The Maillard nonenzymatic browning reaction is known to cause serious reduction in the nutritionai value of foods. The reduced nutritionai value does not seem to be limited to the loss of amino acids, as supplementation of the diet with those amino acids does not completely restore its biologic value. When rats were fed a browned egg albumin diet and a control diet of equal protein quality for up to 12 mo, the rats fed browned diet showed enlarged cecums, livers, and kidneys and reduced weight gain. In addition, intestinal digestive enzyme activities decreased, and serum alkaline phosphatase and serum glutamic oxaloacetic transaminase (GOT) activities increased compared to the control group. The livers of the rats fed browned protein showed histopathologic changes including fatty change and an unknown pigment accumulation. The data indicate a possible cumulative toxic effect due to the long-term feeding of Maillard browned compounds.
The mutagenic activity of Maillard browned egg albumin was also tested. No mutagenic effect was observed. The products of the nitrosation of the Amadori compound fructosyl-L-trytophan were mutagenic, however, in strains TA 1535 and TA 100 of the Salmonella/mammalian microsome mutagenicity assay.