• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.28-32
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• 1999

A total of 18 marketing radish kimchi samples, 7 species of kakdugi, 6 species of chonggak kimchi and 5 species of dongchimi were analyzed for their N nitrosamine levels by gas chromatography thermal energy analyzer(GC TEA). N nitrosodimethylamine(NDMA) was the only volatile N nitr osamine found in this study and was positive in all collected samples. The average amount of NDMA for kakdugi, chonggak kimchi and dongchimi were 22.9, 13.7 and 23.4 g/kg, and the range were 3.3~ 35.9, 2.6~50.6 and 4.5~65.1 g/kg, respectively. The range of pH for all samples were 3.6~5.4 and the average recovery of internal standard(N nitrosodipropylamine) were 82.0%. NDMA amounts were highest in chonggakkimch (50.6 g/kg) and dongchimi(65.1 g/kg) among collected samples.

• Culinary science and hospitality research
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• v.10 no.2
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• pp.30-37
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• 2004

국내에서 유통되고 있는 수입어류 8종에 대한 발암성 물질인 N-nitrosamine콰 전구물질들의 함량을 분석하여 위생학적 기초자료를 제공하고자 하였다. 수입어류의 질산염 및 아질산염 함량은 각각 0.4∼12.8 mg/kg 및 N.D∼l6.0 mg/kg 이었다. Dimethylamine 함량은 1.0∼70.6 mg/100g 이었으며, Trimethylarnine 함량은 15.4∼70.6 mg/100g이었다. 수입어류 8종에 대한 발암성 물질인 N-nitrosamine은 N-nitrosodimethylamine (NDMA) 만 검출되었으며, 이들의 NDMA 함량은 2.1∼102.2mg/kg으로 러시아산 가자미에서 가장 높게 검출되었다. 또한 아르헨티나산 냉동새우는 35.3 $\mu\textrm{g}$/kg, 러시아산 냉동대구에서도 30.6 $\mu\textrm{g}$/kg으로 높은 함량을 보였다.

• Journal of Food Hygiene and Safety
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• v.17 no.4
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• pp.201-205
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• 2002

When it added to each designed diet groups such as control, nitrate rich, amine rich and nitrate-amine rich diet under simulated gastric conditions, effect of kumquat (Fortunella mararita) juice on formation of N-nitrosodimethylamine (NDMA) was studied. Inhibition on NDMA formation was the highest in the amine rich diet, as 69.4 $\pm$2.4%, when the juice of 10m1 added to its digestate. Phenolic portion of $C_{18}$ sep-pak cartridge in kumquat juice were separated into 20 kinds of a phenolic compounds using HPLC. These phenolic fractions such as faction no. 1, 2, 3, 4 and 5 inhibited from 3.0 $\pm$ 1.2% to 66.5 $\pm$2.0% NDMA formation in the reaction system which was mixture of nitrite and dimethylamine.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.6
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• pp.677-682
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• 2006

This study was conducted to investigate the effect of garlic extracts on electron donating ability nitrite-scavenging activity and N-nitrosodimethylamine (NDMA) formation. Content of total phenolic compounds was the highest in ethyl acetate extract. Electron donating ability was significantly increased with increasing sample concentration, as $88.0{\pm}1.53%$ from ethyl acetate extract and $77.5{\pm}0.8%$ from butanol extract in concentration of 10 mg/mL. Butanol extract from garlic with highest nitrite scavenging activity and inhibition effect of NDMA formation exhibited $96.9{\pm}0.75%$ and $68.6{\pm}1.15%$ in concentration of 10 mg/mL, respectively. The butanol extract was fractionated into 5 fractions using prep-LC. Nitrite-scavenging activity and inhibition effect of NDMA formation were excellent in fraction III, which further fractioned into 3 subfractions (III-a, III-b and III-c) using prep-LC. Of the 3 subfractions, its activity was the highest in the subfraction III-c. Therefore butanol extract of garlic was suggested to be effective inhibitor of NDMA formation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.12
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• pp.1568-1575
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• 2008

