Aroma Recombination Research Articles

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 the key odorants in kurut with aroma recombination and omission studies

Kurut is a traditional acid-coagulated cheese from the northwest region of China. Using gas chromatography olfactometry and aroma extract dilution analysis, we identified 21 potent odorants from kurut within the flavor dilution factor range of 8 to 256. We developed a kurut matrix to determine the odor thresholds of key aroma compounds in kurut. The odor activity values of these 21 potent volatile compounds revealed that 18 were present at concentrations above their odor threshold values and therefore contributed to the overall aroma of kurut. The result of aroma recombinant experiments prepared by mixing the 18 most important odorants at the concentrations in which they occurred in kurut showed that the overall aroma profile of the recombinant sample was very similar to that of kurut. Omission experiments indicated that acids, furans, esters, and ketones were the most important volatile compounds in kurut. Some aroma compounds-such as butanoic acid, homofuraneol, ethyl hexanoate, and ethyl butanoate-play the most important roles in the overall flavor profile of kurut. Some odorants with a high flavor dilution factor, such as sulfur compounds, may have little effect. The study of key aroma compounds in kurut could provide important information for researching and developing traditional Chinese cheese products.

Identification of Key Off-Flavor Compounds in Thermally Treated Watermelon Juice via Gas Chromatography-Olfactometry-Mass Spectrometry, Aroma Recombination, and Omission Experiments.

Thermally treated watermelon juice (TW) presents a strong unpleasant smell, resulting in poor consumer acceptance. It is necessary to identify the key off-flavor compounds in TW. Solid-phase microextraction (SPME) and solvent-assisted flavor evaporation (SAFE) coupled with gas chromatography–olfactometry–mass spectrometry (GC–O–MS) were applied to the extraction and analysis of the volatile compounds in TW. Five aroma-active compounds and seven off-flavor compounds were quantitatively analyzed by the standard curve method. Based on the flavor dilution factor (FD), odor attribute, odor activity value (OAV) of volatile compounds, and partial least-squares regression (PLSR) analysis, seven key off-flavor compounds were preliminarily identified as follows: (E)-2-heptenal, decanal, octanol, diisopropyl disulfide, hexanol, (E)-2-decenal, and (E)-2-octenol. Aroma recombination proved that these off-flavor compounds above had a negative impact on the overall flavor in TW. Omission experiments were taken to confirm them further. Finally, octanol, diisopropyl disulfide, and (E)-2-decenal were identified as the most potent off-flavor compounds in TW.

Characterization of the key aroma compounds in Semnostachya menglaensis Tsui by gas chromatography-olfactometry, odor activity values, aroma recombination, and omission analysis.

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.

Identification of aroma compounds in pea protein UHT beverages

The objective of the study was to characterize changes in the aroma profile of pea protein beverage during Ultra High Temperature (UHT) processing and subsequent refrigerated storage. The aroma profiles were characterized using Gas Chromatography/Mass Spectrometry/Olfactometry (GC/MS/O); twenty-one aroma compounds were identified and further quantified using dynamic headspace-GC/MS/MS analysis. Descriptive analysis indicated the UHT processing treatment significantly changed the sensory aroma profile of the pea protein beverage; however, no further changes were reported as a result of storage. Aroma recombination experiments in pea protein samples confirmed the sensory relevance of the identified compounds and indicated lipid oxidation and the Maillard were the reaction pathways responsible for the observed aroma changes during the UHT treatment.

Characterization of the key aroma compounds in Longjing tea using stir bar sorptive extraction (SBSE) combined with gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), odor activity value (OAV), and aroma recombination.

Longjing tea is the most famous premium green tea, and is regarded as the national tea in China, with its attractive aroma contributing as a prime factor for its general acceptability; however, its key aroma compounds are essentially unknown. In the present study, volatile compounds from Longjing tea were extracted and examined using stir bar sorptive extraction (SBSE) combined with gas chromatography-mass spectrometry (GC-MS). Data obtained from the present study revealed that 151 volatile compounds from 16 different chemical classes were identified by GC-MS analysis. Enols (8096µg/kg), alkanes (6744µg/kg), aldehydes (6442µg/kg), and esters (6161µg/kg) were the four major chemical classes and accounted for 54% of the total content of volatile compounds. Geraniol (6736µg/kg) was the most abundant volatile compound in Longjing tea, followed by hexanal (1876µg/kg) and β-ionone (1837µg/kg). Moreover, 14 volatile compounds were distinguished as the key aroma compounds of Longjing tea based on gas chromatography-olfactometry (GC-O) analysis, odor activity value (OAV) calculations, and a preliminary aroma recombination experiment, including 2-methyl butyraldehyde, dimethyl sulfoxide, heptanal, benzaldehyde, 1-octen-3-ol, (E, E)-2,4-heptadienal, benzeneacetaldehyde, linalool oxide I, (E, E)-3,5-octadien-2-one, linalool, nonanal, methyl salicylate, geraniol, and β-ionone. This is the first comprehensive report describing the aroma characterizations and the key aroma compounds in Longjing tea using SBSE/GC-MS. The findings from this study contribute to the scientific elucidation of the chemical basis for the aromatic qualities of Longjing tea.

