Solvent-assisted Flavor Evaporation Method Research Articles

Unravelling the key aroma compounds in the characteristic fragrance of Dendrobium officinale flowers for potential industrial application

Dendrobium officinale Kimura et Migo, one of the most important orchids because of its medicinal and edible value, has a typical Dendrobium Sw. flora scent, which has great application potential and commercial value to be characterized. The aroma-active compounds originating from D. officinale fresh flowers (DFF) were investigated using a sensomics approach. A combined solid phase microextraction and solvent-assisted flavor evaporation method were used to accurately capture the overall aromatic profile. Exactly 34 odorants were detected and identified by aroma extract dilution analysis (AEDA) coupled with gas chromatography/olfactometry−mass spectrometry (GC/O−MS) in DFF, of which nine odorants had a flavor dilution (FD) factor ≥27. All 34 odorants were further quantified. The odor activity values (OAVs) were calculated with the highest value of 7444, in which 18 compounds were confirmed to be key odorants, including 1-octen-3-ol, hexanal, nonanal, phenylacetaldehyde, linalool, 4-oxoisophorone, theaspirane, methyl salicylate, etc. Among the studies above, 42 out of 78 volatiles and 14 out of 34 odorants were identified in DFF for the first time. Then, the aroma profile of the DFF was simulated successfully by aroma recombination experiments based on the quantitation results, and the omission test suggested that alcohols are the decisive type of compounds in the DFF key odorants. In addition, a progressive addition test showed that the aroma recombinate prepared with 18 reference key odorants was able to reconstruct the characteristic aroma of DFF. In comparison, the recombinate constituted by mixing all 34 reference odorants in the same concentrations as determined in the DDF sample could mimic the flower scent and closely match the sensory attributes of the original D. officinale fresh flower.

Comparative Evaluation of Key Aroma-Active Compounds in Sweet Osmanthus (Osmanthus fragrans Lour.) with Different Enzymatic Treatments

Sweet osmanthus (Osmanthus fragrans Lour.) (OF) is one of the ten most famous flowers in China for its unique and delicate fragrance. A combined solid-phase microextraction and solvent-assisted flavor evaporation method was used to accurately capture the overall aromatic profile and characterize the predominant odorants of fresh osmanthus with the help of gas chromatography (GC)-olfactometry and comprehensive two-dimensional GC-quadrupole time-of-flight mass spectrometry (GC × GC-QTOF-MS). Twenty-six volatiles were identified for the first time in OF. A total of 23 potent odorants, dominated by monoterpene oxides and C6 aliphatic aldehydes, were identified. The efficacy of pectinase, β-glucosidase, and their combination on the aroma enhancement of OF was evaluated by quantitation of the target aroma components using GC-triple quadrupole-MS. The total concentration of key aroma components increased in all three enzyme treatment groups, and the increase was more significant in two β-glucosidase-treated groups. Changes in odor activity values and odor spectrum values of key odorants indicated that the pectinase-treated sample had more prominent floral, green, and potato-like scents. In contrast, the β-glucosidase-treated sample had more dominant floral, woody, almond-like, and fruity notes but less green odor, which was confirmed by sensory evaluation. β-Glucosidase and pectinase complement one another very well, and together, promote a remarkable aroma enhancement in OF.

Fingerprint of aroma-active compounds and odor activity values in a traditional Moroccan fermented butter “Smen” using GC–MS–Olfactometry

Smen is a fermented Moroccan butter highly regarded for its unique flavor characteristics. For the first time, this study aimed to evaluate the suitability and complementary performance of purge-and-trap extraction (PTE) and solvent-assisted flavor evaporation (SAFE) extraction methods prior to gas chromatography–mass spectrometry–olfactometry (GC–MS–O) in order to characterize key compounds in Smen. According to the representativeness tests, both SAFE and PTE aromatic extracts gave satisfactory similarity and intensity scores and were representative aromatic extracts, being similar to the Smen reference odor. Thirty-four volatile compounds were identified in Smen including acids, alcohols, esters, and ketones. Aroma extract dilution analysis (AEDA) was applied to characterize potent odorants, and odor activity values (OAVs) were calculated to authenticate these compounds. Twenty-two and nineteen aroma-active compounds were revealed by SAFE and PTE methods, respectively, with flavor dilution (FD) factors ranging from 4 to 4096, and OAVs between 1 and 3359. Ethyl butanoate, ethyl lactate, ethyl hexanoate, butanoic acid, and hexanoic acid were the main potent odorants in Smen, producing fruity-rose, creamy-whey, overripe fruit, ripened cheese, and rancid buttery/soapy odors, respectively. Therefore, SAFE and PTE methods were not only representative, but also complementary for elucidating potent aroma compounds of Smen.

Comparison and analysis of tomato flavor compounds using different extraction methods

Aroma is an essential sensory characteristic of tomato fruit and it plays an important role in the classification and consumer acceptability of tomato products. In this study, five methods including stir bar sorptive extraction, purge and trap (P&T), solvent-assisted flavor evaporation (SAFE), solid-phase micro-extraction (SPME), dynamic headspace sampling (DHS) were used to extract the flavor compounds from tomato fruits. The performances of each method by gas chromatography–olfactometry–mass spectrometry were also compared. The results showed that DHS method was not suited for the flavor compounds extraction from tomato samples. A total of 85 flavor compounds were identified by the rest of four extraction methods, including aldehydes (24), alcohols (18), ketones (10), esters (8), phenols (11), olefins (4) and other compounds (10). Among the four extraction methods, SAFE and SPME methods had better extraction efficacy and 73 compounds which accounted for 87% of all flavor compounds were extracted by this two methods. Aroma extract dilution analysis and calculation of odor activity values indicated that hexanal, 3-hexenal, (E)-2-hexenal, 1-penten-3-one and guaiacol were active aroma compounds in tomato fruit.

