Sugar-amine browning reactions

K. Eichner and M. Ciner-Doruk, Formation and decomposition of browning intermediates and visible sugar-amine browning reactions, in Water Activity Influences on Food Quality, L. B. Rockland and G. F. Stewart (eds), Academic Press, New York, 1981, 567-603. 

Figure 1. Amadori rearrangement of glycosylated proteins. Integration of known reactions leading to browning in sugar-amine systems. (Reproduced from Ref. 101. Copyright 1953, American Chemical Society.)...

Because of their significant electrophilic character, aldehydes are often unstable and will react with nucleophiles. For example, a common reaction of aldehydes is the formation of a hemiaminal with amines. If the amine is a primary amine, the hemiaminal can dehydrate to form an imine as shown in Figure 21. The reaction of aldehydes with primary and secondary amines is a well-studied reaction pathway because it is a common reaction pathway of reducing sugars and amino acids, and this reaction pathway is known as the Maillard reaction (40). In the case of amino acids and sugars, this reaction leads to discoloration, or browning. This reaction will be discussed in greater detail in the Amines-Maillard Reaction section. 

Figure 1. Sugar-amine Maillard browning reactions Two pathways to melanoidins and byproducts. (Reprinted with permission from ref. 12. Copyright 1967 Avi Publishing.)...

T. Hayashi and M. Namiki, Formation of two-carbon sugar fragment at an early stage of the browning reaction of sugar with amine, Agric. Biol. Chem., 1980, 44, 2575-2580. 

J. E. Hodge, F. D. Mills, and B. E. Fisher, Compounds of browned flavor derived from sugar-amine reactions, Cereal Sci. Today, 1972, 17, 34. 

One of the most known formulation reaction in the pharmaceutical industry is the reaction between an amine (primary or secondary) and a carbohydrate (e.g., sugar) is known as the Maillard reaction (the browning reaction due to mixing of a reduced sugar and an amine) [13]. One of the examples of the Maillard reaction is fluoxetine HCl [14] Figure A15-6. The details of how to avoid this reaction in the formulation is outlined in Section 15.5 [Impact of excipients on Degradation products of API(s)]. 

Despite the current popularity of the polyphenol theory, a completely satisfactory scheme for the occurrence of humic and fulvic acids in diverse geologic environments has yet to be established. In practice, all pathways may be operative, but not to the same extent in all environments or in the same order of importance. A lignin pathway may-predominate in wet sediments, such as peats and swamps. The drastic conditions existing in soils under a harsh continental climate (e.g., some Mollisols) may favor humus synthesis by sugar-amine condensation. The disappearance of amino acids from buried sediments has been attributed to the formation of brown nitrogenous polyelectrolytes by reaction with reducing sugars (Stevenson, 1974). 

Soy protein products undergo the typical non-enzymatic browning reaction (Maillard reaction) in the presence of reducing sugars. The course of this reaction is similar to that of other proteins which have been studied in some detail. This subject has been reviewed recently by Feeney, Blankenhorn, and Dixon (49) as a special aspect of the carbonyl-amine reactions of proteins. 

The Maillard browning reaction is also often implicated in the development of mutagens in heated foods. Dichloromethane extracts of browning reaction model systems (heated sugar plus amine mixtures) are mutagenic in the Ames test using... 

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