-dimensional gas chromatography-mass spectrometry) after prior extraction and purification via solvent assisted flavour evaporation. In this case, the preceding analysis of the most abundant odour active volatiles via GC-O (gas chromatography-olfactometry) provided indications on which smell properties might be linked with elevated and concerning levels of possibly harmful substances. Based on that work, four samples raised attention due to their mainly repelling or unpleasant odour with mainly aromatic, solvent-like, mothball-like or geranium-like smell impressions. The remaining samples either showed fruity/fermented, fruity/apple juice-like, mushroom-like or cocoa-like/earthy odour qualities. The repelling and unpleasant odour was generally linked to naphthalene or benzene derivatives that are of concern with regard to being potential carcinogens. With concentrations ranging as high as from 3.75 mg/kg to 143.41 mg/kg, n-butanol was found to be the odour active substance with the highest concentrations in all but one paint sample. The results showed that all paints contain different and specific patterns of the analysed odour active substances and volatiles. Whereas only two samples revealed no elevated concentration of any of the quantified substances, two samples (A9 and A10) showed elevated levels for all or nearly all substances. The concentrations for single substances were generally lower than the recommended exposure limit and therefore unlikely to cause any adverse effects with regards to toxicity and irritation as single constituents. However, as a group of substances these might exert adverse health effects due to combined or synergistic effects. Based on these observations, the occurrence of combinations of potentially carcinogenic substances in products which are occupationally used on a daily basis or are in direct skin contact should thus be regarded with care in the future.

Comparative study on key odorants of Jiujiang Fenggang Huangjiu and their succession regularities during aging using sensory-directed flavor analysis

Huangjiu was a Chinese national alcohol with a unique flavor. The key odorants in Jiujiang Fenggang Huangjiu (JJFG) and their succession regularities during aging were systematically researched by a sensomics analysis approach. The volatiles of JJFG were isolated by solvent-assisted flavor evaporation, 77 odorants were identified using gas chromatography–olfactometry-mass spectrometry combined with odor-specific magnitude estimation. Three aroma recombinants, prepared using odorants with odor activity values ≥ 1, all showed good similarities with their corresponding samples (92.1%∼97.5%). After omission/addition tests, 7 new key aroma compounds were found in JJFG, including 1-octen-3-one, 1-pentanol, guaiacol, ethyl 2-hydroxy-4-methylpentanoate, 2-phenethyl acetate, ethyl butanoate, and (E,Z)-2,6-nonadienal. Using orthogonal partial least squares-discriminant analysis, 20 compounds with VIP ≥ 1 were found to be important indicators during aging of JJFG. Among them, sotolon, 3-methylsulfanylpropanal, et al. increased with aging. The improved solid-phase extraction can effectively quantify sotolon, with a recovery rate of 80.96%∼91.75%.

Characterization of the key odorants in fresh Amomum tsao-ko Crevost et Lemaire fruit by gas chromatography-olfactometry, quantitative analysis and aroma reconstitution

To decode key odorants (KOs) in fresh Amomum tsao-ko Crevost et Lemaire fruit (FAF) and investigate the effect of isolation methods on KOs and enantiomer ratios, volatiles were isolated using both direct solvent extraction combined with solvent-assisted flavor evaporation (DSE-SAFE) and hydrodistillation (HD) and analyzed by gas chromatography‒mass spectrometry/olfactometry. In total, 55 odor-active compounds with flavor dilution factors between 1 and 8192 were identified, of which 36 and 39 odorants were detected in the SAFE and HD isolates, respectively. By quantitative analysis and odor activity value calculation, 22 odorants in the SAFE isolate and 25 odorants in the HD isolate were determined to be FAF KOs. The differences in the concentrations and the number of KOs caused the two isolates to have different odor characteristics. The recombination experiment further confirmed the results. Among the three studied chiral odorants, including linalool, 4-terpenol, and α-terpineol, the (S)-(−)-enantiomer was dominant, and the (S)-(−)-enantiomer inverted into the (R)-(−)-enantiomer during HD.