This study was performed to determine alleviating effects of green tea (GT) on the N-nitrosodimethylamine (NDMA) toxicity to mucins in the rat lingual salivary glands. Sprague-Dawley rats were divided into five groups: untreated (Control), one week-NDMA administrated (NDMA), one week-GT administrated after NDMA for one week (NDMAGT), one week-NDMA administrated with GT (GTNDMA), and one-week NDMA administrated with GT after GT for one week (GTGTNDMA). The mucin properties were elucidated by periodic acid Schiff (PAS) reaction, alcian blue (AB) pH 2.5, 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 lingual von Ebner's glands of NDMA group showed some changes such as contraction and destruction of the serous acini, decrease and disappearance of the cytoplasmic granules, vacuolation of cytoplasm, and the mucigenous duct cells. Also, in the lingual mucous glands, enlarged lumens, fused acini, disappearance of granules, vacuolation of cytoplasm, and mucigenous duct cells were observed. All the GT administrated groups had a tendency to recover. GTGTNDMA group recovered almost up to the state of the control group. The lingual von Ebner's glands of NDMA group showed a decrease of neutral mucin and the lingual mucous glands showed a decrease of both neutral and acidic mucins decreased in comparison with control group, although mucous acini secreting strong sulfomucin decreased while those secreting non-sulfomucin (sialomucin) increased. All the GT administrated groups had a tendency to recover. The degree of recovery in the GTNDMA group was stronger than in NDMAGT group and that of the GTGTNDMA group was almost up to the state of the control group. Plus, lingual von Ebner's glands of GTGTNDMA group contained much more neutral mucin than in the control group. In conclusion, it is suggested that NDMA exhibit the toxicity which affects on the mucin properties and which green tea alleviates.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.3
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• pp.279-289
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• 2018

N-nitrosodimethylamine (NDMA) is a class of disinfection byproducts and a frequently detected nitrosamine with carcinogenic potentials. This review summarizes NDMA precursors, their formation mechanisms in chloraminated water, and mitigation strategies. Understanding the formation mechanism and characteristics of precursors is essential for developing a mitigation strategy. Dimethylamine (DMA), the most widely studied NDMA precursor, has an NDMA molar yield up to 3%. In comparison, a subset of tertiary amines, e.g., pharmaceuticals, generate up to 90% upon chloramination. Potent NDMA precursors, are characterized by their negative partial charge, low planarity values and molecular weight, and high bond length and $pK_a$ values. A nucleophilic substitution of tertiary amine on chloramine is a key reason for the high NDMA yield from the most potent NDMA precursors. The distribution and fate of NDMA in surface water, aquifers, and its formation in the distribution system can be mitigated through two strategies: (1) degrading or/removing NDMA after its formation and (2) pre-treatment of its precursor's prior chloramination.

• Journal of Life Science
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• v.16 no.5
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• pp.794-798
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• 2006

A tomato (Lycopersicon esculentum cv. Naomi F1) juice was separated into ascorbate and phenolic portions using a Sep-pak $C_{18}$ cartridge, and its each portion was tested for inhibition of N-nitrosodimethylamine (NDMA) formation. Ascorbate and phenolic portions of tomato juice inhibited NDMA formation by $81.37{\pm}0.25%$ and $72.03{\pm}0.25%$, respectively. The phenolic portion was further fractionated by prep-HPLC and inhibitory effects of NDMA formation by 4 fractions $(1{\sim}4)$ from tomato juice was tested under the different pH conditions (pH 1.2 and 4.2). Fraction 2 inhibited NDMA formation by $50.10{\pm}0.46%$ (pH 1.2) and $64.30{\pm}0.20%$ (pH 4.2), respectively. Fraction 2 was further separated into 4 subfractions $(2a{\sim}2d)$. Subfraction 2b especially inhibited NDMA formation by $70.62{\pm}0.45%$ (pH 1.2) and $75.30{\pm}0.45%$ (pH 4.2). This subfraction was confirmed o-coumaric acid through the analysis of GC-Mass spectrum, $^1H-NMR$ and $^{13}C-NMR$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.9
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• pp.1302-1309
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• 2016

