• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.2
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• pp.223-229
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• 2003

An amine rich diet with nitrate was incubated in simulated saliva, gastric juice, kale juice, and its ascorbate and methanol soluble portions (5, 10, 15 and 30 mL) for 1 hr at 37$^{\circ}C$ and N-nitrosodimethylamine (NDMA) was detected in the digestion sample, Kale juice and its ascorbate and methanol soluble portions at 30mL inhibited NDMA formation by 60.1$\pm$4.4%, 49.3$\pm$1.2% and 50.1$\pm$2.0%, respectively. The methanol soluble portion was further fractionated by preparative-LC (prep-LC). Nitrite-scavenging effects of 7 methanol soluble portion (Kl, K2, K3, K4, K5, K6 and K7) in kale juice were 2.0 ~56.2%. Among seven fractions, K3, K4, K5 and K7 exhibited weakly on nitrite scavenging effect. Fraction Kl and K2 inhibited NDMA formation by 71.0 and 65.5%, respectively. Fraction Kl and K2 was further separated by prep-LC into 6 subfractions (Kla, Klb, Klc, K2a, K2b and 2nc). Those subfractions inhibited NDMA formation by 40.9 ~80.4%. The K2a subfraction was screened by MS, $^1$H-NMR, $^{13}$ C-NMR and DEPT spectrum.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.244-250
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• 2017

Dimethylamine (DMA), nitrate, nitrite, and biogenic amines (BA) are precursors of carcinogenic N-nitrosamines. This study investigated contamination levels of DMA, nitrate, nitrite, and BA in various types of Korean commercial kimchi such as Baechu kimchi, Kkakduki, Chonggak kimchi, Matkimchi, ripened Baechu kimchi, and Baek kimchi. The average DMA, nitrate, and nitrite levels in Baechu kimchi were 29.7, 2,178.8, and 3.0 mg/kg, respectively. Low levels of DMA and nitrate were detected in Kkakduki. Tryptamine, putrescine, cadaverine, tyramine, and spermidine were detected in kimchi with exclusion of Baek kimchi and Chonggak kimchi. Tryptamine in Baek kimchi was only present in trace amount, and spermidine was not detected in Chonggak kimchi. The average tryptamine, putrescine, cadaverine, tyramine, and spermidine levels in Baechu kimchi were 15.0, 64.6, 18.0, 44.0, and 7.8 mg/kg, respectively. A low level of tyramine was detected in Kkakduki. In addition, contamination of N-nitrosodimethylamine (NDMA) was detected in Kkakduki at a level of $1.38{\mu}g/kg$. Daily exposure to NDMA in the consumer only group was estimated using average daily Kkakduki consumption and average body weight of the total population. The estimated daily intake of NDMA by Kkakduki was $2.31{\times}10^{-7}mg/kg\;b.w./d.$ The margin of exposure to NDMA for the general population was 259,924. Accordingly, the health risk from NDMA caused by intake of Kkakduki was considered to be very low.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.63-70
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• 1998

The changes of contents of trimethylamine oxide nitrogen (TMAO-N), trimethylamine nitrogen (TMA-N), dimethylamine nitrogen (DMA-N), nitrite nitrogen (nitrite-N), nitrate nitrogen (nitrate-N) and N-nitrosamine (NA) of salt-fermented small shrimp were investigated during fermentation. The contents of TMAO-N decreased, while TMA-N and DMA-N increased during fermentation in all samples. Contents of nitrite-N decreased in the samples supplemented with sodium nitrite during fermentation, whereas the formation of N-nitrosodimethylamine (NDMA) increased. Treatment of ascorbic acid revealed inhibiting effort on NDMA formation compared with the control. The model system was used for the evaluation of ascorbic acid (inhibitor) or thiocyanate (promoter) on the formation of NDMA using salt-fermented small shrimp supplemented with sodium nitrite, The optimum pH for the formation of NDMA was 3.5, and ascorbic acid inhibited the formation of NDMA whereas thiocyanate promoted.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.606-613
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• 1997

