Inhibitory effects of citrus essential oils and their components on the formation of N-nitrosodimethylamine

Twenty-eight kinds of citrus essential oils and their components were studi ed for inhibitory effects on the formation of N-nitrosodimethylamine (NDMA) . The reaction mixture consisted of dimethylamine and sodium nitrite adjust ed at pH 3.6, in addition to essential oils and an emulsifying agent. The q uantification was determined by high-performance liquid choromatography mon itored at 220 nm. All of the essential oils inhibited the formation of NDMA . in the range of 20-85%. The oils of ujukitsu (Citrus ujukitsu Hort. ex Sh irai), yuzu (C. junos Tanaka), mochiyu (C. inflata Hort. ex Tanaka), and po nkan (C. reticulata Blanco cv. F-2426) inhibited the formation of NDMA much more effectively than other citrus oils. The inhibitory proportions of com ponents of citrus essential oils such as myrcene, alpha-terpinene, and terp inolene were as high as 80%.