Sensory-directed flavor analysis of off-flavor compounds in infant formula with deeply hydrolyzed milk protein and their possible sources

Off-flavor compounds in IF-DHMP were identified using sensory-directed analysis. In total, 56 types of aroma-active compounds were identified in the off-flavor (OF) samples, positive control (PC) samples, and accelerated oxidation (AO) samples. The Aroma Extraction Dilution Analysis (AEDA) results showed that methional, generated via Maillard reaction, was the most important component with the highest dilution factor in OF. The results of aroma recombination, omission and spiking experiment revealed that compounds such as pentanal, methional, (E)-2-nonenal, 3-methylbutanal, (E)-2-heptenal, nonanal, (E,E)-2,4-heptadienal, 1-penten-3-one, 1-octen-3-one, and (E,E)-2,4-nonadienal were the major sources of off-flavor in OF. We observed that the off-flavor in OF samples originated due to proteolysis, Maillard reaction, or lipid oxidation during processing rather than due to lipid oxidation during storage.

Key aroma compounds in Chinese fried food of youtiao

AbstractKey aroma compounds in Chinese popular fried food of youtiao were characterized by solvent assisted flavor evaporation combined with gas chromatography‐mass spectrometry (GC‐MS) and aroma extract dilution analysis of gas chromatography‐olfactometry (AEDA/GC‐O), quantitation, and aroma recombination and omission. Four samples of youtiao fried with sunflower oil, soybean oil, rapeseed oil, and palm oil, respectively, differing in fatty acid composition, were selected to be investigated. A total of thirty‐five odorants were identified, among which twenty‐two odorants were quantitated by aid of authentic chemicals and with correction of recovery coefficients. Differences in odorants composition and aroma profile were observed among the four samples of youtiao fried with different oils. However, it was demonstrated in common thirteen compounds; that is, 3‐hydroxy‐2‐butanone, 3‐methylbutanal, furfural, 3‐(methylthio)propanal, 2‐furfurylthiol, phenylacetaldehyde, 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone, 2‐ethyl‐3,5‐dimethylpyrazine, 3‐ethyl‐2,5‐dimethylpyrazine, (E,E)‐2,4‐decadienal, 1‐octen‐3‐ol, (E,Z)‐2,6‐nonadienal, and (E)‐2‐nonenal contributed significantly to youtiao aroma. The work can provide some guidance to maintain the preferred youtiao flavor when modifying its preparation technology for safety concerns.

Characterization of Qingke Liquor Aroma from Tibet.

Qingke liquor is a very famous Tibetan alcoholic beverage made from "Qingke", hull-less highland barley, which is exclusively grown in Qinghai-Tibetan Plateau with an average altitude of 4000 m. Qingke liquor made in such an area whose quality or characteristics is a result of its geographic environment, including natural and human culture. In this study, the aroma compounds in two Qingke liquors made from highland barley grown at different elevations (QKH, high elevation, and QKL, low elevation) were compared by aroma extract dilution analysis (AEDA), aroma intensity (Osme), odor activity values (OAVs, ratio of concentration to odor threshold), and aroma recombination. Results revealed ethyl acetate, ethyl 2-methyl propanoate, ethyl butanoate, ethyl 3-methyl butanoate, ethyl pentanoate, ethyl hexanoate, ethyl octanoate, 3-methylbutanal, 3-methyl-1-butanol, 1-octen-3-ol, β-damascenone, 2,3-butanedione (diacetyl), acetoin, and 2-methoxyphenol (OAV ≥ 10) as important aroma active compounds to Qingke liquors. However, QKH had higher OAVs for most of the compounds than that of QKL. An aroma recombination study confirmed the analysis of aroma-active compounds in Qingke liquor, whereas the aroma emission test demonstrated 3-methylbutanal as the key aroma compound for both Qingke liquors.