Characterization and comparative evaluation of volatile, phenolic and antioxidant properties of pistachio (Pistacia vera L.) hull

Pistachio hull is a good source of natural phenolics and antioxidants. Thanks to these bioactive molecules, the use of pistachio hull as nutritional ingredients in foods has attracted the interest of the food industry. In this study, phenolic compounds, antioxidant capacity, total phenol content, and volatile compounds were measured in the hull of two cultivars of pistachio, Uzun and Ohadi. LC-ESI-MS/MS method was used for the phenolic compounds analysis; 11 compounds were identified and quantified in the samples in which the major phenolic compound was gallic acid. The aroma composition of the pistachio hulls was isolated by SAFE (solvent-assisted flavor evaporation) method with dichloromethane and analyzed by GC–MS. Aroma compounds, including terpenes, acids, alcohols, phenols, and benzenes, were identified in both types of hulls, numbering 22 in the Uzun variety and 20 in the Ohadi. A significant linear correlation was confirmed between total phenolic compounds and antioxidant activity of hull extracts.

Chemical Composition and Aroma Evaluation of Essential Oils from Skunk Cabbage (Symplocarpus foetidus).

Two sample preparation methods, namely hydrodistillation (HD) and solvent-assisted flavor evaporation (SAFE), have been used to investigate the essential oils of the aerial parts (leaves and stems) of Symplocarpus foetidus, a plant with a characteristic odor, by gas chromatography mass spectrometry (GC-MS). Characteristic aroma-active compounds in the oils were detected by GC-Olfactometry (GC-O) and aroma extract dilution analysis (AEDA). From the HD method, the main compounds in the oil were found to be p-vinyl-guaiacol (15.5%), 2-pentyl-furan (13.4%), and (Z)-ligustilide (9.5%). From the SAFE method, the main compounds were 2-butoxy-ethanol (49.6%), ethyl-pentanoate (4.5%), and mesitylene (4.0%). In HD oil, the most intense aroma-active compounds were 2-pentyl-furan (flavor dilution factor (FD) = 32, odor activity value (OAV) = 57), p-vinyl-guaiacol (FD = 16, OAV = 41), and dimethyl disulfide (FD = 16, OAV = 41). In SAFE oil, the main aroma-active compounds were 2-butoxy ethanol (FD = 32, OAV = 16), and 2-methoxy thiazole (FD = 32, OAV = 25).

Comparison of Agitake (Pleurotus eryngii var. ferulae) Volatile Components with Characteristic Odors Extracted by Hydrodistillation and Solvent-assisted Flavor Evaporation

The chemical composition of volatile oil from agitake (Pleurotus eryngii var. ferulae) was established for the first time using gas chromatography (GC) and GC-mass spectrometry. Sixty-seven and 24 components were extracted by hydrodistillation (HD) using diethyl ether (DE) and dichloromethane (DM), respectively; these components accounted for 80.3% and 91.8% of the total oil, respectively. Thirteen and 48 components of were extracted by the solvent-assisted flavor evaporation method (SAFE), using DE and DM, respectively, and identified; these components accounted for 83.5% and 82.0% of the total oil, respectively. Methylsuccinimide and 2,3,7-trimethyl-2-octene were the most characteristic components by SAFE using DM.Odor evaluation of the volatile oil from agitake was also carried out using GC-olfactometry (GC-O), aroma extraction dilution analysis (AEDA), and the odor activity value (OAV). Sixteen, 8, 5 and 9 aroma-active components were identified using HD (DE and DM) and SAFE (DE and DM), respectively. The main aroma-active components extracted using HD and SAFE were 1-octen-3-ol (mushroom-like) and phenylacetaldehyde (floral), respectively. This study proved that HD and SAFE can be used as complementary extraction techniques for the complete characterization of volatile oil from agitake.

Comparison of suitability of SPME, SAFE and SDE methods for isolation of flavor compounds from extruded potato snacks

The aim of this study was to compare the usefulness of three extraction methods: SPME (solid-phase microextraction), SAFE (solvent-assisted flavor evaporation) and SDE (simultaneous distillation and extraction) for isolation of flavor compounds from extruded potato snacks for their subsequent analysis using GCO/AEDA and GC/MS techniques. Results showed that the most suitable extraction method for GC–olfactometry (GC–O) was SAFE, by which it was possible to isolate all 25 potent odorants which contribute to overall flavor of potato snacks due to the application of high vacuum and low extraction temperature. Extraction using SDE method resulted in formation of 5 additional compounds: 2-furfurylthiol, 2,5-dimethyl-3-furanthiol, octanal, (E)-2-octenal and nonanal recognized as artifacts. On the other hand, sniffing extracts from SPME fiber did not reveal 7 important compounds such as: 1-octen-3-ol, 2-ethyl-3,5-dimethylpyrazine, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 5-methyl-2,3-diethylpyrazine, β-damascenone or an unknown with a flavor of fresh pepper. However, this extraction method was shown to be very precise (RSD 3–9%), sensitive (lowest LOD for 6 compounds) and suitable for analysis of low boiling compounds, co-eluting with solvent in SDE or SAFE extracts. Preferably both SPME and SAFE methods should be used for a full characterization of odor-active compounds in potato snacks.