C03031, C03047 and C03048: Mechanism of the formation of acrylamide in cooked foods and factors affecting its formation during thermal processing

Study Duration: June 2005 to October 2007

Contractor: The University of Reading, The University of Nottingham and The University of Leeds

It has been shown that the genotoxic chemical acrylamide is present in certain cooked foods. The EC Scientific Committee on Food (SCF) subsequently recommended that levels of acrylamide in food should be as low as reasonably achievable.

In June 2002, a WHO/FAO consultation recommended that an understanding of the formation of acrylamide in heated foods is needed so that formulation, processing and cooking conditions can be optimised to minimise acrylamide levels.

Various mechanisms of formation of acrylamide have been proposed, with possible sources including the amino acid asparagine, and acrolein. The aim of this project is to determine the precise mechanism and kinetics of acrylamide formation in plant-based food, in particular potato and cereal. The project will aim to determine a kinetic model, which will provide a generic framework to predict the effects of processing conditions, composition, and the food matrix on acrylamide levels

Initially, the mechanism of acrylamide formation will be investigated by:

• Determining the effect of reactants and reaction conditions on acrylamide formation in model systems, using competition studies with amino acids, and carbonyl compounds.
• Investigating the kinetics of the formation of acrylamide in relation to chemical composition and reaction conditions (temperature and pH) of simple model systems.

These results will then be used to formulate a kinetic model which will be applied to acrylamide levels in real foods, allowing predictive modelling of acrylamide formation in foods of given composition and under specific processing conditions.

Initial investigations involved the evaluation of various matrices as a platform to study the kinetic parameters affecting acrylamide formation. Partly gelatinised and freeze dried Waxy Maize Starch (WMS) was found to be the most appropriate platform for analysing acrylamide formation due to its reduced reactivity, homogeneity and low initial moisture.

Kinetic studies on the model system conducted in parallel at three sites provided data that correlated well with work that has been published previously on food systems. Kinetic study investigations on acrylamide formation were affected by sugar type, the presence of amino acids, initial moisture and temperature.

Studies, looking at different sugars, carbonyls and amino acids were conducted and the outcomes were combined to provide an improved version of the initial kinetic model. Investigations into the effect of different food additives on acrylamide formation were mainly targeted on the use of pH modifiers. Other routes of acrylamide formation i.e. through acrolein and or acrylic acid do not seem to be as important as the established Maillard reaction of asparagine with carbonyls.

The outcomes from the study gave rise to the initial production of the acrylamide toolkit, which attempts to give the manufacturing industry the basis to predict the final level of acrylamide in any given product. The toolkit has limitations that may affect the efficacy of the result obtained.