Strecker aldehydes are regularly found in the low boiling point fraction of volatile compounds of processed plant foods. They are produced via the Strecker degradation of amino acids. The formation of 3-methylbutanal (3-MB) in a glucose- and leucine-containing low moisture model system and the formation of acetaldehyde, 2-methylpropanal, 2-methylbutanal and 3-MB in plant powders showed a linear pH dependence. The formation of the Amadori rearrangement product (ARP) fructose-leucine (fru-leu) in the model system, in contrast to it's degradation, was not influenced by the pH. The formation of the 3-deoxyosone [3-deoxy-d-erythro-hexos-2-ulose (3-DH)] by degradation of fru-leu was slower at pH 7 than at pH 5 suggesting that it is either less stable at pH 7 or being formed to a lesser extent. Further experimental results suggested that enolisation and retro aldol reactions of reducing sugars also contribute to the production of Strecker aldehydes as the pH is increased, by creating α-dicarbonyl compounds. The appearance of fructose in the glucose-containing model systems indicates enolisation reactions in the course of a Maillard reaction.