Acrylamide: fried food's unwelcome ingredient
Scientists have produced acrylamide for decades — but the compound has only attracted widespread attention in the last decade.
Acrylamide was first synthesized in 1949 and used as a chemical intermediate in the manufacture of some plastics — including some food packaging.
Small amounts of acrylamide are also used in the synthesis of dyes, ore processing, adhesives, paper and textile coatings, permanent press fabrics, sugar beet juice clarification, binders for seed coatings and foundry sand, and printing ink emulsion stabilizers.
Acrylamide has also been used in the construction of dam foundations and tunnels. It is an odourless solid that takes the form of either flake-like crystals or a 30-50 per cent aqueous solution.
But take a potato, cut it into bite-sized pieces and drop them into a vat of hot oil and you wind up with a plate full of acrylamide-laced vegetable.
How does acrylamide form in food?
There are three components needed for acrylamide to form in food: a naturally occurring amino acid called asparagine, a naturally occurring sugar like glucose, and high cooking temperatures.
The temperature required depends on the properties of the food.
Initial studies suggest that at temperatures above 175 C, the level of acrylamide in deep-fried potato products increases considerably.
The German Federal Institute for Risk Assessment reported in December 2002 that the acrylamide content rises dramatically in french fries, from approximately 300 micrograms per kilogram at a cooking temperature of 175 C to 1,100 micrograms per kilogram at 180 C.
Studies have also shown that the type of potato and the storage method may also influence acrylamide formation and the acrylamide content in the deep-fried end product, because the sugar composition varies from potato to potato.
However, at a conference of the American Chemical Society in Boston in August 2007, a team of Swiss researchers reported that they have found acrylamide in dried fruits. Their study suggests that acrylamide may be capable of being formed at relatively mild conditions through reactions that are still not fully understood. The researchers found the highest levels of the compound in dried pears and prunes.
Is acrylamide a threat to human health?
According to the World Health Organization Expert Committee on Food Additives and Contaminants, acrylamide may pose a risk to human health. The committee released its report at a meeting in Rome in 2005.
Two years later, a study by researchers at the Harvard University School of Public Health reported that there did not appear to be a link between acrylamide and breast cancer in American women. The study involved 100,000 women who were followed over a 20-year period. It found that the incidence of breast cancer among women who consumed relatively high levels of acrylamide was about the same as for women who consumed low levels of the compound.
In February 2008, Health Canada included acrylamide in the fifth batch of chemicals it was evaluating as possible risks to human health. On Feb. 21, 2009, the government released its draft screening assessments of those chemicals. It said acrylamide is "proposed to be of concern to human health."
That means the government could add it to its list of toxic chemicals and use the Food and Drugs Act to limit the inadvertent production of acrylamide in processed foods. Interested parties have until April 22, 2009 to comment.
What types of foods are likely to contain acrylamide?
French fries and potato chips tend to contain the highest concentration of acrylamide. It's also found in other foods, such as cookies, breakfast cereals and bread, and those processed at high temperatures, such as coffee, roasted almonds, and grain-based coffee substitutes.
Again, it's not clear at what level acrylamide may pose a risk - health officials say the beneficial aspects of some foods that contain acrylamide, such as whole grain cereals and breads, likely outweigh the risks.
Health Canada says it's collaborating with the food industry to find ways of reducing levels of acrylamide in processed foods.
How do I minimize my risk?
You could stop eating potato chips and french fries — or just eat them once in a while. If you make fries at home, you could take the following steps:
- Cook your fries at no higher than 170-175 C.
- Don't overcook them; a nice golden colour is good.
- Avoid dark-coloured fries. They've been in the oil too long and will have higher concentrations of acrylamide.
- Don't store potatoes at temperatures below 8 C. Lower temperature storage can increase the components that lead to the formation of acrylamide.
- Wash or soak your freshly cut potatoes before cooking them. This can reduce the components that lead to the formation of acrylamide.
Other steps you could take include toasting your bread lightly and removing the crusts. The crust tends to contain higher levels of acrylamide than the interior of the bread — but the levels in bread are still well below the levels in french fries and potato chips.
If you want to avoid acrylamide and still eat your spuds, you can boil them. Health Canada says its tests show boiled potatoes are acrylamide-free.