The changes of contents in trimethylamine oxide nitrogen(TMAO-N), trimethylamine nitrogen(TMA-N), dimethylamine nitrogen(DMA-N), nitrite nitrogen(nitrite-N), nitrate nitrogen(nitrate-N) and the effect on the formation of N-nitrosamine(NA) during fermentation were investigated with salted anchovy added different amounts of sodium nitrite, sodium nitrate and ascorbic acid, respectively. When the sodium nitrite was added in salted anchovy, the contents of nitrite-N was decreased during fermentation . Whereas the formation of N-nitrosodimethylamine(NDMA ) was increased . Contents of TMAO-N was decreased, while TMA-N and DMA-N were increased during fermentation in all samples. Addition of ascorbic acid inhibited the formation of NDMA significantly. The formation of NDMA was inhibited by 81.3% at the concentration of 130mM as compared with non-added the control group. The aqueous model system was used for the evaluation of ascorbic acid(inhibitor) or thiocyanate (promoter) on the formation of NDMA using salt-fermented anchovy added with sodium nitrite. The optimum pH on the formation of NDMA was shown to be 3.8, and ascorbic acid inhibited the formation of NDMA whereas thiocyanate promoted. NDMA was not detected in the salt-fermented anchovy (control sample). However it is a possibility to form carcinogenic NDMA in stomach if both saltfer-mented anchovy and the materials contained abundant nitrite or nitrate were took in.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.446-453
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• 2010

This study was investigated nine nitrosamines in small tributary rivers, sewage treatment plants (STPs) and drinking water treatment plants. They are N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosopyrrolidine (NPYR), N-nitrosodi-n-propylamine (NDPA), N-nitrosomorpholine (NMOR), N-nitrosopiperidine (NPIP), N-nitrosodi-n-butylamine (NDBA) and N-nitrosodiphenylamine (NDPHA). The nine nitrosamines were analyzed by gas chromatography mass spectrometry (GC/MS) using solid phase extraction (SPE) with a coconut charcoal cartridge. Among the nine nitrosamines, NDMA, NMEA, NDEA, NDPA NDBA and NDPHA were detected in small tributary rivers and sewage tretment plants. In small tributary rivers, NDMA, NMEA, NDEA, NDPA, NDBA and NDPHA were obtained as ND~16.4 ng/L, ND~17.7 ng/L, ND~102.4 ng/L, ND~455.4 ng/L, ND~330.1 ng/L and ND~161.0 ng/L, respectively. Also NDMA, NMEA, NDEA, NDPA and NDBA were investigated ND~821.4 ng/L, 22.5~55.4 ng/L, 53.2~588.5 ng/L, ND~56.6 ng/L and ND~527.9 ng/L in STPs, respectively. In drinking water treatment plants, NMEA and NDEA concentration were increased to as high as 38.8 ng/L after ozonation process. However nitrosamines were decreased subsequent biological activated carbon (BAC) treatment process. It was supposed that nitrosamines were formed by $O_3$ oxidation and were removed by biodegradation of BAC.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 2005.10a
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• pp.28-28
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• 2005

• Journal of Food Hygiene and Safety
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• v.33 no.5
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• pp.361-368
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• 2018

N-nitrosamines are probable or possible human carcinogens, which are produced by the reaction between secondary amines and nitrogen oxide in the acidic environment or by heating. Common risk assessment procedure involves the comparison between exposures expressed in the unit, mg/kg body weight/day and the Health-Based Reference dose expressed in the same unit. This procedure is suitable for the policy decision-making and is considered as inappropriate for the consumers to get information about their dietary decision-making. Therefore, the distributions of NDMA (N-nitrosodimethylamine), NDBA (N-nitrosodibutylamine), the six N-nitrosamines (NDMA, NDBA, NDEA (N-nitrosodiethylamine), NPYR (N-nitrosopyrrolidine), NPIP (N-nitrosopiperidine), and NMOR (N-nitrosomorpholine) in the menus grouped based on the presence of main ingredients and cooking methods were analyzed to generate consumer-friendly information regarding food contaminants. Recipes and intakes were taken from 2014 to 2016 KNHANES (The Korean National Health and Nutrition Examination Survey) and only the data from ages of 7 years or older were used. The contamination data were collected from the 2014~2016 Total Diet Study and all the analysis were performed using R software. Rockfish, eel, anchovy broth and pollock were mainly exposed to N-nitrosamines. In terms of cooking methods, soups and stews appeared to contain the highest amount of N-nitrosamines. Cereals, fruits, and dairy products in the ingredient categories, and rice dishes and rice combined with others in recipe categories had the lowest level exposure to N-nitrosamines. In case of N-nitrosamines, unlike other cooking related food contaminants, boiled dishes such as soups and stews and dishes mainly consisting of fishes and shellfishes had highest level of exposure, showing a large discrepancy with the previous thought of processed meat is the main source of N-nitrosamines.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.389-398
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• 2018

