• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.13-25
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• 2007

The water treatment plants in Seoul Metropolitan Area, which are under Korea Water Resources Corporation(KOWACO)'s management, take water from Paldang Reservoir in Han River System for drinking water supply. There are taste and odor (T&O) problems in the finished water because the conventional treatment processes do not effectively remove the T&O compounds. As part of countermeasures for taste and odor control, KOWACO is planning to introduce advanced water treatment process such as ozone and GAC in near future. This study evaluated the removal characteristics of T&O and dissolved organic matter (DOM) to find design and operation parameters of advanced water treatment processes in a pilot-scale treatment plant. The GAC adsorption capacity for DOC in the two GAC system (GAC and $O_3$-GAC) at an EBCT of 14min was mostly exhausted after 9months. The differency of the removal efficiency of DOC between $O_3$-GAC and GAC increased with increasing operation time because the bioactivity in $O_3$-GAC process was enhanced by post-ozone process. Removal by conventional treatment was unable to reach the target TON(threshold odor number) of 3 but GAC systems at an EBCT(empty bed contact time) of 14 min were able to archive the target with few exception. During the high T&O episodes, PAC as a pretreatment together with GAC could be useful option for T&O control. However, substantial TON removal continued for more than two year (> 90,000 bed volumes). At the spiking of less concentration 26 to 61 ng/L in the influent of GAC systems, GAC absorber and $O_3$-GAC processes could meet the treatment target. The better spike control after 12 and 19 months of operation compared to that after 7 months of operation is a strong indication of biological control. The results presented in this study had shown that $O_3$-GAC process was found to be more effective for T&O control than GAC process. And the main removal mechanism in GAC systems were adsorption capacity and biodegradation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.475-483
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• 2017

Geosmin and 2-methylisoborneol (2-MIB) produced by cyanobacteria during algal blooming in surface water are the major taste-and-odor-causing compounds in drinking water and need to be removed. Activated carbon is often used in treatment plants for the mitigation of odor problem. However, there is a lack of information on the effect of pore size distribution and particle size of activated carbon for adsorption of both odor compounds. Therefore, we studied the effect of pore size distribution and particle size of activated carbon on the adsorption of geosmin and 2-MIB. When comparing the adsorption of geosmin and 2-MIB between activated carbon fiber (ACF), powdered activated carbon (PAC) and granular activated carbon (GAC), the order of removal efficiency was PAC > ACF > GAC. As a result of comparing PACs with various pore distribution characteristics, well-developed micropores on activated carbon were found to be favorable for adsorption of geosmin and 2-MIB. For particle size, smaller was more effective for adsorption of geosmin and 2-MIB.

• The Korean Journal of Food And Nutrition
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• v.30 no.5
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• pp.973-982
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• 2017

Gastrodia elata Blume often has been used for the treatment of headaches, convulsions, hypertension, and neurodegenerative diseases. The main active constituents are gastrodin, 4-hydroxybenzyl alcohol, vanillyl alcohol, 4-hydroxybenzylaldehyde and parishin A, B, C and E. Because Gastrodia elata has also unacceptable off-odor (swine barnyard-like) for food, there is a need to reduce it as well as allow for greater utilization as a functional food materials. In this study, a major off-odor producing substance of Gastrodia elata was fractionated by steam distillation and silica gel column chromatography. The substance was identified as p-cresol(4-methyl phenol) by GC-MS analysis and comparison of the retention time with that of an authentic compound in GC. The content of p-cresol in fermented Gastrodia elata was decreased. A fermented sample of Latobacillus sakei for 2 days was reduced to 54.7%, when compared with a unfermented sample. The five parishin derivatives in Gastrodia elata were identified by HPLC-MS analyses, and a comparison of HPLC retention times with those of authentic compounds. When compared with parishin derivatives of an unfermented Gastrodia elata, those of Gastrodia elata fermented by L. sakei, increased to 18.3% for 2 days. Increases of about 14.0~38.4% of the total phenolic compounds and 57.4~77.3% total flavonoids were found in fermented extracts, by 3 lactic acid bacteria strains. They were compared with $97.1{\pm}2.9{\mu}g/g$ and $40.9{\pm}2.0{\mu}g/g$ in the unfermented control, respectively. The extracts of Gastrodia elata Blume that were fermented by lactic acid bacteria had higher DPPH free radical scavenging activity and FRAP reducing power than the unfermented control.

