Aroma Extract Research Articles

Influence of liquid polybutadiene on crosslinking network and mechanical properties of SSBR/BR

AbstractThe treated distillate aromatic extract (TDAE) is widely used in tread compounds. However, polycyclic aromatic hydrocarbons (PAHs) contained in TDAE is serious harm to the environment and human. In this paper, liquid polybutadiene (LPB) of different brands was used to replace TDAE to plasticize solution polymerized styrene‐butadiene rubber/cis‐1,4‐polybutadiene rubber (SSBR/BR). The effects of liquid polybutadiene instead of TDAE on crosslinking network and mechanical properties of matrix rubber were studied. LPB could participate in vulcanization reaction (different from TDAE). The results showed that LPB effectively reduced the critical strain amplitude of Payne effect (ameliorated filler dispersion) compared with TDAE plasticizing SSBR/BR. The degree of crosslinking decreased slightly, but there was no significant difference in rolling resistance and wet skid resistance at the same sulfur content. Changing the sulfur content, the wet skid resistance of tread and tensile strength of SSBR/BR vulcanizate plasticized by LPB were significantly improved, and the effect of LPB with high 1,2‐vinyl content was better. In a word, LPB as a new environmental protection plasticizer can be used to effectively replace the TDAE plasticizing SSBR/BR.

Effects of aromatic compounds on movement activity of Pyrrhocoris apterus in the conditions of a laboratory experiment

In the conditions of an urban environment, insects, including Pyrrhocoris apterus (Linnaeus, 1758) (Hemiptera, Pyrrhocoridae), are subject to dozens of volatiles: solvents, food flavorings, cosmetic products. For firebugs, some attract them, some scare them off, and to some they are indifferent. In this article, in the conditions of laboratory experiment, we evaluated the influence of chemical substances on rates of movement of firebugs. Under the influence of the substances we studied, there occurred no significant increase or decrease in the activity of firebugs. The most significant effect on rates of movement of firebugs was exerted by solvent, white spirit and solvent 646 p – firebugs travelled 12 cm distance for 24.2%, 49.6% and 58.7% of the time the control group did. Movement activity of firebugs was insignificantly decreased by aromatic extracts Royаl milk extract, Butcher’s broom extract and chrysalis oil: firebugs travelled 12 cm distance for 132.7%, 135.2% and 146.8% of time the control group. Aromatic substances likely interact with receptors on antennae of firebugs, and therefore the insects need additional time for orienting reactions, deciding whether those substances signal presence of potential food objects in the accessibility zone.

Characterization of the key aroma compounds in aged Chinese Xiaoqu Baijiu by means of the sensomics approach

The aromatic characteristics of Xiaoqu Baijiu differ noticeably and were investigated using the sensomics approach. Aroma extract dilution analysis revealed more aroma-active compounds in aged Xiaoqu Baijiu than fresh Xiaoqu Baijiu, with 55 compounds identified with flavor dilution (FD) factors of ≥8. Using sensomics, 51 odorants were identified as important aroma compounds in aged Xiaoqu Baijiu. Omission models suggested that 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolon), vanillin, and 3-(methylthio)propionaldehyde (methional) played critical roles in the overall aroma characteristics of aged Xiaoqu Baijiu. Furthermore, 1,1-dimethoxyethane, 3-methylbutanal, dimethyl trisulfide, ethyl acetate, and ethyl isovalerate also exhibited significant roles in the aroma characteristics of aged Xiaoqu Baijiu. This work may provide a better understanding on Chinese Xiaoqu Baijiu and the changes of aroma compounds during the aging process of liquor.

Detection of odor difference between human milk and infant formula by sensory-directed analysis

Infants who accustomed to consume human milk can hardly adapt to the odor of infant formula in a short time and prefer the odor of human milk. In this study, the sensory-directed analysis was used to investigate the odor differences between human milk and infant formula. Aroma extraction dilution analysis (AEDA) results showed that carbonyl compounds and alcohols were the most important components with the higher dilution factors (FD) in human milk and infant formula. There were 14 key aroma active compounds (OAV ≥ 1) in human milk, like octanal, linalool, benzaldehyde, and furfural, while 11 in infant formula, like hexanal, 1-octen-3-one, (E)-2-octenal, and octanal. The aroma recombination and omission experiment further revealed that compounds such as (E)-2-decenal, linalool, 2-furanmethanol, 2-pentylfuran, (E,E)-2,4-heptadienal, nonanal, (E)-2-nonenal, and 1-octen-3-one were the major reason for the odor difference between human milk and infant formula.