Flavoromics approach to identifying the key aroma compounds in traditional Chinese milk fan

To determine the key aroma compounds in Chinese milk fan cheese, samples from 6 of the most popular handmade milk fan workshops in Yunnan province of China were analyzed by gas chromatography-mass spectrometry (GC-MS), gas chromatography-olfactometry (GC-O), sensory evaluation, aroma recombination and omission experiments. Seventy-one aroma compounds were identified by GC-MS, and 31 odor-active compounds were detected by GC-O. The relationships between the 31 odor-active compounds and 10 sensory evaluation properties were explored by partial least squares discriminant analysis. The results identified 23 initial key aroma compounds, which were used to simulate the aroma profile of milk fan in aroma recombination experiments. Aroma omission experiments identified propanoic acid, butanoic acid, octanoic acid, octanal, nonanal, 2-nonanone, and ethyl hexanoate as the key aroma compounds. Propanoic acid and butanoic acid contributed to cheese and rancid aromas, octanal and nonanal to the fat aroma, octanoic acid and 2-nonanone to the cheese aroma, and ethyl hexanoate to the fruity aroma of milk fan.

Characterization of the Key Aroma Compounds in Marselan Wine by Gas Chromatography-Olfactometry, Quantitative Measurements, Aroma Recombination, and Omission Tests.

Key odorants of red wine made from the hybrid grapes of Marselan (Vitis vinifera L.) were isolated by solid-phase extraction (SPE) and explored by gas chromatography-olfactometry (GC-O) analysis. Application of aroma extract dilution analysis (AEDA) revealed 43 odor-active compounds, and 31 odorants among them were detected with flavor dilution (FD) factors ranging from 9 to 2187. Comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC × GC-TOF-MS) were exploited to quantitate the aroma-active compounds with FD ≥9. The identification indicated β-damascenone as having the highest FD factors, followed by eugenol, 2,3-butanedione, citronellol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, phenethyl acetate, guaiacol, and 2-methoxy-4-vinylphenol. A total of 21 compounds were found to have odor activity values (OAVs) >1.0. Aroma reconstitution validation experiments showed a good similarity of blackberry, green pepper, honey, raspberry, caramel, smoky, and cinnamon aroma attributes between the original Marselan wine and the reconstructed wine. In addition, omission tests were carried out to further determine the contribution of odorants to the overall aroma.

Characterization of key odorants causing the roasted and mud-like aromas in strong-aroma types of base Baijiu.

The roasted and mud-like aromas in Chinese strong-aroma types of base Baijiu (base SAB) and the interactions among the corresponding key compounds causing these two characteristic aromas were investigated. A total of 68 and 64 odorants were identified in the base and commercial SAB by comparative aroma extract dilution analysis. Furthermore, the complex matrix of Baijiu always pose a long-term challenge for quantitative accuracy and precision of target aroma compounds; thus, the odorants with flavor dilution (FD) ≥ 9 were further quantified by multiple quantitative techniques, including the direct injection combined with gas chromatography-flame ionization detector, the vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction (VSLLME) combined with GC-MS, and the derivatization method combined with VSLLME-GC-MS, and 37 and 26 odorants were shown to be important odorants as their OAVs ≥1. Among these components, 5 compounds, hexanoic acid, butyric acid, p-cresol, 3-methylindole, and 3-(methylthio)propanal showed higher OAVs in base than in commercial SAB, and based on aroma recombination and omission analysis, they were confirmed to be the key odorants responsible for the mud-like and roasted odors. The evaluation of the aforementioned five key odorants by the "addition" test showed that the roasted and mud-like aromas of base SAB were related, and the odors were mainly attributed to additive or masking effects among the compounds.

Comparison of the Aroma Profiles of Intermediate Wheatgrass and Wheat Bread Crusts.

The aroma profiles of bread crusts made from intermediate wheatgrass (Thinopyrum intermedium) and whole wheat (Triticum aestivum) flours were compared. Based on gas chromatography/mass spectrometry/olfactometry analysis, twenty-four odorants were identified and further quantified. The concentrations of seventeen compounds were significantly different between intermediate wheatgrass and whole wheat bread crusts, of which sixteen compounds were higher in the whole wheat sample. The aroma profiles of the bread samples were subsequently characterized using sensory descriptive analysis (DA) and indicated that the roasted attribute was perceived at a significantly higher intensity in the whole wheat sample due to a greater amount of Maillard reaction compounds. Alternatively, bran and green notes were perceived at higher intensities in the intermediate wheatgrass sample, however they were not attributed to the presence of specific compounds but rather to a change in the aroma composition. Aroma recombination DA of the whole wheat and intermediate wheatgrass aroma models was similar to the original aroma profiles of the bread samples, demonstrating the sensory relevance of the identified odorants.

