• The Korean Journal of Mycology
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• v.16 no.4
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• pp.193-203
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• 1988

The changes of pH, titrable acidity, nitrite and dimethylamine(DAM) content in the various different kinds of the rice wine staters during the fermentation were studied, and the changes of nitrosodimethymaine(NDMA) contents were also determined by High Pressure Liquid Chromatography. After 24hrs, fermentation rice wine starter, pH was generally decreased to below 5 and after full fermentation the acidities were from 0.51 to 0.89 as succinic acid. After 12hrs, fermentation nitrate contents were rapidly decreased. The large amount of nitrite was formed in the beginning of the fermentation. But by the increase in the acidity due to the further fermentation nitrite contents were gradually disappeared. Generally the DMA contents of each rice wine starter were kept unchanged. On completion of fermentation, NDMA contents of starter added with nitrite and DMA were 472.1 ppb. The starter added with DMA was 329.0 ppb, whereas the other added with nitrite was 229.0 ppb, and control without addition of nitrite and DMA was 24.4 ppb. But the rice wine sold in market was not detected any NDMA at all.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.7-14
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• 1981

Secondary amines are known as one of the precursors of nitrosamines which are potent carcinogenic compounds for human being and animals. In this study, trimethylamine and dimethylamine contents of salted, hot-air dried and sun dried samples of two commercial fishes, mackerel pike and seerfish were analyzed and quantitatively compared at three different temperature conditions. The formation of both secondary amines was more rapid at$10^{\circ}C\;and\;15^{\circ}C\;than\;at\;2^{\circ}C$. Residual amounts of trimethylamine oxide of salted samples were relatively higher than those of the other samples. Trimethylamine contents of hot-air dried mackerel pike and sun dried seerfish were relatively higher than those in the other samples, while those of salted samples were comparatively lower than those of others. Dimethylamine contents of hot-air dried samples were higher than those of the other samples, whereas those of salted samples were comparatively lower than those of the other samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.1
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• pp.117-125
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• 2016

Nitrite and dimethylamine (DMA) are the immediate precursors of carcinogenic N-nitrosodimethylamine (NDMA). This study investigated the effects of nitrite and nitrate contents in Chinese cabbage on changes in NDMA, nitrite, nitrate, and DMA contents during storage of kimchi. Contents of nitrite in Chinese cabbage 1 (HNC), Chinese cabbage 2 (MNC), and Chinese cabbage 3 (LNC) were $47.54{\pm}1.07$, $10.12{\pm}0.31$, and $6.10{\pm}0.09mg/kg$, respectively. Kimchi were assigned to one of the following three groups: kimchi used HNC (HNK), kimchi used MNC (MNK), and kimchi used LNC (LNK). HNK had higher levels of nitrite and nitrate than those in MNK and LNK after storage for 10 days and 20 days. DMA and NDMA contents decreased in all kimchi during the storage period. HNK had higher NDMA content than LNK until 20 days of storage. These results suggest that the contents of nitrite and nitrate in Chinese cabbage have significant effects on the formation of NDMA in kimchi.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.223-231
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• 1976

Dimethylamine(DMA) is known as an origin compound of dimethylnitrosamine which is responsible for carcinogenesis. It has been also reported that relatively large amount of DMA is distributed in fish muscle, particularly in salted and fermented fish. Tn this experiment, the degradation products of protein and trimethylaminoxide(TMAO) by the temperature conditions of $17^{\circ}C\;and\;27^{\circ}C$ in the course of anchovy fermentation with $22\%$ of salt were analysed, and the formation of DMA was discussed. Protein-N decreased through the whole fermentation period ill the conditions of $17^{\circ}C\;and\;27^{\circ}C$ whereas amino-N increased proportionally to the decrease of protein-N, and the increasing rate of amino-N was remarkably faster at $27^{\circ}C$ than at $17^{\circ}C$. Trimethylamine(TMA) gradually increased with the decrease of TMAO till 69th day of fermentation, hereafter tended to slightly decrease. It seemed that the difference in fermentation temperature affects on the formation of DMA and obviously on the variation of TMAO. Both DMA and TMA content were inversely varied with the TMAO content. Correlation coefficient of DMA to TMAO in quantitative variation was shown -0.811 at $17^{\circ}C$ and -0.865 at $27^{\circ}C$ of fermentation temperature respectively. The results suggested that the formation of DMA during fermentation of anchovy was attributed to the degradation of TMAO showing, contributorial ratio of 0.66 at $17^{\circ}C$ and 0.75 at $27^{\circ}C$ respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.245-253
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• 1979

Trimethylamine and dimethylamine contents of salted, hot-air dried, sun dried and boiled-dried samples of three commercial fishes, common mackerel, gizzard-shad and sardine, were analyzed and quantitatively compared at two different temperature conditions. The formation of both secondary amines was more rapid at $25^{\circ}C$ than at $10^{\circ}C$. And the content of dimethylamine in small sardine was comparatively higher than that in the other samples at both temperatures. Residual amounts of trimethylamine oxide of Halted common mackerel, gizzard-shad and boiled-dried small sardine were relatively higher than those of the other samples. Trimethylamine contents of sun dried samples were relatively higher than in the other samples, while those of boiled-dried small sardine was comparatively lower than those of the others. Dimethylamine content of sun dried samples were higher than those of the other samples, whereas those of boiled-dried small sardine and salted common mackerel were comparatively lower than those of the other samples.