A nationwide survey of 8 N-nitrosamines in finished water samples from drinking water treatment plants (DWTPs) in Korea was conducted. The samples were pre-treated by solid-phase extraction (SPE) and analyzed using a gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). According to the study results, four N-nitrosamines (NDMA, NDEA, NMOR, NDBA) were detected for three consecutive years, NMEA and NPYR were only found in samples collected in 2013. Two of these N-nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), have received attention and were the most commonly detected. The concentration of NDMA and NDEA in this study ranged from $0.002{\mu}g/L$ to $0.013{\mu}g/L$ and in $0.001{\mu}g/L$ to $0.008{\mu}g/L$, respectively. In comparison to studies performed in EPA(UCMR2), the concentrations of NDMA (from $0.002{\mu}g/L$ to $0.630{\mu}g/L$) and NDEA (from $0.005{\mu}g/L$ to $0.100{\mu}g/L$) observed in the this study were low.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.400-405
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• 1998

This experiment was conducted to study occurrence of N-nitrosamine (NA) and its precursors such as nitrate and nitrite. For the experimental samples, 26 kinds of commercial hams and 30 kinds of sausages produced in Korea were purchased. The nitrate and nitrite were positive in all of the collected samples; nitrate levels were by average 4.4~9.2 mg/kg and nitrite ones were by average 1.3~3.6 mg/kg. The contents of nitrate and nitrite were detected higher in sausage than in ham. Especially, nitrate contents were contained higher in lyoner sausage prepared with the mixture of meat and fish, while nitrite contents were contained higher in the meat only mixture. N-nitrosodimethylamine (NDMA) among the analyzed 7 kinds of NA was detected only in ham and sausage; its contents were outstanding in lyoner sausage which was prepared with only meat and pork sausage, and then regular ham was the next one in its order, but its contants were detected by average $<0.5\;\mu\textrm{g}/kg$ in press hams added vegetable.

• Journal of Life Science
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• v.8 no.5
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• pp.509-519
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• 1998

The effect of N-Nitrosodimethylamine(NDMA) on the glycoconjugates of rat lingual salivary gland was examined by prelectin histochemical methods. Sprague-Dawley rats weighing about 250-300g were divided into control and experimental groups. Each rat of experimental groups was administrated NDMA(17mg/kg) orally and sacrificed in 3, 6, 12, 24, 48, 72, 96 and 120 hours after NDMA administration. The regional differences and change of glycoco-njugates were elucidated by prelectin histochemical methods, such as periodic acid Schiff's(PAS) reaction, alcian blue (AB) pH 2.5, AB pH 0.4, AB pH 2.5-PAS, aldehyde fuchsin(AF) pH 1.7-AB pH 2.5 and high iron diamine(HID)-AB pH 2.5 staining. The major morphological changes in the von Ebner’s gland of NDMA administrated groups were withering and des-truction of serous acini, diminution and disappearance of cytoplasmic granules and vacuolation in cytoplasm of serous cells, and mucinous changes of duct epithelial cells. These changes were noted in NDMA administrated groups for 12 to 72 hours. In the lingual mucous gland of NDMA administrated groups, the major morphological changes were enlargement, fusion and destruction of mucous acini, loss of cytoplasmic granules and vacuolated generation in cytop-lasm of mucous cells, and mucinous change of duct epithelial cells. These changes were severe in NDMA administra-ted groups for 12 to 72 hours. In NDMA administrated groups of lingual von Ebner's gland for 12 and 72 hours, the neutral glycoconjugates be-come diminished remarkably compared to the control group. The decreased amount of neutral glycoconjugates tended to be gradually recovered from 96 hours group. The acidic glycoconjugates which were not detected in control group were found in a few serous cells of these gland of NDMA administrated groups for 6 to 48 hours and 120 ho-urs. The remarkable decrease of neutral and acidic glycoconjugates was observed in the lingual mucous glands 3, 24 and 48 hours after NDMA administration, and the striking decrease of acidic glycoconjugates was found in 72 hours groups. Among acidic glycoconjugates, sulfated glycoconjugates tended to decrease in NDMA administrated groups for 72 hours, while sialic glycoconjugates were increased in NDMA administrated groups for 3, 12 and 48 hours.