Aroma characterization and their changes during the processing of black teas from the cultivar, Camellia sinensis (L.) O. Kuntze cv. Jinmudan

Jinmudan (JMD) black tea is processed from the JMD cultivar (Camellia sinensis (L.) O. Kuntze cv. Jinmudan). Dried JMD black tea (JMD-D) received a score of 7.43 in the quantitative descriptive analysis, indicating that it had the strongest fruity flavor. Many volatile compounds (129) were identified by solvent assisted flavor evaporation and gas chromatograph mass spectrometry. In total, 26 aroma active compounds, including (Z)-methyl epi-jasmonate (flavour dilution factor (FD): 128–1024), benzeneacetaldehyde (FD: 512–1024), linalool (FD: 256–1024), geraniol (FD: 256–512), jasmine lactone (FD: 64–1024), were identified in JMD-D and controls through an aroma extract dilution analysis and gas chromatography-mass spectrometry olfactometry. On the basis of the FD values, odor activity values, and relative quantification results, the volatiles of fruit flavor derived from lipids, such as jasmine lactone, were prominent in JMD-D compared to the controls. During the processing of the four types of black tea, the volatile fraction concentration increased mainly from the fresh leaf to the fermentation stage and decreased in the drying stage.

SAFE and SBSE combined with GC-MS and GC-O for characterization of flavor compounds in Zhizhonghe Wujiapi medicinal liquor.

Volatile compounds in Chinese Zhizhonghe Wujiapi (WJP) medicinal liquor were extracted by solvent-assisted flavor evaporation extraction (SAFE) and stir bar sorptive extraction (SBSE), respectively, and identified by gas chromatography-mass spectrometry. Results showed that a total of 123 volatile compounds (i.e., 108 by SAFE, 50 by SBSE, and 34 by both) including esters, alcohols, acids, aldehydes, ketones, heterocycles, terpenes and terpenoids, alkenes, phenols, and other compounds were identified, and 67 of them were confirmed as aroma-active compounds by the application of the aroma extract dilution analysis coupled with gas chromatography-olfactometry. After making a simulated reconstitute by mixing 41 characterized aroma-active compounds (odor activity values ≥1) based on their concentrations, the aroma profile of the reconstitute showed good similarity to that of the original WJP liquor. Omission test further corroborated 34 key aroma-active compounds in the WJP liquor. The study of WJP liquor is expected to provide some insights into the characterization of special volatile components in traditional Chinese medicine liquors for the purpose of quality improvement and aroma optimization.

Life cycle energy and carbon emissions of essential oil extraction from Rosemary

The search for essential oils from aromatic plants has been growing worldwide due to its potential applications in the food, cosmetic and pharmaceutical industries. This work aims to evaluate the life cycle’s primary energy and carbon emissions of essential oil extraction from Rosemary grown in Portugal, following the LCA methodology. Two different functional units, 1 g of aromatic extract and 1 g of α-pinene, were selected for the study. Life cycle inventory data were mainly obtained from lab scale experiments, comparing three essential oil extraction processes, based on hydro-distillation (HD), HD followed by lyophilization (L) and supercritical fluid extraction (SFE). Results show that for the fresh samples, SFE is the best extraction method, with 290 MJ and 15 kg CO2-eq of energy and carbon emissions per 1 g of aromatic extract, while for dried samples the HD is preferable, with respectively 166 MJ and 8 kg CO2-eq per 1 g of aromatic extract. On the other hand, for obtaining 1 g α-pinene the HD is the best method with 465 and 1398 MJ of energy and 23 and 69 kg CO2-eq of carbon emissions, for respectively the fresh and dried samples.

