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The chemical composition of essential oil extracted from Uncaria Hook ("Chotoko" in Japanese), the branch with curved hook of the herbal medicine Uncaria rhynchophylla has been investigated by GC and GC-MS analyses. Eighty-four compounds, representing 90.8% of the total content was identified in oil obtained from Uncaria Hook. The main components i were (E)-cinnamaldehyde (13.4%), α-copaene (8.0%), methyl eugenol (6.8%), δ-cadinene (5.3%), and curcumene (3.6%). The important key aroma-active compounds in the oil were detected by gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA), using the flavor dilution (FD) factor to express the odor potency of each compounds. Furthermore, the odor activity value (OAV) has been used as a measure of the relative contribution of each compound to the aroma of the Uncaria Hook oil. The GC-O and AEDA results showed that α-copaene (FD = 4, OAV = 4376), (E)-linalool oxide (FD = 64, OAV = 9.1), and methyl eugenol (FD = 64, OAV = 29) contributed to the woody and spicy odor of Uncaria Hook oil, whereas furfural (FD = 8, OAV = 4808) contributed to its sweet odor. These results warrant further investigations of the application of essential oil from Uncaria Hook in the phytochemical and medicinal fields.

Volatile oils obtained from both the liquid medium after incubation (MAI) and liquid medium before incubation (MBI) during the cultivation process of Lactobacillus brevis were isolated by hydrodistillation (HD) and analyzed to determine the utility of the liquid waste. The composition of the volatile oils was analyzed by capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). In total, 55 and 36 compounds were detected in the volatile oils from MAI (MAI oil) and MBI (MBI oil), respectively. The principle components of MAI oil were N-containing compounds, including 2,3-dimethylpyrazine (16, 37.1 %), methylpyrazine (4, 17.1 %). The important aroma-active compounds in the oils were detected by GC-Olfactometry (GC-O), and their intensity of aroma were measured by aroma extract dilution analysis (AEDA). Expressly, pyrazine compounds were determined as key aroma components; in particular, 2,5-dimethylpyrazine and 2,3-dimethylpyrazine were the most primary aroma-active compound in MAI oil. These results imply that the waste medium after incubation of L. brevis may be utilized as a source of volatile oils.

Enterococcus faecalis is one of the major lactic acid bacterium (LAB) species colonizing the intestines of animals and humans. The characteristic odor of the volatile oils obtained from both the liquid medium after incubation (MAI) and liquid medium before incubation (MBI) in the cultivation process of E. faecalis was investigated to determine the utility of the liquid medium. In total, fifty-six and thirty-two compounds were detected in the volatile oils from the MAI (MAI oil) and MBI (MBI oil), respectively. The principle components of MAI oil were 2,5-dimethylpyrazine (19.3%), phenylacetaldehyde (19.3%), and phenylethyl alcohol (9.3%). The aroma extract dilution analysis (AEDA) method was performed using gas chromatography-olfactometry (GC-O). The total number of aroma-active compounds identified in the volatile oil from MBI and MAI was thirteen compounds; in particular, 5-methyl-2-furanmethanol, phenylacetaldehyde, and phenylethyl alcohol were the most primary aroma-active compounds in MAI oil. These results imply that the industrial cultivation medium after incubation of E. faecalis may be utilized as a source of volatile oils.

Ranunculus nipponicus var. submersus is an aquatic macrophyte; it is known as a wild edible plant in Japan for a long time. In this study, the essential oils from the fresh and dried aerial parts of R. nipponicus var. submersus were extracted by hydrodistillation and analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Moreover, important aroma-active compounds were also detected in the oil using GC-olfactometry (GC-O) and aroma extract dilution analysis (AEDA). Thus, 98 compounds (accounting for 93.86%) of the oil were identified. The major compounds in fresh plant oil were phytol (41.94%), heptadecane (5.92%), and geranyl propionate (5.76%), while those of. Dried plant oil were β-ionone (23.54%), 2-hexenal (8.75%), and dihydrobovolide (4.81%). The fresh and dried oils had the green-floral and citrus-floral odor, respectively. The GC-O and AEDA results show that phenylacetaldehyde (green, floral odor, FD-factor = 8) and β-ionone (violet-floral odor, FD-factor = 8) were the most characteristic odor compounds of the fresh oils. β-Cyclocitral (citrus odor, FD-factor = 64) and β-ionone (violet-floral odor, FD-factor = 64) were the most characteristic odor compounds of the dried oil. These compounds are thought to contribute to the flavor of R. nipponicus var. submersus.

