Identification of the key aroma compounds in flaxseed milk using stir bar sorptive extraction, aroma recombination, and omission tests

Flaxseed milk is a plant-based dairy alternative that is rich in nutrients. Due to the low concentration of odor compounds in flaxseed milk, it cannot be completely extracted. This poses significant challenges for analysis. Therefore, this study developed a method suitable for extracting volatile compounds from flaxseed milk and compared it with three other extraction methods. It was found that Stir Bar Sorptive Extraction had the best extraction performance, identifying 39 odorants. Flavor dilution factors ranged from 1 to 512, with higher values observed for esters. 13 key odor compounds were identified (odor activity value > 1) using the external standard method for quantification; these included four aldehydes, three pyrazines, two alcohols, two esters, and two other compounds. Pyrazine compounds exhibited the highest concentrations. Aroma recombination and omission experiments showed that nine key odorants contributed significantly to the flavor profile of flaxseed milk, imparting aroma of cucumber, green, mushroom, fruity, sweet, and coconut.

Effect of Dehulling Pretreatment on the Flavor of Sesame Paste

Gas chromatography-olfactory-mass spectrometry (GC-O-MS) combined with Aroma Extract Dilution Analysis (AEDA) were employed to characterize the key odor-active compounds in sesame paste (SP) and dehulled sesame paste (DSP). The AEDA results revealed the presence of 32 and 22 odor-active compounds in SP and DSP, respectively. Furthermore, 13 aroma compounds with FD ≥ 2, OAV ≥ 1, and VIP ≥ 1 were identified as key differential aroma compounds between SP and DSP. Specifically, compounds such as 3-methylbutyraldehyde (OAV = 100.70-442.57; fruity), 2-methylbutyraldehyde (OAV = 106.89-170.31; almond), m-xylene (FD = 16; salty pastry), and 2,5-dimethylpyrazine (FD = 8-16; roasted, salty pastry) played an important role in this differentiation. Additionally, the dehulling process led to increased fermented, sweet, green, and nutty aroma notes in DSP compared to the more pronounced burnt and roasted sesame aroma notes in SP. Our findings offer a theoretical foundation for the regulation of sesame paste aroma profiles.

Characterization of key aroma-active compounds in blue honeysuckle (Lonicera caerulea L.) berries by sensory-directed analysis

Blue honeysuckle (Lonicera caerulea L.) berries are nutritionally rich and unique in flavor. However, its aroma compounds have not been known well. In this study, the key aroma-active compounds in 8 different varieties of blue honeysuckle berries were studied by sensory-directed analysis. Sensory evaluation suggested that the aroma profile of blue honeysuckle berry was fruity, floral, grassy, sweet, and sour. A total of 68 aroma compounds were detected by two-dimensional comprehensive gas chromatography-olfactometry-mass spectrometry analysis (GC × GC-O-MS). Then, aroma extraction dilution analysis (AEDA) and odor activity value (OAV) showed that 12 compounds were indicated to be the major aroma contributors. According to the principal component analysis (PCA) results, eight varieties were divided into three categories for their differences on alcohols and terpenoids content. Finally, the aroma recombination and omission experiments determined that linalool, hexanal, eucalyptol, octanal, nonanal, and ethyl 2-methylbutyrate were the key aroma-active compounds in blue honeysuckle berries.

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.

Profiling of Aroma-Active Compounds in Ylang-Ylang Essential Oils by Aroma Extract Dilution Analysis (AEDA) and Chemometric Methods

The aroma-active compounds in the extra, first, and third grades of ylang-ylang essential oils (YYEO) from Comoros and Madagascar were identified by gas chromatography-mass spectrometry with olfactometry (GC-MS/O) using an aroma extract dilution analysis (AEDA) technique. In the previous study, the authors investigated differences in volatile compound profiles between YYEO of different grades and regions using GC coupled with a flame ionization detector (FID) and GC-MS. This study follows up with identification of the aroma-active compounds present in YYEO of various grades from both origins and to profile the aroma of those oils. For the first time, principal component analysis (PCA) on AEDA logarithmic flavor dilution (LFD) data was performed, in comparison with the corresponding PCA on GC-FID-MS data. Based on AEDA data, 21 aroma-active compounds were found across all samples and grades of YYEO, with 8 common ones previously identified by GC-FID. Linalool had the highest odor activity and is the major component of YYEO, followed by geraniol, although the latter only appeared as a much smaller peak in the chromatogram. Other trace compounds such as eugenol and vanillin were also found to be significant to the aroma of YYEO. Using PCA on resulting LFD data, YYEO from Comoros were found to have spicier odor qualities as compared to those from Madagascar. The main contributors that determine the difference in a spicy aroma profile of Comoros and Madagascar oils are vanillin, methyl eugenol, and trans-cinnamyl acetate.

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

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

Key Aroma Compounds in Roasted White Kołuda Goose

Aroma-active compounds in the roasted leg meat of White Kołuda goose were assayed by gas chromatography-olfactometry, using aroma extract dilution analysis and solvent-assisted flavor evaporation. Quantitation, recombination-omission tests, and sensory evaluation were carried out. Thirty aroma compounds, for which odor activity values (OAVs) were calculated and for which the flavor dilution factors were greater than or equal to 1, were identified. The concentration of aroma compounds ranged from 0.06 to 633 (μg/kg). The highest OAVs (>1024) were for 2-furfurylthiol, 2-acetyl-1-pyrroline, and 1-octen-3-one. Nine key aroma compounds were: 2-furfurylthiol, 2-acetyl-2-thiazoline, 1-octen-3-one, 2-phenylethanethiol, 4,5-dimethyl-3-hydroxy-2(5H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E,E)-2,4-decadienal, 2-acetyl-1-pyrroline, and 3-(methylthio)propanal. The intensity of the dominating roasted, meaty/broth, and fatty notes in the recombination model consisting of the key odorants were rated (10-point scale) at 4.6-5.8 points, relative to the original roasted goose (5.2-6.2). The aroma compounds defined predominantly the meaty, roasted, and fatty flavors during the descriptive sensory evaluation of the roasted goose meat.