Characterization of Key Aroma-Active Compounds in Black Garlic by Sensory-Directed Flavor Analysis.

Black garlic is a new garlic product produced through fermentation of fresh garlic and is very popular in Asia countries due to its health benefits. Its key aroma-active compounds were characterized by gas chromatography-olfactometry-mass spectrometry (GC-O-MS), gas chromatography-time-of-flight mass spectrometry (GC-TOFMS), and sensory evaluation. In total 52 aroma compounds were identified, and 15 of them with high flavor dilution (FD) factors based on aroma extract dilution analysis (AEDA) were selected and quantitated. Finally, 9 key aroma-active compounds, including acetic acid (sour), allyl methyl trisulfide (cooked garlic), Furaneol (caramel), diallyldisulfide (garlic), diallyltrisulfide (sulfur), (E,Z)-2,6-nonadien-1-ol (cucumber), 3-methylbutanoic acid (sweat), 5-heptyldihydro-2(3H)-furanone (apricot), and diallyl sulfide (garlic), were determined through aroma recombination and omission experiment. In addition to the sulfur-containing compounds, heterocyclic compounds were the major aroma contributors in black garlic. Sensory evaluation revealed that the flavor profile of black garlic mainly consisted of sulfur, sour, sweet, fresh, sauce, gasoline, and roasted odors.

Characterization of Key Aroma Compounds in Beijing Roasted Duck by Gas Chromatography-Olfactometry-Mass Spectrometry, Odor-Activity Values, and Aroma-Recombination Experiments.

The dominant aroma compounds in the breast skin and breast muscle of Beijing roasted duck were investigated by gas chromatography-olfactometry-mass spectrometry (GC-O-MS), odor-activity values, and aroma recombination. The results demonstrated that a total of 42 aroma compounds were identified in Beijing roasted duck, including aldehydes, ketones, alcohols, acids, phenols, sulfur-containing compounds, and nitrogen-containing compounds. Among the 42 aroma compounds, 18 were identified as important odorants with odor-activity values (OAVs) greater than 1. Aroma-recombination-omission experiments and sensory evaluation demonstrated that nine aroma compounds significantly contributed to the characteristic aroma of Beijing roasted duck. These nine key aroma compounds were 2-furfurylthiol, dimethyl trisulfide, hexanal, heptanal, octanal, nonanal, methional, 1-octen-3-ol, and ( E, E)-2,4-decadienal. Among these, 2-furfurylthiol (3620 ≤ OAV ≤ 31 606) and dimethyl trisulfide (2515 ≤ OAV ≤ 23 470) significantly contributed to the aroma of roasted duck ( p < 0.01). Sensory evaluation of the recombination model with the nine aroma compounds scored 4.5 out of 5 points. The major aroma profile of Beijing roasted duck included strong fatty, roasty, and meaty aromas. The key aroma compounds of Beijing roasted duck were concluded to be 2-furfurylthiol, dimethyl trisulfide, hexanal, heptanal, octanal, nonanal, methional, 1-octen-3-ol, and ( E, E)-2,4-decadienal.

Characterization of the key aroma compounds in white bread by aroma extract dilution analysis, quantitation, and sensory evaluation experiments

The aroma compounds in four brands of white bread were characterized by aroma extraction dilution analysis, quantitation, aroma recombination, and omission tests. A total of 54 aroma compounds were detected. Among them, methional had the highest flavor dilution (FD) factor of 729, followed by (E,E)‐2,4‐decadienal (FD = 243), furaneol (FD = 243), and δ‐decalactone (FD = 243). Thirty‐nine compounds (FD ≥ 9) were quantitated then analyzed by odor activity values (OAVs), 31 of which had OAVs ≥ 1. Four recombination models showed a similarity of 90.35% to the corresponding white bread samples. Omission tests confirmed that (E,E)‐2,4‐decadienal (OAV = 1,229), 4‐methyl‐5‐thiazoleethanol (OAV = 274), δ‐decalactone (OAV = 70), furaneol (OAV = 40), 2‐phenylethanol (OAV = 20), and methional (OAV = 12) were the key aroma compounds in white bread. Additionally, the alcohols and acids also significantly (p < 0.001) contributed to the sour, sweet, and flour‐like notes of white bread. PRACTICAL APPLICATIONS: In this work, the key aroma compounds of white bread were confirmed. The content of aromas was significantly different among four brands of white bread with different recipes and processing techniques. These results provide an important theoretical basis for the improvement of quality control and processing of white bread.