Sensomics-assisted flavor decoding of coarse cereal Huangjiu

Huangjiu is one of China’s national alcoholic beverages. The key odorants in four coarse cereal Huangjius (CCH) were identified by sensomics approach. Eighty-eight odorants were identified using solvent-assisted flavor evaporation combined with gas chromatography–olfactometry/spectrometry and aroma extract dilution analysis. Four aroma recombinates showed good similarities to the corresponding original aroma profiles (93.27–96.97%). Partial least squares regression analysis predicted vanillin and β-damascenone were the main causes of the aroma differences in the four CCHs. For the first time, omission and addition tests showed that β-damascenone caused the sweet and tea leaf aromas, whereas hexanal, nonanal, and 2-methyl-3-(methyldisulfanyl)furan contributed to the cooked grain aroma. Finally, 2-phenylethanol, ethyl (E)-3-phenyl-2-propenoate, ethyl 3-phenylpropanoate, vanillin, 3-(methylsulfanyl)propanal, γ-nonalactone, sotolon, β-damascenone, hexanal, nonanal, and 2-methyl-3-(methyldisulfanyl)furan were confirmed as the key odorants in the CCHs. 2-Methyl-3-(methyldisulfanyl)furan was a newly identified key odorant in Huangjiu.

Flavor deterioration of Mandarin juice during storage by MDGC-MS/O and GC-MS/PFPD

Commercial mandarin juice often exhibits flavor deterioration during storage. The changes in volatile flavor profiles were investigated in mandarin juice stored under three different temperature conditions (4 °C, 25 °C, and 40 °C). The application of multidimensional gas chromatography-mass spectrometry/olfactometry (MDGC-MS/O) coupled with aroma extract dilution analysis (AEDA) identified 31 odorants in stored mandarin juice, including seven off-flavor contributing compounds: methanethiol (unpleasant, repulsive), dimethyl sulfide (sulfur, cabbage), methional (cooked potato), p-cymene (solventy), 4-vinylguaiacol (medicine), terpinen-4-ol (wood), and α-terpineol (floral, mint). 4-Vinylguaiacol was also identified in mandarin juice for the first time. In addition, 64 volatile compounds determined by GC-MS/pulsed flame photometric detector (GC-MS/PFPD) were classified as alcohols, terpenes, volatile sulfur compounds (VSCs), aldehydes, esters, ketones, and phenols. Volatile compound differences were observed in mandarin juice under different storage conditions by heat-map generation and principal component analysis (PCA). The results revealed that high-temperature storage led to a rapid increase in the concentration of total alcohols and VSCs. Furthermore, the flavor deterioration markers α-terpineol and dimethyl sulfide were identified based on off-flavor contribution and variable importance in projection (VIP) (score >1) values in the PLS-DA model. These two compounds are valuable for marker-assisted flavor deterioration analysis in mandarin juice during storage.

Identification of the influential odorants for the unpleasant rancid smell of ripe noni fruit (Morinda citrifolia)

SummaryIn this study, the volatile changes of noni fruit in various ripening stages were analysed using gas chromatography–mass spectrometry. Eleven of the 35 identified volatiles were found odour‐active through gas chromatography–olfactometry. Based on the aroma extract dilution analysis, hexanoic acid, octanoic acid and their methyl esters were considered as the key odorants for the smell of noni fruit. Results also indicated that the sensory perception of the rancid smell was resulted from the antagonistic effects of the key acid and methyl ester odorants. This study may facilitate the improvement of the acceptability of noni processed foods in the future.

Influence of Allium Sativum (Garlic), Zingiber officinale (Ginger) and Syzygium aromaticum (Clove) Extract against Larvae of Aedes mosquitoes (Culicidae: Diptera)

Mosquito control has become more difficult due to the unsystematic use of synthetic chemical insecticides which have inauspicious effect on the environment. Botanical phyto-chemicals with mosquitocidal potential are now recognized as potent alternative insecticides to replace synthetic insecticides in mosquito control programs due to their excellent larvacidal activities. The present study assessed the influence of A. sativum (garlic), Z. officinale (ginger) and S. aromatic (clove) extracts against Aedes mosquitoes. Larvacidal activities of three indigenous plant extracts were studied in the range 5.0 to 30.0mg/l in the laboratory bioassay against fourth instar larvae of Aedes sp. The mortality were subjected to probit analysis to determine the lethal concentration (LC50) to kill 50 percent of treated larvae of Aedes sp. Data obtained were analyzed by Comparing experimental groups and control groups with significance level established at p<0.05. All plants tasted showed effects after 24hrs of exposure at different concentration (mg/l). However the highest mortality was found in A. Sativum (garlic) and Z. officinale (ginger) against larvae of Aedes mosquitoes with LC50 = 42.50% (2.685) and LC50 = 30.01% (4.461) mg/l, while S. aromatic(clove) was found to have lowest mortality at LC50 = 24.50% (5.52) respectively. It is therefore recommended that A. sativum(Gallic), S. aromatic (Clove) has showed larvacidal effects against Aedes mosquitoes and could be served as alternative form of botanical control against mosquitoes .
 Keywords: A. sativum (garlic), Z. officinale (ginger) and S. aromatic (clove), Extracts, Aedes mosquitoes