Characterization of Aroma-Active Compounds in Northern Highbush Blueberries "Bluecrop" (Vaccinium corymbosum "Bluecrop") and "Elliott" (Vaccinium corymbosum "Elliott") by Gas Chromatography-Olfactometry Dilution Analysis and Odor Activity Value

Aroma-active compounds in northern highbush blueberries "Bluecrop" (Vaccinium corymbosum "Bluecrop") and "Elliott" (Vaccinium corymbosum "Elliott") were isolated using solvent extraction followed by solvent-assisted flavor evaporation. The aroma-active compounds were compared by aroma extract dilution analysis (AEDA) on a polar and a chiral column and odor activity values (OAVs). The results showed that both cultivars had similar aroma-active compounds, but the flavor dilution (FD) factors and OAV values varied, responsible for the subtle aroma differences. AEDA (FD ≥ 64) suggested that the important aroma-active compounds in both cultivars could be ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, (Z)-3-hexenal, 1-octen-3-one, (Z)-3-hexen-1-ol, methional, linalool, (E,Z)-2,6-nonadienal, 2-methylbutanoic acid, α-terpineol, (E,E)-2,4-nonadienal, β-damascenone, geraniol, geranyl acetone, o-cresol, eugenol, and vanillin. Different isomers can have different sensory thresholds and attributes. Enantiomer analysis revealed that although S-(+)-linalool was dominant in blueberry, R-(-)-linalool had a higher FD value and OAVs than that of the (S)-isomer. The S-(-)-α-terpineol was slightly elevated than R-(+)-α-terpineol in both cultivars.

Characterization of the Key Aroma-Active Compounds in Yongchuan Douchi (Fermented Soybean) by Application of the Sensomics Approach

Yongchuan douchi is a traditional fermented soya bean product which is popular in Chinese dishes due to its unique flavor. In this study, the key aroma-active compounds of Yongchuan douchi were characterized by the combined gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS) with sensory evaluation. In total, 49 aroma compounds were sniffed and identified, and 20 of them with high flavor dilution factors (FD) and odor activity values (OAVs) greater than one were screened by applied aroma extract dilution analysis (AEDA) and quantitated analysis. Finally, aroma recombination and omission experiments were performed and 10 aroma-active compounds were thought to have contributed significantly including 2,3-butanedione (butter, cheese), dimethyl trisulfide (garlic-like), acetic acid (pungent sour), acetylpyrazine (popcorn-like), 3-methylvaleric acid (sweaty), 4-methylvaleric acid (sweaty), 2-mehoxyphenol (smoky), maltol (caramel), γ-nonanolactone (coconut-like), eugenol (woody) and phenylacetic acid (flora). In addition, sensory evaluation showed that the flavor profile of Yongchuan douchi mainly consisted of sauce-like, sour, nutty, smoky, caramel and fruity notes.

Characterization of the Key Aroma Compounds in a Commercial Fino and a Commercial Pedro Ximénez Sherry Wine by Application of the Sensomics Approach

Following the sensomics approach, the key aroma compounds of a commercial Fino and Pedro Ximénez sherry were identified, quantitated, and validated through recombination experiments. In Fino sherry, 31 compounds were determined in concentrations above their odor detection thresholds, with the fruity/green smelling 1,1-diethoxyethane displaying the highest odor activity value ((OAV); the ratio of the concentration to the odor threshold) of 8970, followed by ethyl (2S,3S)-hydroxy-3-methylpentanoate (853) and 2- and 3-methylbutanal (448). In the Pedro Ximénez sherry, 23 compounds were present in concentrations exceeding their odor thresholds, and the malty smelling 2- and 3-methylbutanal were found with the highest OAV (1006), followed by 1,1-diethoxyethane (808) and methylpropanal (561). The results were compared to those characterized previously by us in an Amontillado sherry revealing that in all three sherry wines, 1,1-diethoxyethane, 2- and 3-methylbutanal, methylpropanal, ethanol, ethyl (2S,3S)-2-hydroxy-3-methylpentanoate, acetaldehyde, and 3-(methylthio)propanal, as well as the fruity-smelling ethyl 2-methylbutanoate, ethyl hexanoate, ethyl octanoate, and ethyl 3-methylbutanoate ranked among the 15 odorants with the highest OAVs. But, although most odorants were identical in the three sherries, their amounts differed significantly. The results are discussed considering the different winemaking processes and the different aroma profiles.

Characterization of Odor-Active Compounds of Ichang Lemon (Citrus wilsonii Tan.) and Identification of Its Genetic Interspecific Origin by DNA Genotyping

Ichang lemon is a citrus fruit whose rind gives off a delicious and much appreciated fragrance and flavor. The volatile components of the fruit peel of Ichang lemon were investigated by GC-MS and GC-O (AEDA method). Simultaneously, its genetic origin was identified by using diagnostic SNP markers specific to ancestral species and multiallelic SSR and InDel markers. Ichang lemon combines three ancestral genomes (Citrus maxima, Citrus ichangensis, and Citrus reticulata) and may be a pummelo × Yuzu hybrid. Although the major compounds of the Ichang lemon aromatic profile were present in Citrus junos, a few pummelo-specific compounds were also detected, such as indole and nootkatone, in agreement with its maternal lineage. 3-Methyl-3-sulfanylbutyl acetate, reported to occur in passion fruit and brewed coffee, was identified by GC-MS, GC-QTOF-MS, and GC-FTIR for the first time in citrus. This odor-active compound has a sulfurous, tropical fruity, green note.

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

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

Chemical Characterization of Two California-Grown Avocado Varieties (Persea americana Mill.) over the Harvest Season with an Emphasis on Sensory-Directed Flavor Analysis

The research objective was to characterize avocado's aroma-active volatiles and use information about its overall composition, such as lipid profile, to discuss likely biosynthetic origins. To achieve this, two varieties, "Hass" and "3-29-5" (GEM), were evaluated during their commercial harvest period for dry weight, moisture content (freeze-drying), oil content (Soxhlet extraction), fatty acid composition, and aroma profile. Solvent-assisted flavor evaporation and aroma extract dilution analysis were performed on aroma extracts. Oleic acid (>50%) was the prominent fatty acid in the oil of both varieties. The majority of the aroma-active compounds in avocado are lipid-derived. The most notable compounds are 1-octen-3-one (mushroom) with a flavor dilution factor as high as 8192, hexanal (grassy), (Z)-4-decenal, an unknown, and (E,E)-2,4-nonadienal. Over the mid-to-late harvest season, a decline in hexanal and an increase in octanal were observed. In contrast to "Hass", the hexanal content was relatively stable in "3-29-5".

