Acrylamide in food: mechanisms of formation and influencing factors during heating of foods

Background: In April 2002, the Swedish National Food Administration and a scientific group at the University of Stockholm jointly announced that they had shown acrylamide to be formed during the preparation of food and found it to occur in many foodstuffs. These new findings were clearly of concern to many types of industrial food processing as well as to home cooking. The Swedish Food Federation (Li) initiated and financed the formation of an expert committee to look into the chemical mechanisms. The present review is the final report of that expert committee. Design: The study identified, examined and put together facts and present knowledge on reaction routes for acrylamide formation in food and causal connections to cooking and food processing conditions. The results are based on literature surveys, examination of the analytical data published by the Swedish National Food Administration and other follow-up studies, contacts with international scientific networ ks, and observations from food companies. Results: The exact chemical mechanism(s) for acrylamide formation in heated foods is unknown. Several plausible mechanistic routes may be suggested, involving reactions of carbohydrates, proteins/amino acids, lipids and probably also other food components as precursors. With the data and knowledge available today it is not possible to point out any specific routes, or to exclude any possibilities. It is likely that a multitude of reaction mechanisms is involved. Acrolein is one strong precursor candidate, the origin of which could be lipids, carbohydrates or proteins/amino acids. Acrylamide is a reactive molecule and it can readily react with various other components in the food. The actual acrylamide level in a specific food product, therefore, probably reflects the balance between ease of formation and potential for further reactions in that food matrix. There are indications in support of that the Maillard reaction being an import a nt reaction route for acrylamide formation, but lipid degradation pathways to the formation of acrolein should also be considered. Conclusions: Reliable analytical methods to measure acrylamide in foods are available. Model studies are needed to identify precursors and reaction route(s) based on current hypotheses and to elucidate possible further reactions between acrylamide and other food components. Studies are needed to optimize formulation and processing conditions to minimize acrylamide levels, taking other product quality properties into consideration. Keywords: Acrylamide, cooking, food processing, heated foods, Maillard reaction.