Lower cooking temperatures combat acrylamide, more evidence

Acrylamide hit the headlines in 2002 when scientists at the Swedish Food Administration first reported unexpectedly high levels of this potential carcinogen, found to cause cancer in laboratory rats, in carbohydrate-rich foods cooked at high temperatures. Since the Swedish discovery a global effort has been underway to deepen knowledge about this chemical, with more than 200 research projects initiated around the world, and their findings co-ordinated by national governments, the EU and the United Nations. The €799 billion European food industry has also started to tackle the issue, in particular looking at ways processing can reduce the levels of acrylamide: a chemical that appears to form as a result of a reaction between specific amino acids and sugars found in foods reaching high temperatures in their cooking processes. According to the industry's body, the CIAA, recent processing investigations have achieved a 30 to 40 per cent reduction in acrylamide. Breakthrough research by UK scientist Professor Don Mottram at the University of Reading has contributed considerably to our understanding of how acrylamide is created in foods. Mottram's team suspected it could be created by a reaction between an amino acid called asparagine, which occurs naturally in relatively high levels in potatoes and other cereals, and sugar. Tests confirmed that when the amino acid is heated, it does react with sugar to create acrylamide, a process called the Maillard reaction. This occurs at temperatures above 100°C (212°F). Their findings were published in Nature 419, 448-449 (2002). Recent research to come out of the US Texas A&M University confirms these findings, revealing that lowering cooking temperature is an "easy and effective way" to reduce acrylamide in fried foods. Graduate student Claudia Granda, at the Texas A&M university , altered cooking times, pressure and temperatures to see if acrylamide levels could be decreased. She found lowering the pressure permitted the use of lower temperatures to 118 C (244 F) during vacuum frying. Granda also increased the cooking time to eight minutes and found much less acylamide was formed. Potato crisps are normally fried at 165 C to 180 C (330 F to 360 F) for four minutes. An added benefit of the vacuum frying, says Granda, is that the potato crisp does not lose its crispy texture. Because potato varieties have varying levels of reducing sugars, Granda tested different types. Storage temperatures, according to Granda, also affected the reducing sugars in the potatoes. Lower storage temperatures increased the amount in potatoes. The researcher also found that the type of cooking oil had no effect on acrylamide levels. But with the lower cooking temperatures, less oil (28 per cent compared to 40 per cent) was retained on a 'wet basis' in the end product than at normal cooking temperatures.

Lower cooking temperatures combat acrylamide, more evidence

New research from the US backs growing evidence that food makers wanting to slice acrylamide from their fried food products should opt for lower cooking temperatures.

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