Key aroma-active compounds in brown sugar and their influence on sweetness

Brown sugar (non-centrifugal cane sugar) is popular for its pleasant caramel-like aroma and sweetness. Vacuum simultaneous steam distillation and extraction (V-SDE) and gas chromatography-mass spectrometry (GC-MS) was used to study the volatile fraction of brown sugar. To further determine the aroma-active compounds in brown sugar, gas chromatography-mass spectrometry-olfactometry (GC-MS-O) were used in conjunction with aroma extraction dilution analysis (AEDA), odor activity values (OAVs), and sensory evaluation to analyze the effects of the key aroma-active compounds on sweetness. A total of 37 aroma-active compounds were obtained, mainly including ketones, pyrazines, alkanes, phenols and alcohols, which contributed caramel, sweet and fruity notes to brown sugar. Among them, furfural, benzeneacetaldehyde, 2,3-butanedione, β-damascenone, 2-methoxyphenol, dihydro-2-methyl-3(2H)-furanone, 2-furanmethanol and butyrolactone could significantly enhance the sweetness of sugar solution because of the congruency of the aroma attributes and sweetness.

Insights into the Role of 2-Methyl-3-furanthiol and 2-Furfurylthiol as Markers for the Differentiation of Chinese Light, Strong, and Soy Sauce Aroma Types of Baijiu

The sensory impacts of two thiols, 2-methyl-3-furanthiol (MFT) and 2-furfurylthiol (FFT), in Chinese soy sauce aroma-type Baijiu (SSB), strong aroma-type Baijiu (STB), and light aroma-type Baijiu (LTB) (liquor) were evaluated and combined with partial least squares discriminant analysis (PLS-DA) to differentiate Chinese Baijiu. The flavor dilution factors of these two thiols ranged from 81 to 6561, and quantitative results showed that MFT and FFT were significantly more abundant (p < 0.001) in SSB than in STB and LTB. The determined odor activity values (OAVs) suggest that MFT (OAV: 34-121) and FFT (OAV: 11-103) contribute significantly to the overall aroma profiles of LTB and STB. Interestingly, the OAVs of these two thiols were high (256-263) and did not significantly differ (p > 0.05) in SSB. Notably, hierarchical cluster analysis and PLS-DA results revealed that these compounds can be used to differentiate Chinese LTB, STB, and SSB. According to their prominent organoleptic and distinguishing roles, these two thiols can be regarded as flavor markers for SSB.

Evolution of the key odorants and aroma profiles in traditional Laowuzeng baijiu during its one-year ageing

Changes of key odorants and aroma profiles of Chinese Laowuzeng baijiu during its one-year ageing were determined by HS-SPME-AEDA and direct injection-AEDA (DI-AEDA). Ethyl hexanoate, (E,E)-2,4-decadienal, and 2-phenylethyl acetate showed the highest FD value (486) in all ageing stages. With regards to aroma profiles, fruity, floral, acidic, sweet/honey and cheesy aromas were enhanced during storage, while pickled vegetable, grain and alcoholic notes weakened during the ageing. Quantitation and OAVs showed that most of the aroma compounds (OAVs > 1), including ethyl esters, aldehydes, and acids, increased their contents within the same period, whereas nonanal, 2-phenylethyl acetate, ethyl benzoate, 4-ethylguaiacol, propanol and 3-methyl-1-butanol decreased in content after the storage of 365 days. Simulated aged samples, in which fresh samples were spiked with 18 compounds, were examined by triangle tests, which indicated that the "fruity" compounds were crucial for maintaining the special aroma profile of an aged sample.

Chemical Composition, Enantiomeric Distribution, and Sensory Evaluation of the Essential Oils Distilled from the Ecuadorian Species Myrcianthes myrsinoides (Kunth) Grifo and Myrcia mollis (Kunth) DC. (Myrtaceae)

The essential oils of Myrcianthes myrsinoides and Myrcia mollis, belonging to the Myrtaceae family, were obtained by steam distillation. They were analyzed by gas chromatography-mass spectrometry (GC-MS), gas chromatography-flame ionization detector (GC-FID), enantioselective gas chromatography, and gas chromatography-olfactometry (GC-O). A total of 58 compounds for Myrcianthes myrsinoides essential oil (EO) and 22 compounds for Myrcia mollis EO were identified and quantified by GC-MS with apolar and polar columns (including undetermined components). Major compounds (>5.0%) were limonene (5.3%–5.2%), 1,8-cineole (10.4%–11.6%), (Z)-caryophyllene (16.6%–16.8%), trans-calamenene (15.9%–14.6%), and spathulenol (6.2%–6.5%). The enantiomeric excess of eight chiral constituents was determined, being (+)-limonene and (+)-germacrene D enantiomerically pure. Eight components were identified as determinant in the aromatic profile: α-pinene, β-pinene, (+)-limonene, γ-terpinene, terpinolene, linalool, β-elemene and spathulenol. For M. mollis, the major compounds (>5.0%) were α-pinene (29.2%–27.7%), β-pinene (31.3%–30.0%), myrcene (5.0%–5.2%), 1,8-cineole (8.5%–8.7%), and linalool (7.7%–8.2%). The enantiomeric excess of five chiral constituents was determined, with (S)-α-pinene and (+)-germacrene D enantiomerically pure. The metabolites β-pinene, 1,8-cineole, γ-terpinene, terpinolene, linalool, and (E)-β-caryophyllene were mainly responsible for the aroma of the EO. Finally, the M. myrsinoides essential oil has an inhibitory activity for cholinesterase enzymes (IC₅₀ of 78.6 μg/mL and 18.4 μg/mL vs. acethylcholinesterase (AChE) and butyrylcholinesterase (BChE) respectively). This activity is of interest to treat Alzheimer’s disease.

