• Journal of Korean Society for Atmospheric Environment
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• v.18 no.E3
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• pp.165-174
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• 2002

A dual -column biofilter system with two different composts was used to investigate the macro-kinetics of dim-ethyl disulfide (DMDS) degradation. The biofilter columns were filled with compost mixtures up to one meter, The gas How rate and DMDS concentration to the biofilters were varied to study their effect on the removal characteris-tics of DMDS. It was found that the biodegradation of DMDS was governed by zero-order reaction -limited macro-kinetics for inlet DMDS concentrations between 10 and 55 ppmv. The overall average zero-order kinetic coeffi-cient for DMDS removal by compost was 0.50 ($\pm$0.1) ppm/sec for both compost mixtures studied. Variations in individual kinetic coefficients were observed due to varying environmental conditions, such as pH and temperature. The kinetic coefficients determined are specific to the system discussed in this work. During high acidity conditions in the filter beds, methyl mercaptan (MM) was observed in the gas samples collected. Appearance of MM was pro-bably due to decreased microbial activity in the lower portions of the biofilter. Considering the neutral pH range required and the presence of methyl mercaptan, it is likely that the microorganisms present in the biofilters used in this research are similar to the T. thioparus (strain E6) species.

• Bulletin of the Korean Chemical Society
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• v.18 no.3
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• pp.274-280
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• 1997

The rates and stoichiometry of the reaction of gallane-trimethylamine with selected organic compounds containing representative functional groups were examined in tetrahydrofuran solution under standardized conditions (THF, 0 ℃). And its reducing characteristics were compared with those of aluminum hydride-triethylamine(AHTEA). The rate of hydrogen evolution from active hydrogen compounds varied considerably with the nature of the functional group and the structure of the hydrocarbon moiety. Alcohols, phenol, amines, thiols evolved hydrogen rapidly and quantitatively. Aldehydes and ketones were reduced moderately to the corresponding alcohols. Cinnamaldehyde was reduced to cinnamyl alcohol, which means that the conjugated double bond was not attacked by gallane-trimethylamine. Carboxylic acids, esters, and lactones were stable to the reagent under standard conditions. Acid chlorides also were rapidly reduced to the corresponding alcohols. Epoxides and halides were inert to the reagent. Caproamide and nitrile were stable to the reagent, whereas benzamide was rapidly reduced to benzylamine. Nitropropane, nitrobenzene and azoxybenzene were stable to the reagent, whereas azobenzene was reduced to 1,2-diphenylhydrazine. Oximes and pyridine N-oxide were reduced rapidly. Di-n-butyl disulfide and dimethyl sulfoxide were reduced only slowly, but diphenyl disulfide was reduced rapidly. Finally, sulfones and sulfonic acids were inert to the reagent under the reaction.

• Journal of the Korean Society of Food Culture
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• v.25 no.3
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• pp.324-333
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• 2010

Off-flavor in foods and in raw materials is quite concerning, as it could signify deeper-rooted problems. Methods of reduction of "off-flavors" in traditional food such as Cheonggukjan and Kimchi, and in raw materials of soybean paste were studied by means of a literature review. It was found that the major components of "off-flavor" were due to butyric acid, valeric acid, alkylpyrazines, ammonia, and sulfides for Cheonggukjang, and for Kimchi were sulfur containing components such as methyl allylsulfide, dimethyl disulfide, diallyl disulfide, methyl allyl trisulfide, methyl 2-propenyldisulfide, dipropenyldisulfide. There is a demand for a scientific and systematic approach in overcoming the "off-flavor" problem. Nutritional aspects and safety should be considered. Several methods have been attempted, such as masking, binding, improving cooking process, inhibiting rancidity, and controlling the growth of micro-organism. Methods of masking were the most frequently ones used for the reduction of "off-flavor", and in some cases, othertechniques were additionally applied. The masking method would be useful in the reduction of "off-flavor" in traditional Korean foods, i.e. Cheonggukjang, Kimchi, as well as in new product development.