Pulsed Electric Field-Assisted Extraction of Aroma and Bioactive Compounds From Aromatic Plants and Food By-Products.

In this work, the effect of pulsed electric field (PEF) pre-treatment on the extractability in green solvents (i. e., ethanol–water mixture and propylene glycol) of target aroma and bioactive compounds, such as vanillin from vanilla pods, theobromine and caffeine from cocoa bean shells, linalool from vermouth mixture, and limonene from orange peels, was investigated. The effectiveness of PEF as a cell disintegration technique in a wide range of field strength (1–5 kV/cm) and energy input (1–40 kJ/kg) was confirmed using impedance measurements, and results were used to define the optimal PEF conditions for the pre-treatment of each plant tissue before the subsequent solid–liquid extraction process. The extracted compounds from untreated and PEF-treated samples were analyzed via GC-MS and HPLC-PDA analysis. Results revealed that the maximum cell disintegration index was detected for cocoa bean shells and vanilla pods (Zp = 0.82), followed by vermouth mixture (Zp = 0.77), and orange peels (Zp = 0.55). As a result, PEF pre-treatment significantly enhanced the extraction yield of the target compounds in both solvents, but especially in ethanolic extracts of vanillin (+14%), theobromine (+25%), caffeine (+34%), linalool (+114%), and limonene (+33%), as compared with untreated samples. Moreover, GC-MS and HPLC-PDA analyses revealed no evidence of degradation of individual compounds due to PEF application. The results obtained in this work suggest that the application of PEF treatment before solid–liquid extraction with green solvents could represent a sustainable approach for the recovery of clean labels and natural compounds from aromatic plants and food by-products.

Mechanism of Extractive Separation of Light Cycle Oil Using a Deep Eutectic Solvent Composed of Tetrabutylphosphonium Bromide and Levulinic Acid

To achieve maximum usage and economically upgrade light cycle oil, it is necessary to separate light cycle oil components into nonaromatic and aromatic fractions. A deep eutectic solvent composed of tetrabutylphosphonium bromide and levulinic acid exhibited excellent extraction performance in separating light cycle oil components. In this work, the mechanisms of deep eutectic solvent formation and light cycle oil separation are investigated using characterization analysis and molecular dynamics simulations. Both Fourier-transform infrared spectra and molecular dynamics simulation results indicate that the main driving force for deep eutectic solvent formation is hydrogen-bonding interactions between the Br– anion of tetrabutylphosphonium bromide and the carboxyl group (−COOH) of levulinic acid. On the other hand, while the TBP+ cation of tetrabutylphosphonium bromide and the carbonyl group (−C═O) of levulinic acid are less likely to contribute to deep eutectic solvent formation, they are more likely to interact with the aromatic ring of tetralin via CH−π and π–π interactions, respectively. The results suggest that each functional group of tetrabutylphosphonium bromide and levulinic acid plays an essential role either in deep eutectic solvent formation or in aromatic compound extraction, which provides insights into the mechanism of extractive separation of light cycle oil components using deep eutectic solvents.

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.

Effect of Wort Boiling on Volatiles Formation and Sensory Properties of Mead.