Chemical, Enantioselective, and Sensory Analysis of a Cholinesterase Inhibitor Essential Oil from Coreopsis triloba S.F. Blake (Asteraceae)

The fresh leaves of Coreopsis triloba S.F. Blake, collected at Cerro Villonaco in Loja, Ecuador, were investigated with respect to their essential oil (EO). The chemical composition was determined qualitatively through gas chromatography coupled with mass spectrometry (GC-MS) and quantitatively by gas chromatography coupled with flame ionization (GC-FID), using relative response factors (RRF) based on the enthalpy of combustion. The essential oil contained between 92.5% and 93.4% of monoterpene hydrocarbons, with (E)-β-ocimene being the main component (35.2–35.9%), followed by β-phellandrene (24.6–25.0%), α-pinene (15.3–15.9%), myrcene (10.9–11.0%), sabinene (2.2–2.4%), (Z)-β-ocimene (1.5%), and germacrene D (1.2–1.3%). The enantiomeric distribution of α-pinene, β-pinene, limonene, and germacrene D was also determined. The main components responsible for the aroma were identified through aroma extract dilution analysis (AEDA), a gas chromatography-olfactometry (GC-O) based technique, being α-pinene, β-pinene (0.6%), terpinolene (0.1%), α-copaene (0.1–0.3%), β-phellandrene, and (E)-4,8-dimethyl-1,3,7-nonatriene (0.1–0.2%) the main olfactory constituents according to the decreasing factor of dilution (FD) order. The biological tests showed IC₅₀ inhibition values of 42.2 and 6.8 µg/mL for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), respectively.

GC-MS olfactometric characterization of odor active compounds in cooked red kidney beans (Phaseolus vulgaris)

Red kidney beans are a staple pulse crop well known for its unique flavor characterized by kidney bean like, smoky, sulfury and earthy aroma notes. However, nature of compounds responsible for the unique beany odor of the cooked pulse has not been established. Steam distillation extracts of red kidney beans were subjected to Gas-chromatography olfactometry (GC-O) techniques namely detection frequency and aroma extract dilution analysis (AEDA). GC-O results suggest that methional with flavor dilution (FD) factor 21 is responsible for imparting the characteristic odor of the cooked red kidney beans. Apart from this p-vinyl guaiacol (FD 13) was identified as most important contributor towards smoky odor note. Sulfury note was mainly contributed by diethyl sulfide (FD 10) while 2-ethyl-3-methyl pyrazine (FD 13) was identified to be responsible for earthy note in cooked red kidney beans. Contribution of these compounds in characteristic aroma of cooked red kidney beans is reported here for the first time.

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.

Improved detection of key odourants in Arabica coffee using gas chromatography-olfactometry in combination with low energy electron ionisation gas chromatography-quadrupole time-of-flight mass spectrometry

Four Arabica coffees (Brazil, Colombia, Ethiopia, and Guatemala) yield highly variant odours, attesting to the complexities of coffee aroma that command advanced analytical tools. In this study, their volatiles were extracted using solvent-assisted flavour evaporation (SAFE) and headspace solid-phase microextraction (HS-SPME). Due to matrix complexity, some trace odourants were detected in SAFE extracts by aroma extract dilution analysis (AEDA) but remained difficult to quantify by gas chromatography-mass spectrometry (GC-MS). This prompted the application of low energy electron ionisation (EI) coupled with GC-quadrupole time-of-flight (GC-QTOF). Optimal low EI GC-QTOF parameters (EI energy: 15 eV, acquisition rate: 3 Hz) were applied to achieve improved molecular ion signal intensity and reproducibility (relative standard deviation < 10%) across five compounds, which resulted in good linearity (R² ≥ 0.999) and lowered detection levels (e.g. 0.025 ± 0.005 ng/mL for 4-hydroxy-5-methyl-3(2H)-furanone). Therefore, this method potentially improves the measurement of trace odourants in complex matrices by increasing specificity and sensitivity.

Key odorants of a Moroccan fermented milk product "Lben" using aroma extract dilution analysis

Lben is one of the main dairy products in Morocco, which broadly plays a significant role in food industry due to its nutritional, taste, aroma and health features. Aroma is a main quality factor for this kind of fermented dairy products. In this study, aroma compounds were extracted by four different methods. According to the sensory analysis, solvent-assisted flavor evaporation exhibited the most representative and reproducible method of Lben matrices. In general, a total of 24 volatile compounds were found for the first time in Lben, including aldehyde, alcohols, acids, esters, and ketones. The Lben characteristic aroma was characterized by 15 odour-active compounds using the application of the aroma extract dilution analysis. On the basis of flavor dilution (FD) results, butanoic acid (FD = 1024, ripened cheese), acetoin (FD = 512, buttery-creamy), 2-heptanol (FD = 512, fatty) and hexanoic acid (FD = 512, cheesy-goat) were the most powerful key odorants in Lben.

Identification of Odor-Active Trace Compounds in Blooming Flower of Damask Rose ( Rosa damascena)

The flower scent of the damask rose ( Rosa damascena) was studied. Two ultratrace components exhibiting high flavor dilution factors were detected as odor-active compounds via aroma extract dilution analysis (AEDA). One of these had a woody note and was identified as rotundone using multidimensional gas chromatography-mass spectrometry-olfactometry (MD-GC-MS-O), while the other had a citrus note and was identified as 4-(4-methylpent-3-en-1-yl)-2(5 H)-furanone (MPF) by fractionation of a commercial rose absolute from R. damascena. To the best of our knowledge, this is the first study addressing the organoleptic importance of these two compounds in the rose scent. Sensory analysis was conducted to evaluate the effects of rotundone and MPF. Adding 50 μg/kg rotundone and 5 μg/kg MPF to the aroma reconstitute of R. damascena provided it with blooming and natural characteristics. Additionally, the existence of rotundone and MPF in five types of fragrant roses was investigated.

Characterization of the Major Odor-Active Compounds in Jackfruit Pulp

An aroma extract dilution analysis applied to the volatiles isolated from jackfruit ( Artocarpus heterophyllus Lam.) pulp by solvent extraction and solvent-assisted flavor evaporation resulted in the detection of 48 odorants with flavor dilution (FD) factors between 1 and ≥8192. Application of gas chromatography-olfactometry to static headspace samples revealed additional five highly volatile odorants. The structures of 44 out of the 53 detected odorants could be assigned. These 44 compounds were quantitated using stable isotopically substituted odorants as internal standards, and their odor activity values (OAVs) were calculated as the ratio of the natural concentrations in jackfruit pulp and the odor threshold values in water. High OAVs were in particular obtained for ethyl 3-methylbutanoate (74000), ethyl butanoate (1800), 3-methylbutanal (1500), and 2-methylpropanal (1400). An aroma model solution based on the natural concentrations of the 35 compounds for which OAVs > 1 had been calculated fully mimicked the characteristic jackfruit pulp aroma.