• Journal of the Korean Society of Food Culture
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• v.9 no.2
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• pp.125-130
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• 1994

This study was intended to observe the effect of the addition of soused shrimp(5%, 10%) and/or cooked glutinous rice flour(2.5%) on the changes of low molecular nitrogen compounds content of Kimchi during fermentation at $10^{\circ}C$ for 14 days. The pH, total acidity, free sugar, nitrite, dimethylamine(DMA) and volatile basic nitrogen(VBN) contents were measured. The nitrite contents were approximately 0.16 to 1.31 mg/Kg at the inital stage of fermentation. It was found that the nitrite contents of Kimchi samples with 10% soused shrimp$(S_2,\;GS_2)$ were relatively high among the Kimchi samples. However, nitrite was not detected after the stage of optimum maturity in all Kimchi samples. The dimethylamine(DMA) content of Kimchi samples were increased during the fermentation with increasing the soused shrimp concentration. Cooked glutinous rice flour enhanced the DMA production of Kimchi with soused shrimp. DMA content were 0.93-1.2 mg/kg at initial stage end 1.6-2.26 mg/kg at final stage of fermentation of the Kimchi with soused shrimp. As the fermentation period increased, the VBN contents of Kimchi samples with soused shrimp$(S_1,\;S_2,\;GS_1,\;GS_2)$ were apparently higher than those of Kimchi samples without it(C, G). Though the soused shrimp enhanced the volatile basic nitrogen production but cooked glutinous rice did not affected VBN production during Kimchi fermentation.

• YAKHAK HOEJI
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• v.30 no.4
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• pp.163-168
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• 1986

Thirteen compounds were synthesized by condensing the N-heterocyclic amines (piperidine, pyrrolidine, morpholine) and secondary aliphatic amines (dimethylamine, diethylamine) with 3,4-methylenedioxyphenylalkenoic acid chlorides for developing CNS depressants. Among them, N, N-diethyl-3,4-methylenedioxycinnamamide (IX) and N, N-dimethyl-5-(3,4-methylenedioxyphenyl)-2, 4-pentadienoic acid amicle (XII) exhibited strong activity in antagonism against pentylenetetrazole-induced convulsion, strychnine-induced convulsion and maximal electroshock seizure. N, N-Dimethyl-3, 4-methylenedioxycinnamide (VIII) showed more potent activity in antagonism against strychnine-induced convulsion and maximal electroshock seizure and in the prolongation of hexobarbital sleeping time.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.269-269
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• 2012

수산화인회석(Hydroxyapatite)는 뼈와 이빨의 무기물 주성분으로서, 칼슘과 인산염으로 구성된다. 우리는 수산화인회석의 합성에 용융열 합성법(molten salt method), 수열 합성법(hydrothermal method), 용매열 합성법(solvothermal method)을 사용하였으며, pH 조절과 각기 다른 용매를 사용하여 다양한 형태의 수산화인회석을 합성하였다. TEM과 SEM을 이용하여 크기와 모양이 제어된 수산화인회석임을 확인할 수 있었다. 합성된 수산화인회석을 이용하여, 전이금속 Ruthenium cation을 Hydroxyapatite 표면에 ion-exchange 반응을 통하여 도입하였으며, ICP를 통하여 Ru 함양을 정량하였다. 합성된 Ruthenium Hydroxyapatite (Ru-HAP)를 이용하여 dimethylamine borane를 통한 수소 발생을 확인하였다.

• Journal of Surface Science and Engineering
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• v.26 no.4
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• pp.175-182
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• 1993

Electroless plating of nickel was studied electrochemically in the presence of complexing agents. Nickel sulfate solution with dimethylamine borance(DMAB) as the reducing agent was used. Effects of temperature pH, concentration and complexing agents-citric acid, EDTA, tartaric acid-were studied.Experimental meas-urements showed that the rate of electroless nickel deposition was closely related to electrochemical parame-ters such as temdperature, pH, concentration and the properties of complexing agets.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.390-393
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• 2005

N-nitrosodimethylamine (NDMA), a potent carcinogenic, has recently been observed at drinking water supply systems in USA and Canada. The NDMA formation was studied as a function of chloramine concentration (0.001-0.1 mM) at a fixed dimethylamine (DMA) concentration of 0.05 mM at different initial pH (6, 7, 8). It was found that the NDMA formation rate varied with pH values. The formation of NDMA increased with increasing chloramine concentration and showed maximum yields of 2.4% and 1.6% at pH 7 and 8, respectively. A good correlation ($r^2>0.99$) was observed between the molar ratio (chloramine/DMA) and NDMA formation at pH 7 and 8. Linearity of the NDMA formation appeared to be related to chloramine concentrations.