Technical Talk – October 2005
December 4, 2007
By Dr. John Michaelides
Acrylamide Under the Microscope
Question: What is acrylamide and how does it affect baked goods?
Answer: To understand what acrylamide is, first we need to address where it came from. The first report of the presence of acrylamide in processed foods came out in April 2002 when the Swedish National Food Administration and the Stockholm University reported its presence in a variety of fried and oven-baked goods. This report indicated that the formation of acrylamide is particularly associated with the high-temperature cooking process of certain foods that contain high levels of carbohydrates.
Since then, government institutions, food industry associations, and the food industry in general, have feverishly and extensively researched the presence, formation and possible prevention of the formation of this chemical in food products. Indeed, over 200 research projects have been initiated since that time.
But why is acrylamide being so energetically researched? Acrylamide is a chemical that is used for the production of polyacrylamide, which in turn is used for the treatment of drinking water to aid in the removal of impurities.
Polyacrylamide is also used in the wastewater treatment and in construction of dam foundations. There are very small amounts of acrylamide in polyacrylamide. Prior to these Swedish discoveries, the main health concerns with acrylamide were with workers exposed to it through their work environment, or people exposed to cigarette smoke.
Acrylamide is formed in processed foods by the reaction of the amino acid asparagine (which is found in high amounts in potatoes and cereals) and sugar (the major component of carbohydrates). Since 2002, various tests have confirmed that when foods containing asparagine and carbohydrates are exposed to heat, especially at temperatures above 100 C, the formation of acrylamide takes place.
So what are the implications of acrylamide in food? Two major reports summarize the recent issues and the safety of acrylamide in foods. The report of the findings of the Joint FAO/WHO Expert Committee on Food Additives, published in February 2005, deals with the issues of the various studies on its toxicity, the process of its formation in food products, and possible ways to reduce its presence in such foods. In this report, the findings indicate that trace amounts of acrylamide are formed during boiling (100 C), but the majority of the compound is formed when the temperature of the food reaches 120 C or higher. The chemical is most likely to accumulate during the final stages of baking, frying or grilling. It is prominent in foods containing high amounts of carbohydrates and low levels of protein. It is associated with the Maillard reactions, which are responsible for the browning of foods. The report noted that, world wide, a total of 6,752 food samples have been analyzed so far, and levels of acrylamide varied widely. Beyond the presence of carbohydrates and asparagine, the variation is most likely related to the variations of the cooking times and temperatures the foods are exposed to during the processing.
The FAO/WHO report also provides information on research carried out investigating ways to reduce the formation of the chemical in processed foods. For example, the European food industry reports a 30 to 49 per cent reduction of acrylamide formation in potato chips by introducing adjustments to the existing procedures. Likewise, significant reduction also resulted from process optimization of crisp bread production.
One possible basic way of reducing the formation of the acrylamide in processed foods is to reduce or eliminate the presence of the amino acid asparagine prior to exposing the food to the heat treatment. Experiments in food models have shown success by the use of the enzyme asparginase, which will selectively remove the amino-acid from the food materials. This is, however, only limited to foods that are slurried or liquefied, and cannot be applied to solid foods. Other attempts are being made to develop crops with low asparagine content. Still other remedies may include reformulation and changes in the acidity of the food product. This, however, will require consumer acceptance evaluations and substantial R&D efforts.
In a series of reports (the most recent published in June 2005), the U.S. Food and Drug Administration (FDA) has published its findings on the exploratory data on acrylamide in food. The reports provide preliminary analyses data of various brands of foods from 2002, 2003, and the most recent from October 7, 2004. The U.S. FDA emphasizes that these data are exploratory and are not an indication of the distribution of acrylamide in U.S. foods.
The recent discovery of acrylamide in foods has not been a devastating issue for the food industry due to the proper reaction by government bodies and the industry itself. Consumers did not react dramatically to the issue since the facts were clearly outlined up front. This is sensible since there remains uncertainty around the effect that acrylamide in foods may have on human health and safety. Indeed, other than the fact that some acrylamide has been found in human breast milk and the collection of data from workers environmentally exposed to the chemical, all research on the effect of acrylamide has been carried out in animal studies. Additionally, the studies of the absorption through the digestive system are limited.
As more data become available, the issue and concerns of the presence of acrylamide in foods will resurface from time to time. In the meantime, the prudent course for the food industry would be to look into additional ways to prevent the formation of this chemical in food products. Discovering new ways of minimally processing foods that are safe for human consumption will probably deal well with this issue, especially as it will also reduce the damage heat can cause to the healthy components such as vitamins and other antioxidants.
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