Abstract
The formation of carcinogenic N-nitrosodimethylamine (NDMA) and asymmetrical alkyl N-nitroso compounds by reacting nitrite or nitrogen dioxide gas (NO2 gas) wiht asymmetrical tertiary amines (N, N-dimethylglycine, DMGly, 2-dimethylethanolamine, DMEla) and quaternary am-monium compounds (betaine, choline and neurine) have been examined under varying reaction conditions and the results obtained are summarized as follows:
When asymmetrical quaternary ammonium compounds were allowed to react with nitrite in buffer solutions of pH 2.0 or 5.0 at 37° or 90°C, no appreciable amounts of NDMA, N-nitroso-sarcosine (NSAR) and N-nitrosomethylethanolamine (NMELA) were formed. A high rate of NSAR formation was noted from DMGly, and also a high level of NMELA was formed from DMEla when these amines were allowed to react with nitrite in a buffer solution of pH 2.0 at 90°C; in contrast, rates of these nitrosamine formation apparenty decreased when the reactions were allowed to proceed at pH 5.0 and 9°C. Concerning nitrosation reaction of amines occurring with NO2 gas under the conditions simulated to dried squid cooking, no appreciable amount, or lnly trace quanti-ties of NDMA were formed from sarcosine DMGly and betaine, while both sarcosine and DMGly gave yields of more than 1% of NSAR, and that of betaine was about 0.1%.