Aroma Investigation of Chios Mastic Gum (Pistacia lentiscus Variety Chia) Using Headspace Gas Chromatography Combined with Olfactory Detection and Chiral Analysis.

Chios mastic gum (Pistacia lentiscus var. Chia) exhibits intensely sourish, green, resinous, and woody odor notes with hints of citrus and pine. Despite its attractive flavor, no description of its aroma properties by molecular sensory techniques has been published thus far. A total of 25 odor-active compounds with flavor dilution (FD) factors of 1-512 were identified by gas chromatography-mass spectrometry-olfactometry (GC-MS-O) combined with headspace solid-phase microextraction (HS-SPME) and stir bar sorptive extraction (HS-SBSE). Quantitative analyses performed by multiple HS-SPME and calculation of odor activity values of 10 odorants with high FD factors revealed an essential role of several minor components (e.g., β-myrcene, limonene, β-linalool, and perillene) for the overall aroma of mastic gum, besides the dominating compound α-pinene. The indispensable contribution of the minor odorants to mastic gum was further confirmed by aroma recombination and omission tests. Varying enantiomeric excess values of the key odorants were observed by multidimensional GC-MS.

Aroma Compounds in Chicken Broths of Beijing Youji and Commercial Broilers.

The unique flavor of Beijing Youji (BJY) chicken broth compared with that of commercial broilers (CB) was investigated by solvent-assisted flavor evaporation combined with AEDA/GC-O (aroma extract dilution analysis of gas chromatography-olfactometry), quantitation, and aroma recombination. A total of 71 odorants with almost the same major odorants (≥10 ng/g broth) were found by GC-O in both BJY and CB broths. However, BJY broth had thirty-two more extra odorants than CB broth, indicating the rich fragrance of the former. Aroma recombination and omission experiments demonstrated that 21 versus 17 odorants (with OAV ≥ 1) contributed significantly to BJY and CB broth aromas, respectively. Those key odorants mainly included sulfur-containing compounds and aliphatic aldehydes, such as 2-methyl-3-furanthiol, 3-(methylthio)propanal, ( E, E)-2,4-decadienal, etc. Furthermore, composition analysis of the meat suggested that the better flavor, with rather more odorants, of BJY broth is probably due to higher contents of polyunsaturated fatty acids and water-soluble flavor precursor, including ribose, cysteine, thiamine, etc., present in the BJY meat.

Understanding wine sorption by oak wood: Modeling of wine uptake and characterization of volatile compounds retention

Cooperage wood is a porous material and beverages exchange compounds with it by penetrating into its pores. This work demonstrates the enrichment of wood with wine during ageing. Three oak varieties were cut into different sized chips and immersed in fortified wine and water. Wine and water uptake were measured along time and sorption was described based on a saturation empirical model. Maximum uptake varied among wood types and was independent of particle size, which affected only equilibrium time. Sorption of wine volatiles such as alcohols, esters and acids in wood was shown, which was also dependent on wood type and independent of particle size. Multivariate analysis demonstrated differences and similarities in depletion of wood extractives and sorption of wine volatiles depending on wood variety. Sorption shown in this work demonstrates wood as a vector for aroma recombination, when reused for ageing between different beverages.

Characterization and comparison of key aroma compounds in raw and dry porcini mushroom (Boletus edulis) by aroma extract dilution analysis, quantitation and aroma recombination experiments

A study was carried out to determine and compare the key aroma compounds in raw and dry porcini mushroom (Boletus edulis). The volatile fractions were prepared by solvent-assisted flavor evaporation (SAFE), and aroma extract dilution analysis (AEDA) combined with gas chromatography-mass spectrometry (GC–MS) was employed to identify the odorants. Selected aroma compounds were quantitated and odor activity values (OAVs) were calculated revealing OAVs ≥ 1 for 12 compounds in raw porcini, among which 1-octen-3-one showed the highest OAV. In addition to compounds with eight carbon atoms, 3-methylbutanal, (E,E)-2,4-decadienal and (E,E)-2,4-nonadienal were also responsible for the unique aroma profile. In dry mushroom OAVs ≥ 1 were obtained for 20 odorants. Among them, 3-(methylthio)propanal, 1-octen-3-one and pyrazines were determined as predominant odorants. Overall, drying increased complexity of volatile compounds, thus significantly changing the aroma profile of porcini, providing more desirable roasted and seasoning-like flavor and less grass-like and earthy notes.