Inhibition of N-nitrosomorpholine Formation by Lemon Juice

Abstract

Effect of lemon juice on formation of N-nitrosomorpholine was investigated on a reaction of morpholine and sodium nitrite. Lemon juice concentrate was added to the mixture of morpholine and sodium nitrite and formation of N-nitrosomorpholine was determined by HPLC analysis. Inhibitory effect on the N-nitrosomorpholine formation was 26% (in air) and 36% (in air), 16% (in N₂) and 35% (in N₂), respectively, by the addition of original juice and 2-fold concentrated juice. Inhibitory effect on the Nnitrosomorpholine formation was 5% (2 mM, in air), 23% (5mM, in air), 57% (10 mM, in N₂) and 100% (20mM, in air), 22% (2mM, in N₂) 57% (5mM, in air) and 100% (10mM and 20mM, in N₂) by the addition of ascorbic acid. Inhibition of ascorbic acid in lemon juice on the nitrosation of morpholine was 7.4%. Therefore the presence of inhibitory factors other than ascorbic acid in the lemon juice was estimated.