Mead is an alcoholic beverage based on bee honey, which can be prepared in different variations such as modified honey-water compositions, the addition of spices, and the use of different yeast strains. Moreover, the technological process of mead production such as the step of wort preparation (with or without boiling of wort before fermentation) can be modified. All these factors might have a significant impact on the formation of aroma-active compounds, and therefore, sensory acceptance by consumers. High vacuum distillation, using the so-called solvent assisted flavor evaporation (SAFE) technique, or headspace-solid phase microextraction (HS-SPME) were applied for the isolation of the odorants. A sensory profile was used to monitor the changes in the aroma of the mead samples. Twenty-eight aroma-active compounds were detected during aroma extract dilution analysis (AEDA) based on gas chromatography-olfactometry (GC-O) and were finally identified by gas chromatography-mass spectrometry (GC-MS) using authentic reference compounds, including methyl propanoate, methyl 3-(methylthio)propanoate, and methional, all of them were identified for the first time in mead. Compounds with high flavor dilution (FD) factors were quantitated via stable isotope dilution analysis (SIDA) and revealed ethyl acetate (16.4 mg/L) to be the most abundant volatile compound, increasing to 57 mg/L after wort boiling, followed by ethyl hexanoate (both 1.2 mg/L). Furthermore, key aroma compounds were esters such as ethyl hexanoate, ethyl octanoate, and ethyl 3-methylbutanoate. The sensory panel evaluated ethanolic, honey-like, clove-like, sweet, and fruity notes as the main aroma descriptors of mead. The significant change in sensory evaluation was noted in the sweet odor of the heat-treated mead.

Obtaining Aromatic Extracts from Portuguese Thymus mastichina L. by Hydrodistillation and Supercritical Fluid Extraction with CO2 as Potential Flavouring Additives for Food Applications.

Humans often respond to sensory impulses provided by aromas, and current trends have generated interest in natural sources of fragrances rather than the commonly used synthetic additives. For the first time, the resulting aroma of a selected culture of Thymus mastichina L. was studied as a potential food ingredient. In this context, dried (DR) and fresh (FR) samples were submitted to carbon dioxide (CO2) supercritical extraction (SFE) and hydrodistillation (HD) methods. The extracts were characterised according to their volatile composition by GC-MS, cytotoxicity against a non-tumour cell culture, and sensory attributes (odour threshold and olfactive descriptors). The most abundant aromas were quantified, and the analysis performed by GC-MS revealed an abundance of terpenoids such as thymol chemotype, followed by the precursors α-terpinene and p-cymene. DR and FR extracts (EX) obtained from SFE-CO2 show the highest content of thymol, achieving 52.7% and 72.5% of the isolated volatile fraction. The DR essential oil (EO) contained the highest amount of terpenoids, but it was also the most cytotoxic extract. In contrast, SFE-CO2 products showed the lowest cytotoxic potential. Regarding FR-OE, it had the lowest extraction yield and composition in aroma volatiles. Additionally, all samples were described as having green, fresh and floral sensory notes, with no significant statistical differences regarding the odour detection threshold (ODT) values. Finally, FR-EX of T. mastichina obtained by SFE-CO2 presented the most promising results regarding food application.

Changes in key aroma-active compounds and sensory characteristics of sunflower oils induced by seed roasting.

This study investigated the changes in aroma composition and perception of sunflower oils induced by seed roasting using sensory-oriented flavor analysis. Volatile compounds were extracted by solvent-assisted flavor evaporation and headspace solid-phase microextraction. Odorants were characterized by gas chromatography-olfactometry-mass spectrometry and aroma extract dilution analysis. The cold-pressed and roasted sunflower oils contained 13 and 50 odorants, respectively, with the flavor dilution factors between 1 and 256. Fifty-six odorants were newly identified in sunflower oils. Quantification of 26 important odorants by the external standard method revealed apparent changes induced by seed roasting in loss of terpenes, formation of Maillard reaction products, and the increase in lipid oxidation products. The most important odorants (odor active values, OAVs=1-1857) in the cold-pressed sunflower oil included α-pinene (11,145µg/kg), β-pinene (4068µg/kg), linalool (56µg/kg), hexanal (541µg/kg), octanal (125µg/kg), α-phellandrene (36µg/kg), and (E)-2-octenal (69µg/kg), contributing to the raw sunflower seed, woody, green, earthy, and sweet aromas of the oil. The most important contributors (OAVs=1-884) to the roasted, smoky, and burnt aromas of the roasted sunflower oil were 2- and 3-methylbutanal (6726 and 714µg/kg), 2,6-dimethylpyrazine (2329µg/kg), 2,5-dimethylpyrazine (12,228µg/kg), 2,3-dimethylpyrazine (238µg/kg), 2,3-pentanedione (1456µg/kg), 2-pentylfuran (1332µg/kg), 2,3-dimethyl-5-ethylpyrazine (213µg/kg), and 1-pentanol (693µg/kg). Aroma recombination of the key odorants in odorless sunflower oil adequately mimicked the general aroma profiles of sunflower oils. This study provides an important foundation for understanding the relationship between oil processing and aroma molecules of sunflower oils. PRACTICAL APPLICATION: The clear changes observed in the composition and concentrations of key aroma compounds explained the changes in sensory characteristics of sunflower seed oils induced by seed roasting on a molecular basis. Characterizing the key aroma-active composition of sunflower oil and investigating its relationship with oil processing could provide important practical applications for the sunflower oil industry in flavor regulation, quality control, product development, and process optimization.