Investigations on the Impact of the Special Flavor Hop Variety Huell Melon on the Odor-Active Compounds in Late Hopped and Dry Hopped Beers

Bottom-fermented and top-fermented beers, both either late or dry hopped with Huell Melon hops, and respective reference beers without late or dry hopping were subjected to a comparative odorant screening by aroma extract dilution analyses. On the basis of differences in the FD factors, 14 odorants were identified as hop-derived. Among them were ethyl 2-methylpropanoate, methyl 2-methylbutanoate, ethyl 2-methylbutanoate, propyl 2-methylbutanoate, myrcene, linalool, and geraniol. Differences between late hopped, dry hopped, and reference beers were substantiated by quantitation. Results showed minimal transfer of myrcene from hops into beer. Moderate transfer was observed for propyl 2-methylbutanoate, geraniol, and linalool. Process-induced changes of ethyl 2-methylpropanoate, ethyl 2-methylbutanoate, and methyl 2-methylbutanoate were beyond a direct transfer from hops into beer, suggesting a formation from the corresponding hop-derived carboxylic acids by yeast. Spiking experiments revealed that linalool and propyl 2-methylbutanoate contributed particularly to the characteristic aroma of beers flavored with Huell Melon hops.

Characterization of Potent Aroma Compounds in Preserved Egg Yolk by Gas Chromatography-Olfactometry, Quantitative Measurements, and Odor Activity Value

To characterize potent odor-active compounds in preserved egg yolk (PEY), volatile compounds were isolated by headspace solid-phase microextraction and solvent-assisted flavor evaporation. Gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS) analyses identified a total of 53 odor-active compounds by comparing the odor characteristics, MS data, and retention indices with those of reference compounds. Twenty-seven odorants were detected in at least five isolates that were extracted and analyzed by the same method, and their flavor dilution (FD) factors, ranging from 1 to 2048, were measured by aroma extract dilution analysis (AEDA). To further determine their contribution to the overall aroma profile of PEY, 22 odorants with FD factors ≥16 and GC-MS responses were quantitated, and their odor activity values (OAVs) were calculated. According to the OAV results, 19 odorants with OAVs ≥ 1 are the potent odorants that greatly contribute to the characteristic aroma of PEY. Nine compounds were identified for the first time: (E,Z)-2,6-nonadienal, (E)-2-nonenal, 2-methylbutanal, dimethyl disulfide, trimethylamine, methional, dimethyl trisulfide, diisopropyl disulfide, and diethyl disulfide.

Identification of characteristic aroma compounds in raw and thermally processed African giant snail (Achatina fulica)

Background

Food flavor appreciation is one of the first signals along with food appearance and texture encountered by consumers during eating of food. Also, it is well known that flavor can strongly influence consumer’s acceptability judgment. The increase in the consumption of snail meat across the world calls for the need to research into the aroma compounds responsible for the distinctive aroma notes of processed snail meat.

Results

The odorants responsible for the unique aroma notes in thermally processed giant African snail meats were evaluated by means of aroma extract dilution analysis (AEDA), gas chromatography–olfactometry (GC–O) and odor activity values (OAVs) respectively. Results revealed significant differences in the aroma profiles of the raw and thermally processed snail meats. Whilst the aroma profile of the raw snail meat was dominated with the floral-like β-ionone and β-iso-methyl ionone, sweaty/cheesy-like butanoic acid, and the mushroom-like 1-octen-3-one, the boiled and fried samples were dominated with the thermally generated odorants like 2-methylpyrazine, 2,5-dimethylpyrazine, 2-acetylthiazole and 2-acetylpyridine.

Conclusion

Finally, results have shown that sotolon, 2-acetyl-1-pyrroline, 2-furanmethanethiol, 2-methylbutanal, 1-octen-3-one, octanal, furanone, 2-methoxyphenol, 2-acetylpyridine, 2-acetylthiazole, and 2-methylpyrazine contributed to the overall aroma of the thermally processed snail meat.

Key Aroma Compounds in Smoked Cooked Loin

Smoked cooked loin is one of the most popular meat products in Poland. In this study, key volatile compounds in this traditional Polish meat product were determined using gas chromatography-olfactometry and aroma extract dilution analysis (AEDA). In total, 27 odor-active volatile compounds were identified, with flavor dilution (FD) factors ranging from 4 to 1024, with the highest FD factors noted for 2-methoxyphenol, 2-methoxy-4-(prop-2-enyl)phenol, and 2-methoxy-4-( E)-(prop-1-en-1-yl)phenol. Results of the quantitative analyses based on determinations with stable isotope dilution assays (SIDAs) and standard addition (SA), followed by calculations of the odor activity value (OAV), enabled identifying 24 of the volatile compounds responsible for flavor development in the analyzed smoked cooked loin. The highest OAVs were obtained for 2-methoxyphenol, 2-methyl-3-furanthiol, 1-octen-3-one, and 2-methyl-3-(methyldithio)furan.

Odor-Active Compounds in the Special Flavor Hops Huell Melon and Polaris

The volatiles isolated from samples of the special flavor hop varieties, Huell Melon and Polaris, and from the aroma hop variety, Hallertau Tradition, by solvent extraction and solvent-assisted flavor evaporation (SAFE) were subjected to a comparative aroma extract dilution analysis (cAEDA), which resulted in 46 odor-active compounds in the flavor dilution (FD) factor range of 16 to 2048. On the basis of high FD factors, myrcene, (3R)-linalool, and 2- and 3-methylbutanoic acid were confirmed as important variety-independent hop odorants. (1R,4S)-Calamenene was identified for the first time as an odor-active compound in hops. Clear differences in the FD factors and their subsequent objectification by stable isotope dilution quantitation suggested that high concentrations of the esters ethyl 2-methylbutanoate, ethyl 2-methylpropanoate, and propyl 2-methylbutanoate cause the characteristic fruity, cantaloupe-like odor note in Huell Melon hops, whereas the fruity and minty odor notes in Polaris are associated with high amounts of 3-methylbutyl acetate and 1,8-cineole.