• Mycobiology
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• v.49 no.3
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• pp.223-234
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• 2021

Itajahya rosea was found growing in association with Leucaena leucocephala plants at Savitribai Phule Pune University campus in India. The species identity was confirmed by phylogenetic analysis based on ITS and LSU regions of rDNA, wherein, our fugus was placed along with I. rosea in phylogenetic tree. It represents first record of I. rosea from India. Frequent visitation by Drosophila species on I. rosea fruiting body particularly on gleba was observed. The Drosophila got attracted to the detached gleba under the laboratory conditions and even sometimes, they prefer to sit over the gleba as compare to their food banana. It suggested that I. rosea gleba or pseudostipe produces some compounds for attraction and feeding behavior of Drosophila species. Therefore, we characterized the volatile attractants produced by gleba and pseudostipe of I. rosea by GC-MS analysis. Nineteen compounds were identified from gleba while nine compounds were recovered from the pseudostipe. Out of them, blends of three abundant odor producing volatile compounds were reported namely, Hexadecane, Pentadecane and Nonadecane, which are responsible for attraction of Drosophila toward the gleba. Three fatty acids namely 9,12-octadecadienoic acid (Z,Z), hexadecanoic acid and benzoic acid ethyl ester produced are served as an appetitive signal through olfactory response of Drosophila, so the flies were feed on the gleba. Two pheromones' compounds, heneicosane and (+)-(5S,9S)-5,9-dimethylpentadecane, were also reported in pseudostipe and gleba, respectively, which play a role in Drosophila for breeding. Our study highlights an intriguing chemical ecology of fungus-Drosophila interaction.

• Journal of Life Science
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• v.20 no.1
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• pp.113-118
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• 2010

The study was conducted to identify volatile flavor compounds in concentrated onion extracts ($Oniwell^{TM}$) during storage at $30^{\circ}C$ for 150 days. A total of 23 compounds was detected in samples by solid phase microextraction (SPME)/GC/MSD, consisting mainly of 9 sulfur-containing compounds, 5 carbonyl compounds, 4 furans, 2 aromatic compounds and 3 miscellaneous compounds. The sulfur-containing compounds were major compounds with ranges of 75.8~67.3% of total volatiles. In particular, dimethyl trisulfide, with a cooked cabbage-like odor, was 50.1~42.1% of the total amount of sulfur-containing compounds. Two compounds, dimethyl disulfide (fresh garlic/green onion-like) and methylpropyl disulfide (garlic salt-like), were significantly increased with longer storage periods (p<0.05). Four furans (furfural, 2-acetylfurn, 5-methyl-2-furfural, furfurylalcohol), known as thermally generated flavors, ranged from 14.2~12.9% of total volatiles, and the amounts of 4 aldehydes (2-, 3-methylbutanal, benzaldehyde, phenylactaldehyde) derived from lipid oxidation during heat treatment were followed in that order. Accordingly, it was estimated that these 3 groups including sulfur-containing compounds, furans and aldehydes played key roles in flavors in concentrated onion extracts ($Oniwell^{TM}$) during storage.

• The Korean Journal of Food And Nutrition
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• v.17 no.4
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• pp.412-419
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• 2004

In odor to select optimum extraction methods of volatile compounds in beef extract powder(BEP) as basic data for the development of a new detection method of irradiated BEP, four extraction methods, such as solid phase microextraction with polar fiber(S-PD) and non-polar fiber(S-CD), purge and trap(P&T) and liquid liquid continuous extraction(LLCE) methods, were tested with gas chromatography/mass spectrometry method. A total of 106 volatile compounds including 22 hydrocarbons, 7 aldehydes, 6 ketones, 13 alcohols, 6 sulfur-containing compounds, 19 nitrogen-containing compounds, 6 aromatic compounds, 17 terpenes, 8 furans and 2 miscellaneous compounds were detected in BEP by four detection methods. The most compounds(62 compounds) were detected by S-PD method, followed by P&T(43), LLCE(38) and S-CD method(30). Among these methods, S-PD and P&T methods showed a complementary interrelationship to detect volatile compounds as S-PD method showed high detectabiltiy to all compound groups except hydrocarbons and ketones, which had high volatility and low molecular weight(less than RI 1200), but P&T method showed the contrary pattern to that of S-PD method. Moreover, the most of volatile compounds detected by S-CD and LLCE methods were also detectable by S-PD or/and P&T methods. Therefore, the simultaneous application of S-PD and P&T methods were selected as the optimum volatile extraction methods of BEP.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.787-795
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• 2001

