Effects of food components and additives on the formation of nitrosamides.

The effects of food components and food additives on the formation of nitrosamides were studied. Citrate accelerated nitrosamide formation from nitrite and various precursors, such as ureas, urethanes, guanidines and amides. The accelerating effects of citrate on the formation of methylurea and ethylenethiourea were larger at higher pH values. The formation of most nitrosamides was not accelerated by thiocyanate, which is known to catalyze the formation of nitrosamines. Compounds having carboxyl groups tended to accelerate the nitrosation of methylurea. Nitrosation of methylurea was inhibited by thiols, polyphenols, alcohols, sorbic acid, dl-alpha-tocopherol etc., due to possibly competition for available nitrite.