ARCHIVED - Major pathway of formation of acrylamide in foods and possible approaches to mitigation

Since the initial finding that acrylamide could be formed from naturally-occurring substances in certain foods as the result of high temperature processing, Health Canada’s scientists have been undertaking studies to determine how acrylamide is formed in situ during the cooking of carbohydrate-rich foods.

A model system was constructed by using a mixture of suspected acrylamide precursors to simulate what might occur in food preparation (for example, in potatoes during cooking). Glucose and a mixture of free amino acids naturally present in potatoes were used in the initial experiments. Finding that similar levels of acrylamide were produced when only asparagine was reacted with glucose under the same conditions, suggested that asparagine was the main precursor of acrylamide. Similarly, acrylamide was not detected in a model system lacking glucose or heated at 120º or 140ºC, rather than 175ºC. Subsequently, fructose and sucrose were also found to be effective in this reaction.

Health Canada’s researchers were among the first in the world to report on the major mechanism of formation of acrylamide in food to the international scientific community ( Acrylamide in Foods: Occurrence and Sources. Becalski, A.; Lau, B. P.-Y.; Lewis, D.; Seaman, S. Abstracts of 116th Annual AOAC International Meeting, Los Angeles, CA, Sept 22-26, 2002; AOAC: Gaithersburg, MD, 2002; pp 125-126 and Acrylamide in Foods: Occurrence, Sources, and Modeling. Becalski, A.; Lau, B. P.-Y.; Lewis, D.; Seaman, S.W. Journal of Agricultural and Food Chemistry. 2003, 51(3), 802-808) .

(Abstract: Acrylamide in Foods: Occurrence, Sources, and Modeling)

The reaction responsible for the major pathway of formation of acrylamide is shown in Figure 1. It is important to note that heat treatment to the temperatures encountered during frying or baking is necessary for the formation of acrylamide out of the identified precursors.

Figure 1. Formation pathway of acrylamide in foods.

* Glucose, fructose, decomposition products of sucrose and other sugars as well as other suitable intermediates (e.g. aldehydes).

This discovery represents represented a breakthrough in our understanding of the occurrence of acrylamide in food. It is also fundamental to investigations to develop measures to reduce human exposure to acrylamide from foods.

Establishing the principal pathway of formation of acrylamide in foods allowed investigation of the effect of some parameters for reducing concentrations of acrylamide in potato-based products (chips, fries, etc.) Preliminary results indicate that the overall reduction of acrylamide formation can be achieved by:

• reducing the concentrations of reactants needed for acrylamide formation - notably reducing sugars;
• increasing the concentrations of reactants (e.g. other amino acids) competing with asparagine in the Maillard reaction;
• changing processing conditions (lower pH, lower temperature, shorter heating times), thus altering the rate of formation of acrylamide;
• scavenging already-formed acrylamide by other chemical compounds (via addition to the double bond).

Health Canada’s scientists have reported on their latest findings in this area, in a peer-reviewed scientific document (Acrylamide in French Fries, Influence of Free Amino-Acids and Sugars, A. Becalski, B. Lau, D. Lewis, S. Seaman, S. Hayward, M. Sahagian, M. Ramesh and Y. Leclerc, J. Agric. Food Chem., 2004, 52, 3801-3806.)

(Abstract: Acrylamide in French Fries:  Influence of Free Amino Acids and Sugars)

Mitigation measures that can be adopted by either food processors or by consumers to reduce the levels of acrylamide in the course of food preparation are being investigated and discussed within the scientific community. Some simple measures to reduce acrylamide formation in food prepared in the home are described in the document "Acrylamide - What you can do to reduce exposure".