For the developing natural fisheries flavoring substances using crustacea, the flavor constituents of enzyme hydrolysates from shore swimming crab (crab) and spotted shrimp (shrimp) were investigated. In taste-active compounds of both enzyme hydrolysates, total free amino acid contents of crab and shrimp enzyme hydrolysates were 5,226.7 mg% and 8,757.3 mg%, respectively. The major amino acids were taurine, glutamic acid, proline, asparagine, glycine, alanine, valine, leucine, lysine anserine and arginine. As for ATP related compounds, AMP was the principal component and small amounts of IMP was detected in both enzyme hydrolysates. In the quarternary ammonium bases, betaine was the principal component (593.8mg%), and contents of TMAO and betaine in both samples were 60.7 mg% and 850.0 mg%, 124.1 mg% and 755.9 mg%, respectively. The major components were Na, K, P and Cl in inorganic ions. The major fatty acids of both sample were 14 : 0, 16 : 0, 16 : 1n7, 18 : 1n9, 20 : 5n3 and 22 : 6n3, and composition ration of n3 polyunsaturated fatty acids of were 27.8% and 28.5%, respectively. Total 99~109 volatile compounds were detected as a cooked odor of crab and shrimp enzyme hydrolysates by SDE apparatus/gas chromatography/mass spectrometry. The volatile flavor compounds identified from cooked crab enzyme hydrolysate were composed of 6 acids, 10 alcohols, 7 aldehydes, 11 ketones, 1 ester, 5 phenols, 4 benzenes, 22 hydrocarbons, 1 furan, 21 nitrogen containing compounds and 11 micellaneous compounds. And the volatile flavor compounds indentified from cooked shrimp enzyme hydrolysate were composed of 13 acids, 10 alcohols, 6 aldehydes, 10 ketones, 3 esters, 2 phenols, 5 benzenes, 36 hydrocarbons, 1 furan, 14 nitrogen containing compounds and 8 micellaneous compounds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.4
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• pp.371-378
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• 1987

Free and total amino acids of before and after the heating of the small shrimps were analysed quantitatively, in order to confirm the role of amino acids as important precursors of cooked odor components. Differences of free amino acids contents of the three samples were slightly reconized but free amino acids contents of all sample decreased as about half by heating, It seems that decreased amino acids participate In volatile components of the Small Shrimps. (Sergia lucens Hancen, Euphausia Surperba and Euphausia pacifica Hancen). The amino-carbonyl model reaction was carried out, in order to confirm formation mechanism of volatile compounds of the small shrimps during cooking. The model systems constituted by diluted solutions. of glucose and amino acids (proline, taurine and betaine) the most containing in small shrimps. The volatile odor concentrates of model system were obtained by simultaneous distillation and extraction with Nickerson's apparatus. The odor concentrates of model systems(I, III) had not small shrimp-like odor and main compounds were 1,4,5,6-tetrahydro-2-acetopyridine and 2-acetyl pyridine. In model system II, hetero ring nitrogen and sulfur compounds identified in small shrimps were not did.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.39-44
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• 2002

To obtain the repression of off-odor and the improvement of food quality in b1ack bean chungkugjang (BBC), some baste components of BBC added with kiwi (BBCK) or radish (BBCR) and fermented at 42$^{\circ}C$ for 3 days were investigated. Although contents of free amino acids in BBC were lower than those of soybean chung-kugjang (SC), they increased by adding kiwi and radish homogenate to black bean, indication that two materials were effective to the enzymatic digestibility of soy protein during fermentation. Among organic acids, citric acid was the most abundant, followed by acetic acid and lactic acid. Fatty acid composition was high in the order of linoleic acid (44.28~54.24%), oleic acid (18.18~22.10%) and palmitic acid(9.93~15.51%). There was no significant difference in compositions of organic acids and fatty acids of chungkugjangs. Majar volatile compounds of BBC were 2.5-dimethyl parazine and trimethyl pyrazine. Contents of alkyl pyrazines that of contribute the characteristic aroma and flayer of BBCK and BBCR decreased as compared with those of SC, respectively. Uracil and UMP were major nucleic acid-related compounds in all four types chungkugjangs. Contents of the other nucleic acid-related compounds showed a similar trend in all chungkugjangs. In sensory evaluation, kiwi and radish were effective to repression of off-odor from chungkugjang. Sweet taste of stew of black bean chungkugjang was strong as compared with that of soybean chungkugjang, indicating that palatability of BBCK or BBCR was good.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2097-2104
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• 2000

Naturally occurring taste and odor problems include those produced by microorganism. notably algae and bacteria. The major compounds causing taste and odor are MIB and Geosmin which can cause earthy-musty at very low concentration 9ng/L and 4ng/L, respectively. Especially, the problem is very serious from summer to fall in source and finished water. It is well known that using PAC is one of the best technology to control these compounds in drinking water treatment. In this study, optimum dosage and dosing time of PAC were observed with the adsorption isotherm experiments in single and binary compounds. Also, the effect of natural organic matter(NOM) was investigated by using a natural water with JSW. The adsorption capacity of Geosmin was higher than MIB in both with NOM and without NOM. The adsorption capacity of Geosmin and MIB was 4 times lower with NOM than that of without NOM. which was caused by competition adsorption. When the initial concentration of Geosmin and MIB were 100ng/L in JSW, at least 4 hours of reaction time was needed to achieve 99% removal with 20mg/L of the PAC.