N-Nitrosodimethylamine (NDMA) is formed through reactions between dimethylamine (DMA) and nitrite. Jeotgal, a traditional Korean salted and fermented seafood, contains a large amount of DMA and is an ingredient of kimchi condiment. This study investigated the effects of amount and type of Jeotgal on changes in NDMA and its precursor contents during storage of kimchi. NDMA was found in all 23 Jeotgal samples, and DMA in nine salted and fermented shrimp samples showed levels ranging from 16.5 to 58.9 mg/kg (average of 30.9 mg/kg). The seven salted and fermented anchovy juice samples showed DMA levels ranging from 21.7 to 44.4 mg/kg (average of 34.5 mg/kg). Kimchi was assigned to one of the following five groups: kimchi without salted and fermented anchovy juice and salted and fermented shrimp (control), kimchi with small amount of salted and fermented anchovy juice (AK1), kimchi with large amount of salted and fermented anchovy juice (AK2), kimchi with small amount of salted and fermented shrimp (SK1), and kimchi with large amount of salted and fermented shrimp (SK2). SK2 had higher DMA content than SK1 during storage while AK2 had higher DMA content than AK1 after storage for 10 days. Nitrite contents of AK1 and SK1 were higher than those of AK2 and SK2 after storage for 20 days. NDMA content was significantly higher in SK2 than in SK1 after storage for 0 and 10 days, and NDMA content in AK2 was significantly higher compared to that in AK1 after storage for 0 days. The DMA and NDMA contents decreased in all kimchi samples during storage. The effects of amount and type of Jeotgal on DMA and NDMA contents were reduced after storage for 20 days. The results suggest that the content and type of Jeotgal have significant effects on formation of NDMA in kimchi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.2
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• pp.149-153
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• 1992

The antimutagenic effect of green-ye1low vegetables on the mutagenicities induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) and N-nitrosodimethylamine (NDMA) in Salmonella assay system and also their inhibitory effect on AZ-521 human gastric cancer cells were studied. Twenty-four items from twenty six kinds of vegetables(92%) revealed antimutagenic activity toward MNNG (p< 0.0l, 0.05). Perilla leaf, Korean cabbage, cauliflower, lettuce, mustard leaf, water dropwort, small water dropwort, carrot and burdock inhibited the mutagenicity more than 80%. The methanol extracts of the vegetables also showed the antimutagenic activity toward NDMA (p< 0.01, 0.05). Especially, perilla leaf, kale, soybean sprout and onion inhibited more than 80% of the NDMA induced mutagenicity in S. typhimurium TA100. Small water dropwort and perilla leaf exhibited the strong inhibitory effect (97~100%) on the growth of the AZ-521 human gastric cancer cells. Soybean sprout, water dropwort, broccoli, crown daisy, green red pepper, red pepper leaves, spinach, cabbage and sweet potato also inhibited growth of the cancer cells (p < 0.001~0.05).

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.413-416
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• 2008

Recently, the results of vital tissue test showed that nitrosodimethylamine (NDMA) as a disinfection by-product (DBP), could be regarded as a carcinogen because a tumor was observed in organs. U.S.EPA indicated 0.7 ng/L as exposure concentration of NDMA based on a risk assessment target with a lifetime cancer risk of $10^{-6}$. Several recent studies have shown that UV oxidation could remove NDMA. However, UV oxidation is uneconomical and can reform NDMA after treating. In addition, the treatment mechanism of adsorption has not been founddue to the uncertainty of NDMA pathway. In addtion, NDMA has a radioisotope $^{14}C$-labeled which can be analyzed at low concentration of NDMA by Liquid Scintillation Counter (LSC). This study has investigated NDMA determination using LSC at an extremely low range from 1 to 100 ng/L and NDMA removal by powdered activated carbon (PAC) adsorption. For $^{14}C$-NDMA by LSC, the highest correlation over 99% between count number and NDMA concentrationwas obtained with possibility of $^{14}C$-NDMA concentration up to 1 ng/L. In the presence of PAC ranging from 50 to 10,000 mg/L, $^{14}C$-NDMA was removed from 18% to 97% for Sigma-Aldrich corporation (S-A co.) and from 9% to 93% by PAC for Daejung corporation (Dj co.). Hence it was found that the removal efficiency by PAC adsorption could vary depending on PAC types from different companies. For PAC adsorption capacity of $^{14}C$-NDMA using the Freundlich isotherm, $K_f$ and 1/n of PAC from S-A co. were $2.67\times10^{-3}$ ng/mg and 1.009, while those of PAC from Dj co. were $1.30\times10^{-3}$ ng/mg and 0.994, respectively. Thus, PAC from S-A co. showed twice higher adsorption capacity than Dj co.