Characterization of the Potent Odorants Contributing to the Characteristic Aroma of Beijing Douzhi by Gas Chromatography-Olfactometry, Quantitative Analysis, and Odor Activity Value

Beijing douzhi (BD) is a traditional snack in Beijing, China, and it has been listed as a part of Beijing's intangible cultural heritage. The potent odorants that contribute to the characteristic aroma of BD were investigated by analyzing the isolates from solvent-assisted flavor evaporation (SAFE) and simultaneous distillation-extraction. Using aroma extract dilution analysis based on gas chromatography-mass spectrometry and gas chromatography-olfactometry, 31 aroma-active compounds with flavor dilution (FD) factors ranging from 1 to 2187 were identified by comparison of their odor characteristics, MS data, and retention indices with those of reference compounds. To further determine their contribution to the aroma of BD, the odorants isolated using SAFE with FD factors ≥9 were quantified, and their odor activity values (OAVs; ratio of concentration to the respective odor threshold in water) were calculated. Eleven compounds were found to have OAVs ≥ 1, which indicated they were the potent odorants that contributed substantially to the characteristic aroma of BD. Among the 11 odorants, (E,Z)-2,6-nonadienal, eugenol, methional, p-cresol, 1-octen-3-one, and 3-methylbutanoic acid were not previously identified in BD.

Odor-active constituents of Cedrus atlantica wood essential oil

The main odorant constituents of Cedrus atlantica essential oil were characterized by GC-Olfactometry (GC-O), using the Aroma Extract Dilution Analysis (AEDA) methodology with 12 panelists. The two most potent odor-active constituents were vestitenone and 4-acetyl-1-methylcyclohexene. The identification of the odorants was realized by a detailed fractionation of the essential oil by liquid-liquid basic extraction, distillation and column chromatography, followed by the GC-MS and GC-O analyses of some fractions, and the synthesis of some non-commercial reference constituents.

Comparative Evaluation of Key Aroma-Active Compounds in Raw and Cooked Red Mullet (Mullus barbatus) by Aroma Extract Dilution Analysis

Raw red mullet (Mullus barbatus) and its cooked samples, obtained from steam and oven cooking, were subjected to aroma and key odorant analysis for the first time using GC-MS-O. The extraction of the aroma compounds was carried out by the direct solvent extraction-solvent assisted flavor evaporation (DSE-SAFE) method. Principal component analysis (PCA) was used to determine the relations between cooking processes and fish aroma compounds. By applying the aroma extract dilution analysis (AEDA), 8 and 13 aroma-active compounds were detected in raw and cooked fish samples, respectively. The most prominent differences between raw and cooked fish samples were as follows: 3-hydroxybutan-2-one, 2,3-octadienone, (E,E)-2,4-heptadienal, linalool, γ-butyrolactone, 1-methylpyrrolidin-2-one, 2H-furan-5-one and pyrrolidin-2-one were only detected in cooked samples while hexanal and 2-phenoxyethanol in only raw fish samples. GC-MS-O results clearly indicated that cooking process results in the development of characteristics and pleasant aroma of red mullet samples due to the lipid oxidation. The most dominant aroma-active compound in the cooked fish samples was the 1-octen-3-ol which is responsible for the mushroom-like odor.

Characterization of key aroma-active compounds in lychee (Litchi chinensis Sonn.)

Volatile compounds in ‘Sweetheart’ lychee were examined using gas chromatography-olfactometry/mass spectrometry (GC-O/MS). Solvent assisted flavor evaporation (SAFE) technique was used to identify the aroma-active compounds in lychee. Further characterization of the most important odorants in ‘Sweetheart’ lychee was achieved using aroma extract dilution analysis (AEDA). Thirty-one key aroma-active odorants were identified in the flavor dilution (FD) factor range of 2–1024. Methional (cooked potato) and geraniol (sweet, floral) exhibited the highest FD factors of 1024 and 512, respectively, these were followed by furaneol (sweet, caramel), nerol (floral, sweet), dimethyl trisulfide (DMTS) (preserved vegetable, sulfury), linalool (floral), (E,Z)-2,6 nonadienal (cucumber) and nerolidol (metalic, sesame oil). Furthermore, the flavor profile of ‘Sweetheart’ lychee was described by sensory analysis. Floral, tropical fruit, peach/apricot and honey were scored with relatively high scores for each aroma attribute. The sweetness rating was the highest score among all the attributes.

Characterization of the Potent Odorants Contributing to the Characteristic Aroma of Matcha by Gas Chromatography-Olfactometry Techniques

The odorants contributing to the characteristic aroma of matcha were investigated by analysis of the headspace samples and the volatile fractions prepared by a combination of solvent extraction and the SAFE techniques using three matcha powders of different grades (high, medium, and low). Gas chromatography-olfactometry of the headspace samples (GCO-H) and aroma extract dilution analysis (AEDA) applied to the volatile fractions revealed 16 (FD factor ≥1) and 39 (FD factor ≥4³) odor-active peaks, respectively. Among them, 14 and 37 of the odorants, most of which were newly detected in matcha, were identified or tentatively identified by GC-MS and GC-O, respectively. By comparing the perceived odorants of three matcha powders, it was revealed that eight compounds with sweet, green, metallic, and floral notes showed high flavor dilution (FD) factors irrespective of the grades. In addition, some odorants were suggested to influence the characteristic aroma of each grade. Furthermore, trans-4,5-epoxy-(E)-2-decenal, one of the potent odorants of matcha, was revealed to exist as a racemic mixture in matcha. This result suggested that trans-4,5-epoxy-(E)-2-decenal is formed by a nonenzymatic reaction in matcha, different from that in black tea, and that the unique manufacturing process of matcha has a close connection with its formation.

