This paper describes for the first time a specific mechanism by which acrylamide is formed by the reaction of asparagine with dicarbonylic intermediates in the Maillard reaction. The presence of acrylamide had previously been reported in many heat-treated foods and particular interest in this substance comes from the belief that it is a probable carcinogen in man. The result indicates that the mechanism of acrylamide formation is closely linked to the chemistry of flavor development when foods are subjected to high temperature, e.g., as in roasting or frying. A number of research groups worldwide were working at the same time as us to elucidate this mechanism, and for this reason our paper attracted considerable interest.

Yes, whilst there was a circumstantial link between food browning and acrylamide levels, this is the first report of a chemical mechanism which proves the link at a molecular level and identifies the specific amino acids involved. The paper also demonstrates an unusual effect of temperature on the yield of acrylamide which subsequently we find is a possible feature to control its formation in food.

When foods are heated as in baking, frying, roasting or toasting, brown colors and "cooked" flavors are formed because sugars react with proteins and their components, the amino acids, in the so-called Maillard reaction. One of these components, which is particularly abundant in plant-derived foods, is asparagine. This is a naturally occurring amino acid which is essential for plants to store nitrogen in the form of proteins. When this amino acid reacts with substances formed during food browning, the compound acrylamide is formed. The paper explains the mechanism of this chemical reaction to understand how the formation of acrylamide is related chemically to color and flavor in food. Acrylamide has attracted considerable interest in the field of food safety because it could cause cancer in man, and it has been detected at part per million levels in many heat-treated, plant-derived foods. A detailed understanding of the chemical mechanism allows us to suggest methods to reduce acrylamide formation in food.

Don Mottram has an extensive publications record in the chemical mechanisms of "cooked" flavor formation through the Maillard reaction. His laboratory is state-of-the-art with respect to the analysis of trace organic components of foods. Bronek Wedzicha has similarly an extensive publications record in the chemical mechanisms of browning with a specific interest in the kinetics and the modeling of this process in food. We share an interest in the way that common reaction intermediates participate in the two processes of flavor and color formation.

Very soon after hearing of the discovery of acrylamide in food, we formulated the hypothesis that a significant route to its formation had to be related to the Strecker degradation of asparagine, which is part of the Maillard reaction. Our research was to test this hypothesis explicitly by designing model systems to confirm the unique reaction behavior of asparagine and methionine with glucose and with Strecker reaction precursors. We realized that there would be worldwide "competition" to identify the mechanism and we were, therefore, fortunate to benefit from the skillful analytical work of Andrew Dodson to confirm our hypothesis, in time for submission of the manuscript in late July 2002. This paper is an excellent example of what may be achieved through synergy between two research groups (at Reading and Leeds) with complementary interests in Maillard chemistry and illustrates how "Fast Breaking" ideas can emerge spontaneously in such an interactive environment. Currently we are applying our combined expertise in mechanism and kinetics to understand the factors which determine kinetic control of acrylamide formation with a view to an understanding of the scientific principles underlying the control of acrylamide formation when food is heated.

Bronek L. Wedzicha
Professor of Food Science
Procter Department of Food Science
University of Leeds
Leeds, United Kingdom

Donald S. Mottram
Professor of Food Chemistry
School of Food Biosciences
The University of Reading
Reading, United Kingdom