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The degradation of nitrite and the inhibition towards formation of carcinogenic nitrosamines by melanoidins, produced from the glucose-glycine system were investigated at various conditions. The degradation ofnitrite was highest at pH1.2 (29%), when the ratio ofmelanoidins to nitrite was 1 : 3. The inhibition towards formation of nitrosamines by melanoidins had the same tendency as the degradation of nitrite, the inhibition also being highest at pH 1.2 (99%). In addition, melanoidins after nitrite treatment exhibited a little higher mutagenicity and much stronger desmutagenicity than those of the original melanoidins. The change of the structure of melanoidins after treating with nitrite was also investigated by HPLCand CP-MASNMR.The Maillard reaction is very important in food manufacturing, and its results can be either desirable or undesirable.Recently, re-

The desmutagenic activities of low-molecular weight melanoidins (LM-MEL, MW 500-1000) and nondialyzable melanoidins (ND-MEL, MW above 1000) prepared from a glucose-glycine reaction system were examined by Ames' test on such mutagens/carcinogens as nitro or amino compounds of aromatics or heterocycles, azo compounds, nitroso compounds, and epoxides. ND-MEL and LM-MEL exhibited a desmutagenic activity of 25-75% against mutagenic aromatic or heterocyclic compounds such as aflatoxin B1, B[α]P, 2-aminofluorene, 4-aminobiphenyl, and 2-aminonaphthalene, as well as heterocyclic amines, using S. typhimurium TA98 in the presence of S9 mix. In the case of using S. typhimurium TA100 in the absence of S9 mix, ND-MEL and LM-MEL showed a desmutagenic activity of 20-50% against 2-nitrofluorene, 4NQO and 2-nitronaphthalene. The strong desmutagenic activity of MEL from various kinds of amino acids, peptides, or egg albumin hydrolyzates with glucose was also observed against Trp-P-1. Furthermore, MEL had marked desmutagenic activity against the Trp-P-1 activated by S9 mix and synthetic N-OH-Trp-P-2.

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