• Food Science and Preservation
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• v.23 no.3
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• pp.369-377
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• 2016

This study was conducted to investigate the effects of superheated steam (SHS) on volatile compounds and the quality characteristics of onion. Onion samples were treated by SHS at various steam temperatures ($100{\sim}300^{\circ}C$) for 1 min. Thiosulfinates and pyruvic acid were reduced by SHS treatment. The absorbance values obtained for thiosulfinates, the odor-causing compounds in onions, treated by were 0.889, 0.085, 0.049, 0.049, and 0.045, while that of the untreated control sample was 1.587. The pyruvic acid contents of onions treated by SHS were 7.57, 5.85, 1.66, 0.47, and 0.26 mg/mL, while that of the untreated control sample was 8.00 mg/mL. Volatile compounds such as, dipropyl trisufide, 1,3-propanedithiol, methyl thiirane, methyl propyl trisulfide, diallyl disulfide, 1-(methylthio)-1-propene, 1,1-thiobis-1-propene, 1,1-sulfinyl bispropane, dimethyl tetrasulfide, methyl propenyl disulfide, dimethyl trisulfide, and diallyl disulfide were reduced by SHS treatment. The results showed that antioxidant activities in the of onion samples were improved by SHS treatment. The hardness and chewiness of onions treated by SHS were significantly lower than those of the untreated control onion sample. Sensory evaluation suggested that SHS could help lower off-flavors in and enhance the palatability of onions. These results suggest that the application of SHS treatment to onions can decrease their off-flavors, change their textural attributes, and promote their sensory properties.

• Natural Product Sciences
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• v.11 no.2
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• pp.67-74
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• 2005

The ethanolic extracts of the leaves and bulbs of Allium victorialis var. platyphyllum (Liliaceae) collected from Daegwallyoung (D) and Ullung Island (U) in Korea were obtained using three different extracting methods. The first extracts, DL-1 DB-1, UL-1 and UB-1, were obtained from leaves (L) and bulbs (B) dried at $90^{\circ}C$, respectively, and the second extracts, DL-2, DB-2, UL-2 and UB-2, were obtained by extracting the leaves and bulbs of fresh plant parts. The third extracts DL-3, DB-3, UL-3 and UB-3 were obtained by incubating leaves and bulbs at $36^{\circ}C$. The six extracts obtained from A. victorialis var. platyphyllum at Daegwanllyoung (cultivated site) were orally administered to examine for a possible antihepatotoxic effect in $CCl_4-induced$ rats. DL-1 exhibited the most pronounced effect. The extracts inhibited serum ALT, AST, SDH, ${\gamma}-GT$, ALP and LDH activities elevated by $CCl_4$ injection and attenuated decreased glutathione S-transferase, glutatione reductase and ${\gamma}-glutamylcysteine$ synthetase activities and a decreased hepatic glutathione. However, the extracts obtained from Ullung Is. (native site) were less active than the extracts from Daegwallyoung, suggesting that A. victorialis var. platyphyllum from the cultivated site is more useful for functional food than of native site. These results also suggest that the antihepatotoxic effect is due to a higher content of hepatic glutathione. Gas chromatography of the twelve extracts showed significantly different sulfides, disulfides or trisulfides contents belonging to volatile sulfur substances (VSS). Nine components were identified on the basis of their mass spectra, namely, dimethyl disulfide, dimethyl trisulfide, diallyl disulfide, dipropyl disulfide, allyl methyl sulfide, allyl methyl trisulfide, 2-vinyl-4H-1,3-dithiin, 3,4-dihydro-3-vinyl-1,2-dithiin, and allithiamine. Extract DL-1 had the highest VSS content. Dried plant materials contained larger amounts of the VSSs than other extracts, and the leaves contained larger amount than the bulbs. These results suggest that heat treatment increases the antiheaptotoxic ability of A. victorialis var. platyphyllum by increasing the proportion of VSSs.

• Applied Biological Chemistry
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• v.44 no.1
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• pp.12-19
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• 2001

The major volatiles from Allium species were found to be sulfide compounds and the ratio of sulfide to volatiles was 66.1% in garlic, 66.1% in scallion, 62.3% in green onion, 39.2% in onion, and 4.2% in chive. Trace of cyclooctasulfur was found to be present among the volatiles. The most oviposition of 17.2% occurred at diallyl sulfide and the least of 0.8% at acetylthiophene whereas the most oviposition of 43.3% occurred at ethyl alcohol if concentration was 100%. Among the organic solvents used for dilution, ethyl alcohol received the highest 52.5% of oviposition and ether the lowest of 5.9%. Furfuryl mercaptan which is also one of the volatiles, received 46.9% of oviposition. For oviposition site, D. antiqua preferred sulfides at near 1%, ethyl alcohol at high, and other volatiles at various concentrations. At 100% concentration, most volatiles except dimethyl disulfide and ethyl alcohol received less oviposition than the control which was watered sand with no volatiles added.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1549-1556
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• 1999