Chemical Studies of Yellow Tamarillo (Solanum betaceum Cav.) Fruit Flavor by Using a Molecular Sensory Approach

The odor-active volatile compounds of yellow tamarillo fruit (S. betaceum Cav.) were identified and quantified by using a sensomics approach, combining a gentle volatile extraction (solvent-assisted flavor evaporation (SAFE)), gas chromatography-mass spectrometry (GC-MS), and sensory analyses (gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA)). The medium-term purpose of this work is to evaluate the change of odor-active volatiles during processing. Thus, (Z)-3-hexenal, hexanal, and ethyl butanoate were identified as key aroma compounds of yellow tamarillo. The C₆-aliphatic compounds, aliphatic esters, and terpenols were characterized as the volatiles responsible for the herbal-green, fruity, and fresh-mint odor notes of this variety, respectively. Additionally, one non-volatile compound contributing to the residual bitter taste of this fruit was isolated by a bioguided (taste sensory analyses) fractionation. The freeze-dried fruit was sequentially liquid-liquid partitioned with solvents of different polarity, and then the ethyl acetate fraction was submitted to size exclusion chromatography. Then, its structure was elucidated as rosmarinic acid, by using common spectroscopic methods (mass spectrometry (MS) and nuclear magnetic resonance (NMR)). The amount of rosmarinic acid was quantified as 46.17 ± 1.20 mg/100 g of dried fruit, by the external standard method. Its bitter taste threshold value was determined by using the 3AFC (alternative forced choice) method to be 37.00 ± 1.25 mg/L.

Aroma Stability of Lemon-Flavored Hard Iced Tea Assessed by Chirality and Aroma Extract Dilution Analysis

The aroma of fresh and aged lemon-flavored hard tea was investigated by aroma extract dilution analysis (AEDA), quantitative comparison, and two-dimensional chirality analysis. Aroma extract dilution analysis of fresh hard tea samples showed 3-methylbutanal, isoamyl alcohol, β-damascenone, β-ionone, 2-phenylethanol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, and vanillin could be the most important aroma contributors to the hard tea due to their high FD values. The analysis of the aged hard tea samples did not reveal new compound formation during storage; however, compared with fresh samples, the flavor dilution value changed substantially in the aged samples. Both AEDA and quantitative analysis demonstrated that β-damascenone increased substantially in aged samples, whereas terpene aldehydes decreased substantially after storage. In addition, the FD value of linalool decreased dramatically in aged samples. Two-dimensional GC-MS chirality analysis revealed the FD value decrease of linalool in aged samples was largely due to the transformation of (R)-linalool to (S)-linalool, which has a higher sensory threshold.

Characterization of the Key Odorants in Chinese Zhima Aroma-Type Baijiu by Gas Chromatography-Olfactometry, Quantitative Measurements, Aroma Recombination, and Omission Studies

Zhima aroma-type Baijiu with typical sesame aroma is particularly popular in northern China. To our knowledge, it is still uncertain which components are important to make contributions to its unique aroma, although a few pieces of research have reported many volatile compounds in this Baijiu. The aroma-active compounds from the Baijiu were researched in this paper. A total of 56 odorants were identified in Chinese Zhima aroma-type Baijiu by aroma extract dilution analysis (AEDA). Their odor activity values (OAVs) were determined by different quantitative measurements, and then 26 aroma compounds were further confirmed as important odorants due to their OAVs ≥ 1, and these had higher values, such as ethyl hexanoate (OAV 2691), 3-methylbutanal (2403), ethyl pentanoate (1019), and so on. The overall aroma of Zhima aroma-type Baijiu could be simulated by mixing of the 26 key odorants in their measured concentrations. The similarity of the overall aroma profiles between the recombination model and the commercial sample was judged to be 2.7 out of 3.0 points. Omission experiments further corroborated the importance of methional and ethyl hexanoate for the overall aroma of Chinese Zhima aroma-type Baijiu.

Odorant Screening and Quantitation of Thiols in Carmenere Red Wine by Gas Chromatography-Olfactometry and Stable Isotope Dilution Assays

The sensory impact of thiols in Vitis vinifera 'Carmenere' red wines was evaluated. For this purpose, aroma extract dilution analysis was applied to the thiols isolated from a Carmenere red wine by affinity chromatography with a mercurated agarose gel. Results revealed the presence of four odorants, identified as 2-furanylmethanethiol, 3-sulfanylhexyl acetate, 3-sulfanyl-1-hexanol, and 2-methyl-3-sulfanyl-1-butanol, with the latter being described here for the first time in Carmenere red wines. Quantitation of the four thiols in the Carmenere wine screened by aroma extract dilution analysis and in three additional Carmenere wines by stable isotope dilution assays resulted in concentrations above the respective orthonasal odor detection threshold values. Triangle tests applied to wine model solutions with and without the addition of the four thiols showed significant differences, thus suggesting that the compounds do have the potential to influence the overall aroma of red wine.

Aroma Potential in Early- and Late-Maturity Pinot noir Grapes Evaluated by Aroma Extract Dilution Analysis

Aroma potentials in early and late maturity Pinot noir grapes were investigated in two consecutive vintages. The grape samples were hydrolyzed under acidic conditions, and the released odorants were studied by aroma extract dilution analysis (AEDA). Forty-nine main odor-active compounds were detected in the AEDA. The odorants released with high flavor dilution values were 1-hexanal, β-damascenone, guaiacol, and vanillin, together with C6-aldehydes and -alcohols, 4-vinylguaiacol, 4-vinylphenol, and 1-octen-3-one. The concentrations of aroma-active compounds were further quantitated. Compared with early harvest grapes, late harvest grapes released more β-damascenone, vanillin, 4-vinylguaiacol, and 4-vinylphenol in both years according to both AEDA and quantitation results, suggesting they were important aroma compounds that contribute to the characteristic of matured Pinot noir grapes.

Chemical composition, aroma evaluation, and inhibitory activity towards acetylcholinesterase of essential oils from Gynura bicolor DC

The compositions of the essential oils obtained from leaves and stems of Gynura bicolor DC. were analyzed by GC-MS. One hundred eight components of these oils were identified. (E)-β-caryophyllene (31.42 %), α-pinene (17.11 %), and bicyclogermacrene (8.09 %) were found to be the main components of the leaf oil, while α-pinene (61.42 %), β-pinene (14.39 %), and myrcene (5.10 %) were the major constituents of the stem oil. We found 73 previously unidentified components in these oils from G. bicolor. The oils were also subjected to odor evaluation. Eleven and 12 aroma-active compounds were detected in the leaf and stem oils, respectively. The abilities of these oils to inhibit acetylcholinesterase (AChE) activity were determined. The sesquiterpenoids in the oils were found to inhibit AChE activity more strongly than the monoterpenoids in the oils did. It was suggested that the three main components in each essential oil act synergistically against AChE activity. These results show that the essential oils obtained from G. bicolor are a good dietary source of AChE activity inhibition.

