Nichtenzymatische Bräunung

Summary Carbonyl derivatives produced by lipid oxidation, e. g. aldehydes and hydroxyketones, can react with free amino groups with formation of various coloured condensation products. The reaction is rather slow at room temperature, but it is accelerated by moderate increase of temperature so that it may be finished within one hour. The main products formed in the beginning of the reaction have the composition corresponding to imines. In presence of excess amine groups, these products probably predominate even after longer reaction times. In the case of media where aldehydes are present in excess, and, particularly, in acid media, compounds containing two or even more aldehydee radicals for each amino group are formed by further aldolization of primary reaction products. In the case of hydroxy ketones, no reactions analogous to aldolization take place, on the contrary, one hydroxyketo group can bind two amino derivatives.