Production of an Anise- and Woodruff-like Aroma by Monokaryotic Strains of Pleurotus sapidus Grown on Citrus Side Streams.

The production of natural flavors by means of microorganisms is of great interest for the food and flavor industry, and by-products of the agro-industry are particularly suitable as substrates. In the present study, Citrus side streams were fermented using monokaryotic strains of the fungus Pleurotus sapidus. Some of the cultures exhibited a pleasant smell, reminiscent of woodruff and anise, as well as herbaceous notes. To evaluate the composition of the overall aroma, liquid/liquid extracts of submerged cultures of a selected monokaryon were prepared, and the volatiles were isolated via solvent-assisted flavor evaporation. Aroma extract dilution analyses revealed p-anisaldehyde (sweetish, anisic- and woodruff-like) with a flavor dilution factor of 218 as a character impact compound. The coconut-like, herbaceous, and sweetish smelling acyloin identified as (2S)-hydroxy-1-(4-methoxyphenyl)-1-propanone also contributed to the overall aroma and was described as an aroma-active substance with an odor threshold in air of 0.2 ng L−1 to 2.4 ng L−1 for the first time. Supplementation of the culture medium with isotopically substituted l-tyrosine elucidated this phenolic amino acid as precursor of p-anisaldehyde as well as of (2S)-hydroxy-1-(4-methoxyphenyl)-1-propanone. Chiral analysis via HPLC revealed an enantiomeric excess of 97% for the isolated product produced by P. sapidus.

Free versus droplet-bound aroma compounds in sparkling beverages

The initial experience of a beverage’s flavor after opening the bottle is created by a combination of the gas phase and droplet-bound odorants. However, most studies do not consider this combination, and focus on the odor-active components in the liquid or gas phase, separately. To cover this aspect, a filter from pyrolyzed polyacrylonitrile fiber was packed inside thermal desorption unit liner and used for trapping droplet-bound odorants. Additionally, polydimethylsiloxane coated thin-film was applied for extraction of gas-phase aroma. Following trapping/extraction, the devices were desorbed and compounds were separated using GC–MS. The odorants in commercial sparkling beverages were quantified immediately after opening the bottle to mimic real-life conditions of the consumer’s experience of the flavor. The reported results provide a more comprehensive understanding of flavor perception in effervescent drinks by considering both gas and droplet phase.

Characterization of the key aroma-active compounds in high-grade Dianhong tea using GC-MS and GC-O combined with sensory-directed flavor analysis

Dianhong tea (DHT) is popular for its pleasant caramel-like aroma. In this study, the aroma profile of high-grade DHT have been studied using gas chromatography-mass spectrometry (GC-MS) and gas chromatography–olfactometry (GC-O) combined with headspace solid phase microextraction (HS-SPME). A total of 52 aroma-active compounds were identified by GC-O coupled with aroma extract dilution analysis (AEDA) and odor specific magnitude estimation (Osme). Among them, quantification of 21 aroma-active compounds indicated that the content of linalool (5928 µg/kg) was the highest in high-grade DHT, followed by phenylethanol (3923 µg/kg) and phenylacetaldehyde (1801 µg/kg). Sensory-directed aroma recombination and omission tests further verified that phenylacetaldehyde, linalool, geraniol and 3-ethyl-2,5-dimethylpyrazine were important contributors to the overall sensory characteristics of high-grade DHT which dominated mainly by floral, sweet and caramel-like odors. This work will provide a theoretical reference for comprehensively understanding the aroma characteristic of DHT.