This study was conducted to investigate the effects of pre-treated sub-ingredients and deodorization materials on the smell intensity of Kimchi during fermentation.Among the various sub-ingredients of Kimchi, garlic, ginger and green onion have comparatively strong smell. The smell intensities of the sub-ingredients, which were pre-treated with various patented methods were examined using the sensory evaluation method and AromaScan. The results showed that the good methods to reduce the smell of sub-ingredients were hot air drying and soaking with heating treatment. The pH, titratable acidity and the number of microorganism of Kimchi prepared with pre-treated sub-ingredients were not different among samples during fermentation. The smell intensity of the Kimchi with pre-treated sub-ingredients was weaker than that of control until ten fermentation days, but the smell intensity after 10 days of fermentation was not different among samples. The addition of ${\alpha}-cyclodextrin\;and\;{\beta}-cyclodextrin$, which are known to have deodorization effect, at a level of 0.1% respectively, to Kimchi resulted in no difference in the pH, titratable acidity and smell intensity during fermentation at $10^{\circ}C$ compared to those of control Kimchi. However, the addition of deodorizer reduced sulfide classes such as methyl allyl sulfide, dimethyl disulfide, allyl sulfide, methyl propyl disulfide up to 50%.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.351-355
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• 2002

Volatile compounds of kimchi-flavored steak sauce were isolated using simultaneous steam distillation and solvent extraction methods and identified by matching mass spectrum and retention index (RI) with the reference data. Twenty-three compounds including five aldehydes, four alcohols, four acids, three sulfur-containing compounds, one ketone, and six others were identified, among which the most abundant compound was eugenol. Sulfides such as dimethyl dis- and trisulfides, and acids such as acetic and dodecanoic acids showed strong effects on the kimchi flavor. Aroma extract dilution analysis with three fold dilution factor shown in over the FD value 34 identified 2-butanal, 2-pentylfuran, methyl-2-propenyl disulfide, and 2-furanmethanol. Strong good aroma was detected in the RI range between 1030 and 1357, bad aroma in RI 1561, sweety aroma in RI 2057, clover aroma of eugenol in RI 2122, and rancid flavor in RI 2251.

• Journal of Integrative Natural Science
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• v.8 no.2
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• pp.128-134
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• 2015

This paper focuses on the applicability of a continuous monitoring method on trace sulfur compounds in the ambient air by TD and GC/PFPD. The target compounds for monitoring include H2S(hydrogen sulfide), Methyl mercaptan, Dimethyl Sulfide, and Dimethyl disulfide. The result of QA/QC on monitoring instruments satisfies all the standards of Odor Measurement and Analysis Method, showing that the reproductivity of the compounds by concentration is within 10%, linearity is above 0.98 of a correlation efficient, method detection limit is 0.16 ppb by MM standard, and recovery rate is over 70%. Monitoring was conducted for two years from March 2006 to February 2008. As a result of the monitoring, the average concentration of H2S was 0.08 ppb, with the maximum concentration at 16.15 ppb. The result indicates that it is reasonable to do continuous monitoring as there appears a spontaneous event of high concentration by the condition of the site during monitoring odor-causing substances. Therefore, it is suggested that the continuous monitoring method used in this paper is appropriate to identify the characteristics of sudden occurrence and concentration variations of sulfur compounds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.333-341
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• 1999

This study was conducted to investigate physicochemical and functional properties of turnip. The concentrations of antocyanin in the rind of root was 3.24mg%, which was about 3.5 times higher than those in the flesh. Among free amino acids in each part of turnip, glutamic acid showed the highest concentrations(132.5mg%) in the root followed by alanine(25.0mg%), valine (23.3mg%), and serine (20.7mg%). Contents of minerals in the root of turnip were 395.7mg% for potassium, 187mg% for calcium, 53.6mg% for phosphate, and 40.7mg% for magnesium. According to dynamic heasdspace analysis, dimethyl disulfide was the most abundant flavor components from the juice of fresh turnip and other volatile components such as dimethyl trisulfide, 1 hexanal, 2 methyl 1 butamine, and 1 penten 3 ol were also identified. From the blanched turnip, however, 3 isothiocyanato 1 propene and 4 isothiocyanato 1 butene were mainly detected. Fresh and blanched turnips were extracted with water or 70% acetone to investigate percent yield. The concentrations of total polyphenols in the extracts of fresh turnip were higher than those of blanched turnip. The nitrite scavenging effects of water and 70% acetone extracts from fresh or blanched turnip were decreased as pH was increased. Between two water extracts, the 30oC water extracts showed the higher values of electron donating ability than 95$^{\circ}C$ water extracts.