Characterization of the key aroma compounds in a commercial Amontillado sherry wine by means of the sensomics approach

An aroma extract dilution analysis (AEDA) carried out on the volatile fraction isolated by extraction/solvent-assisted flavor evaporation (SAFE) distillation from a commercial Amontillado sherry wine revealed 37 odor-active compounds with flavor dilution (FD) factors in the range of 16-4096. Among them, 2-phenylethanol (flowery, honey-like) and ethyl methylpropanoate (fruity) showed the highest FD factors, followed by ethyl (2S,3S)-2-hydroxy-3-methylpentanoate (fruity) reported for the first time in sherry wine. A total of 36 aroma-active compounds located by AEDA were then quantitated by a stable isotope dilution assay, and their odor activity values (OAVs; ratio of concentration to odor threshold) were calculated. The highest OAV was displayed by 1,1-diethoxyethane (2475; fruity), followed by 2- and 3-methylbutanals (574; malty) and methylpropanal (369; malty). Aroma reconstitution experiments and a comparative aroma profile analysis revealed that the entire orthonasal aroma profile of the Amontillado sherry wine could be closely mimicked.

Characterization of key odorants in Chinese chixiang aroma-type liquor by gas chromatography-olfactometry, quantitative measurements, aroma recombination, and omission studies

Chixiang aroma-type liquor is extensively welcomed by consumers owing to its typical fatty aroma, particularly in southern China. To our knowledge, no comprehensive characterization of aroma and flavor from chixiang aroma-type liquor has been published. It is still a confused question which components are the most important in characterizing its unique aroma. A total of 56 odorants were identified in chixiang aroma-type liquor by aroma extract dilution analysis (AEDA), and in different quantitative measurements, 34 aroma compounds were further demonstrated as important odorants according to odor activity values (OAVs). Furthermore, this research suggested that the aroma of chixiang aroma-type finished liquor could be successfully reconstituted by mixing 34 aroma compounds in the concentrations measured. Omission experiments further confirmed (E)-2-nonenal as the key odorant and revealed the significance of (E)-2-octenal and 2-phenylethanol for the overall aroma of chixiang aroma-type liquor. 3-(Methylthio)-1-propanol (methionol), diethyl 1,7-heptanedioate (diethyl pimelate), diethyl 1,8-octanedioate (diethyl suberate), and diethyl 1,9-nonanedioate (diethyl azelate), identified as the characteristic aromas of chixiang aroma-type liquor in 1995, had no effects on aroma based on omission/addition experiments.

Characterization of key aroma compounds in distiller's grains from wheat as a basis for utilization in the food industry

The limited use of distiller's grains (DG) in the food industry depends occasionally on the characteristic odor of DG. For a better understanding of this typical odor, a sensory evaluation was performed first. The impressions seasoninglike, roasty/breadlike, and malty/caramellike were revealed as the most intensive odors. Furthermore, analysis of volatile flavor compounds was applied on dried DG from wheat. Isolation was performed by means of headspace solid-phase microextraction, solvent-assisted flavor evaporation (SAFE), and simultaneous distillation/extraction and identification with gas chromatography-olfactometry/mass spectrometry. As a result, 42 odor-active compounds could be identified in total. Among 24 of the 42 odor-active compounds obtained by SAFE, 3-hydroxy-4,5-dimethyl-2(5H)-furanone (seasoninglike) showed the highest flavor dilution (FD) factor, and 7 compounds (3-methylbutanioc acid, dimethyl trisulfide, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2-ethyl-3,5-dimethylpyrazine, 2-phenylethanol, 2,6-nonadienal, and 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone) with a FD factor ≥ 32 were identified as key aroma compounds in DG from wheat.

Characterization of the potent odorants contributing to the characteristic aroma of Chinese green tea infusions by aroma extract dilution analysis

The volatile fractions of three famous Chinese green tea cultivar infusions (Longjing, Maofeng, and Biluochun) were prepared by a combination of the adsorptive column method and the SAFE techniques. The aroma extract dilution analysis (AEDA) applied to the volatile fractions revealed 58 odor-active peaks with flavor dilution (FD) factors between 4(1) and 4(7). Forty-six of the odorants, which included six odorants that have not been reported in the literature in Chinese green tea (2-isopropyl-3-methoxypyrazine, 2-ethenyl-3,5-dimethylpyrazine, cis-4,5-epoxy-(E)-2-decenal, 4-ethylguaiacol, (E)-isoeugenol, and 3-phenylpropionic acid), were identified or tentatively identified by GC-MS and GC-O. Among the perceived odorants, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, coumarin, vanillin, geraniol, (E)-isoeugenol, and 2-methoxyphenol showed high FD factors in all of the cultivars, irrespective of the cultivar or harvesting season, suggesting that these seven odorants are essential for the aroma of Chinese green tea. On the other hand, the contents of the odorants, FD factors of which were uneven between the cultivars, were suggested to influence the characteristic aroma of each cultivar. In addition, the formation mechanism of (E)-isoeugenol, one of the odorants which have not been reported in the literature with a high FD factor common to all the cultivars, was investigated, and it was suggested that the (E)-isoeugenol content of the tea products has a close correlation with the manufacturing process of the tea leaves.

aromatica) revealed by Aroma Extract Dilution Analysis (AEDA)

Some local cultivars and wilds of Iwateyamanashi (Pyrus ussuriensis var. aromatica) that grows wild in Northern Tohoku, Japan have good aromatic fruit. Iwateyamanashi may be valuable germplasms as a donor of odor compounds in breeding of Japanese pear (Pyrus pyrifolia), because almost all Japanese pear cultivars have faint odor. Fruits odors from a local cultivar 'Sanenashi', a wild accession (i0830) in Iwateyamanashi, cultivars of 'Kosui' and 'La France' were characterized at first with comparative Aroma Extract Dilution Analysis (AEDA). Application of AEDA, based on Gas chromatography/Olfactometry analysis (GC/O), on the odor concentration prepared from 'Sanenashi' indicated the presence of 33 odor-active compounds including methyl and ethyl esters, aldehydes and alcohol. The eleven odor compounds from 16 accessions of Iwateyamanashi showed various combinations and wide range of odor concentrations by Principal Component Analysis (PCA). Especially 2 accessions of local cultivar 'Natsunashi' plotted in the highly ethyl ester group might be useful for Japanese pear breeding.