The chemical compositions of essential oils from the flower and aerial parts (i.e., leaf and branch) of Eurya japonica were determined and quantified using gas chromatography-mass spectrometry (GC-MS). A total of 87 and 50 compounds were detected in the oils from the flower and aerial parts, respectively. The main compounds of the flower oil were linalool (14.0%), (9Z)-tricosene (12.0%), and nonanal (7.4%). In the oil from the aerial parts, linalool (37.7%), α-terpineol (13.5%), and geraniol (9.6%) were detected. In the oils from the flower and aerial parts, 13 and 8 aroma-active compounds were identified by GC-olfactometry (GC-O) analysis, respectively. The key aroma-active compounds of the flower oil were heptanal [fatty, green, flavor dilution (FD) = 128, odor activity value (OAV) = 346], nonanal (sweet, citrus, FD = 128, OAV = 491), and eugenol (sweet, spicy, FD = 64, OAV = 62): in the oil from the aerial parts, the key aroma-active compounds were linalool (sweet, citrus, FD = 64, OAV = 95), (E)-β-damascenone (sweet, FD = 256, OAV = 4000), and (E)-β-ionone (floral, violet, FD = 128, OAV = 120). This study revealed that nonanal and eugenol impart the sweet, citrus, and spicy odor of the flower oil, while (E)-β-damascenone and (E)-β-ionone contribute the floral and sweet odor of the oil from the aerial parts.

Volatile oils obtained from both the liquid medium after incubation (MAI) and liquid medium before incubation (MBI) in the cultivation process of Lactobacillus acidophilus were isolated by hydrodistillation (HD) and analyzed to investigate the utility of the liquid waste. The composition of the volatile oils was analyzed by capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). In total, 46 and 19 compounds were detected in the volatile oils from MAI (MAI oil) and MBI (MBI oil), respectively. The principle components of MAI oil were fatty acids, including pentanoic acid (12.75%), heptanoic acid (14.05%), and nonanoic acid (14.04%). The important aroma-active compounds in the oils were detected by GC-MS/Olfactometry (GC-O), and their intensity of aroma were measured by aroma extraction dilution analysis (AEDA). Pyrazines were determined as key aroma components; in particular, 2-ethyl-5-methylpyrazine was the most primary aroma-active compound in MAI oil. In addition, as the characteristic aroma-active compounds, 3-(methylthio)-propanal, trimethylpyrazine, and pentanoic acid were also detected in MAI oil. These results imply that the waste medium after incubation of L. acidophilus may be utilized as a source of volatile oils.

The chemical composition of volatile oil obtained from aerial parts of Pavonia odorata were investigated using gas chromatography-mass spectrometry (GC-MS). Its aroma-active compounds were identified using gas chromatography-olfactometry (GC-O) and aroma extraction dilution analysis (AEDA). In order to determine the relative contribution of each compound to the aroma of P. odorata, relative flavour activity (RFA) was calculated. The hydrodistillation of P. odorata afforded yellowish oil and the yield was 0.009% (w/w) with a spicy, sweet, and green odour. Eighty-five compounds were identified in the oil by GC-MS; the major constituents of the volatile oil were ageratochromene (11.95%), palmitic acid (9.95%), hexahydrofarnesyl acetone (5.96%), β-eudesmol (4.53%) and β-caryophyllene oxide (3.08%). The most characteristic aroma compounds in the volatile oil were identified for β-caryophyllene oxide (FD-factor = 128, spicy), (E)-pinocarveol (FD-factor = 64, sweet), 3-butylpyridine (FD-factor = 64, spicy), and 2-nonanone (FD-factor = 32, green) by GC-MS, GC-O and AEDA. It seems that these compounds are responsible for the spicy, sweet and green odour of the aerial parts of P. odorata. The antioxidant activity of the volatile oil was also investigated by the oxygen radical absorbance capacity (ORAC) assay using fluorescein (FL) as the fluorescent probe. The ORAC value of the oil was 594.2 ± 25.9 μM TE/g. The results indicated that the volatile oil from the aerial parts of P. odorata could be considered as a natural antioxidant effect agent.

This study is focused on the volatile oils from the fruiting bodies of Pleurotus salmoneostramineus (PS) and P. sajor-caju (PSC), which was extracted by hydrodistillation (HD) and solvent-assisted flavor evaporation (SAFE) methods. The oils are analyzed by gas chromatography-mass spectrometry (GC-MS), GC-olfactometry (GC-O), and aroma extract dilution analysis (AEDA). A total of 31, 31, 45, and 15 components were identified in PS (HD and SAFE) and PSC (HD and SAFE), representing about 80.3%, 92.2%, 88.9%, and 83.0% of the oils, respectively. Regarding the aroma-active components, 13, 12, 13, and 5 components were identified in PS (HD and SAFE) and PSC (HD and SAFE), respectively, by the GC-O analyses. The results of the sniffing test, odor activity value (OAV) and flavor dilution (FD) factor indicate that 1-octen-3-ol and 3-octanone are the main aroma-active components of PS oils. On the other hands, methional and 1-octen-3-ol were estimated as the main aroma-active components of PSC oils.