• Bulletin of the Korean Chemical Society
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• v.18 no.10
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• pp.1130-1132
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• 1997

• The Korean Journal of Food And Nutrition
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• v.30 no.4
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• pp.788-795
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• 2017

This research has attempted to investigate the volatile flavor compounds of onion products through acetic fermentation, and to create a natural beverage with beneficial biological properties which can also fulfill customer quality standards. Onion products (OAF (M): Onion extracts at five days of acetic fermentation, OAF (F): Onion extracts at ten days of acetic fermentation) were produced by acetic fermentation. Volatile flavor compounds from onion extracts, OAF (M) and OAF (F) were used by Mixxor liquid extractions and analyzed by GC/MSD. Compounds of 49, 75 and 69 were identified in onion extracts, OAF(M) and OAF(F) respectively. Among the major volatile flavor compounds classes, sulfur containing compounds (36.7%), acids (31.2%) and aldehydes (13.5%) in onion extracts were changed into acids (69.6%) and alcohols (24.6%) in OAF (M) and acids (80.6%) and alcohols (15.5%) in OAF (F). During acetic fermentation acetic acid, 1,3-butanediol (odorless) and 2,3-butanediol (onion flavor) increased remarkably, sulfur-containing compound such as 2,5-dimethylthiophene having anti-oxidant activities was detected by fermentation.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.225-230
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• 2013

A new heteropolyanion-based ionic ($[Hmim]_5PMo_{10}V_2O_{40}$) was synthesized by the reaction of molybdovanadophosphoric acid ($H_5PMo_{10}O_{40}$) with N-methylimidazole. [$[Hmim]_5PMo_{10}V_2O_{40}$ showed a high catalytic activity in the oxidative desulfurization of sulfur-containing compounds in 1-methylimidazolium tetrafluoroborate ($[Hmim]BF_4$) ionic liquid using 30% aqueous $H_2O_2$ as the oxidant. The catalytic system was of high activity, simplified workup and flexible recyclability. The catalytic oxidation reactivity of sulfur-containing compounds decreased in the order dibenzothiophene (DBT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT). The influences of various parameters including reaction time (t) and temperature (T), catalyst dosage, and oxidant to sulfur molar ratio n(O)/n(S) on the desulfurization of model oil were investigated in details. 99.1% of DBT conversion in the model oil was achieved at atmospheric pressure under the optimal conditions: n(O)/n(S) = 4:1, $60^{\circ}C$, 100 min and molar ratio of catalyst to sulfur of 0.062. The ionic liquid can be recycled six times without significant decrease in activity.

• Journal of Life Science
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• v.21 no.12
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• pp.1740-1745
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• 2011

Volatile flavor compounds of 3 commercial products of black onion extract (produced in Changnyeong, Muan and Jeungpyeong) purchased in the online/offline markets were analyzed. A total of 51 compounds were detected in samples by solid phase microextraction (SPME)/GC/MSD, consisting mainly of carbonyl compounds (15), sulfur-containing compounds (8), aromatic compounds (6), furans (6), nitrogen-containing compounds (3), alcohols (2), acids (2) and miscellaneous compounds (10). Among carbonyls, 4 compounds including 2-methylbutanal, 3-methylbutanal, nonanal and benzaldehyde were detected in all samples, while two sulfur containing compounds, dimethyl disulfide and dimethyl trisulfide, were detected in high amounts and considered to be key flavors in black onion extracts. Particularly, thiophenes and 3 sulfur containing compounds (methylpropyl disulfide, methyl-(Z)-propenyl disulfide and methyl-(E)-propenyl disulfide) were detected only in two products. With acetic acid, furfural and pyrazines that formed through Maillard reaction during black onion aging were detected in high amounts in all samples. This also contributed to characteristic flavors such as roasted, sweet, and sour, in the flavor of black onion extracts.

• Bulletin of the Korean Chemical Society
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• v.28 no.3
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• pp.421-426
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• 2007

A linking ligand containing sulfur donor atoms in the terminal thiophene rings, 1,2-bis(thiophen-2-ylmethylene) hydrazine (L), was prepared by Schiff-base condensation. Ligand L reacted with [PdCl2(NCPh)2] to produce a molecular Pd compound [PdL2Cl2] (1). On the other hand, it reacted with AgNO3 and AgClO4 to produce a 2-D network [AgL0.5(NO3)] (2) and a 1-D polymer [AgL]ClO4 (3), respectively, whose structures are based on secondary intermolecular forces such as H-bonding, van der Waals interaction, and π-π stacking. Polymer 2 exhibited photoluminescence at room temperature in the solid state.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.222-228
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• 1997

Toha-jeot, a traditional salt-fermented seafood in Korea, was purchased on the market in order to analyze the flavor compounds. Volatile flavor compounds in unfermented and fermented Toha-jeot were compared by vacuum simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry. A total of 104 volatile flavor compounds were detected in both samples. Of these, 66 were positively identified, composed of aldehydes(14), ketones(8), alcohols(30), terpenes(20), sulfur-containing compounds(10), aromatic compounds (6), esters(12) and miscellaneous compounds(8). Levels of several other compounds such as aldehydes, terpenes, sulfur-containing compounds and esters decreased with fermentation time, whereas alcohols, ketone and aromatic compounds increased. Particularly, levels of alcohols in fermented Toha-jeot was 21 times higher than those of unfermented one. Major volatile flavor compounds in both samples were composed of terpenes, sulfur-containing compounds, esters and ethanol.

• Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.403-408
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• 2014

Antarctic krill Euphausia superba is an excellent potential source of food protein. We used enzymatic hydrolysate of Antarctic krill and 10 other precursors to seek the optimum krill reaction flavor and apply to ramen sauce. Krill concentrate and powder were compared by sensory evaluation. The krill powder performed better preference, and was added to ramen sauce, which itself performed better than a commercial shrimp flavored sauce. In total, 47 and 39 volatile compounds were identified from krill concentrate and powder, respectively. Both products contained many aldehydes and sulfur-containing compounds. The whisky flavor of aldehydes lowered the shrimp flavor of the krill concentrate. Sulfur-containing compounds were found in krill powder, confirming the results from sensory evaluation.

• Journal of the Korean Society of Food Culture
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• v.21 no.3
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• pp.319-324
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• 2006

Volatile compounds in low-temperature and long-term fermented Baechu kimchi were extracted by high vacuum sublimation(HVS), and then analyzed by gas chromatography/mass spectrometry(GC-MS). A total of 62 compounds, including 7 sulfur-containing compounds, 8 terpenes, 5 esters, 8 acids, 15 alcohols, 2 nitrites, 2 ketones, 11 aliphatic hydrocarbons and 4 miscellaneous compounds, were found in low-temperature and long-term fermented Baechu kimchi. Among them, acetic acid and butanoic acid were quantitatively dominant. Aroma-active compounds were also determined by gas chromatography/olfactometry(GC-O) using aroma extract dilution analysis(AEDA). A total of 16 aroma-active compounds were detected by GC-O. Butanoic acid was the most potent aroma-active compound with the highest FD factor($Log_3FD$) followed by linalool, acetic acid, 2-vinyl-4H-1,3-dithin and 3-methyl-1-butanol. The major aroma-active compounds, such as acetic acid and butanoic acid, were related to sour and rancid or notes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.441-446
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• 2006

Volatile flavor compounds in meat of the blue crab Portunus trituberculatus were compared using vacuum simultaneous steam distillation-solvent extraction (V-SDE) and solid phase microextraction (SPME)/ gas chromatography (GC)/ mass selective detection (MSD) methods. A total of 100 volatile flavor compounds were identified by both methods: 77 by V-SDE and 59 by SPME. These compounds were composed of 17 aldehydes, 12 ketones, 19 alcohols, 5 esters, 4 sulfur-containing compounds, 6 nitrogen-containing compounds, 23 aromatic compounds, 6 hydrocarbons, 2 terpenes, and 6 miscellaneous compounds. Although more compounds were detected using V-SDE than using SPME, the levels of all groups detected, except esters, were higher using SPME than using V-SDE. In addition to trimethylamine, aldehydes, and aromatic compounds, the S- and N-containing compounds with low thresholds are thought to have positive roles for flavors in the meat of the blue crab.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.33-40
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• 2003

Fusobacterium nucleatum, one of the bacteria causing halitosis, produces the volatile sulfur compounds (VSC) such as $H_2S$ in the media containing sulfur components, and forms FeS by binding with iron component. The various factors of oral cavity affect the concentration of sulfur compounds produced by Fusobacterium nucleatum. In this study, the effect of nutrients and pH on the production of sulfur compounds by Fusobacterium nucleatum was studied with the following results. 1. The optical density of broth was increased to $0.817{\pm}0.032$ and $1.297{\pm}0.024$ by adding 1.0% sodium thiosulfate and 0.05% L-cysteine hydrochloride in the media, respectively. 2. Though the optical density of broth was $0.799{\pm}0.032$ by adding volatile sulfur compounds (VSC) only in the media, it was increased to $1.775{\pm}0.003$ and $1.648{\pm}0.022$ by adding xylitol combined with glucose and fructose, respectively. 3. The concentration of VSC was above 20,000 ppb in the media above pH 5.5. The optical density of broth was still high in the media with L-cysteine hydrochloride of higher concentration, being low in the media of lower pH. 4. The concentration of VSC was high when there was distilled water or saline solution on the media, and their amount was small. These results suggest that the production of sulfur compounds by Fusobacterium nucleatum was inhibited by xylitol and acid.