Abstract
Many vegetables produced in Japan contain large amounts of nitrate that may be converted into nitrite in the oral cavity and afford carcinogenic nitrosamines in the stomach. On the other hand, vegetables contain ascorbate and other components that may affect the formation of nitrosamines. In this study, nitrosamine formation from vegetables with high nitrate content produced in Japan was examined under simulated oral cavity and stomach conditions. Extracts of chingensai, komatsuna and itomitsuba were digested with nitrate reductase and subsequently treated with an excess of morpholine at pH 3.0. The amount of N-nitrosomorpholine produced from each of the vegetable extracts was not affected by the vegetable components in the extracts. Addition of a large amount of ascorbate was required to decrease nitrosamine formation from the extract. The results indicated that nitrosamine formation from these vegetables could not be prevented by other components in the vegetables.
