Carcinogen found in French fries:

Scientists at the TU München detect glycidamide in chips and French fries

18.08.2008, Press releases

The discovery of acrylamide in heated foodstuffs sent shockwaves around the world in 2002. Subsequent improvements in production methods enabled the food industry to reduce levels of acrylamide. However, further investigations revealed that the levels of acrylamid found in food has virtually no toxicological impact. In fact, the carcinogen glycidamide, a substance that is also generated when potato products are heated, is seen as a much greater threat. Now for the first time ever, scientists at the Technische Universitaet Muenchen (TUM) have shown the direct presence of glycidamide in potato chips and French fries.

It has long been known that acrylamid is broken down in the liver to the highly carcinogenic substance glycidamide. And although scientists suspected that glycidamide is produced when foods are heated, its actual existence in foodstuffs has never been proven. But now, a team of experts headed by Dr. Michael Granvogl at the TUM’s Chair of Food Chemistry has done just this. They have not only detected the dangerous substance directly in different types of potato chips and French fries, but have also developed a procedure for measuring the amount of glycidamide present in these foodstuffs.

The scientists have thus far examined ten different types of crisps, three types of pre-cooked French fries as well as regular home-cooked French fries. In all of the samples tested, the team found levels of glycidamide ranging from 0.3 to 1.5 micrograms per kilogram. Although the same products typically contain 300 to 600 micrograms of acrylamide per kilogram, the scientists still see these comparably low levels of glycidamide as a cause for concern, as glycidamide is a significantly more dangerous substance. A similar study carried out by scientists at the University of Kaiserslautern revealed that even the smallest amounts of glycidamide triggered mutations in mammal cells.

Tests with different kinds of frying fats also led Granvogl to a further worrying discovery. The lowest concentrations of glycidamide were detected in slices of potato fried in saturated oils such as palm oil, a widely used fat for frying. In contrast, significantly higher levels of glycidamide were detected in tests with sunflower oil - an equally popular frying oil which contains unsaturated fats. Different studies have shown that unsaturated fats react with oxygen in the air to create hydroperoxides, which in turn react with acrylamide to produce glycidamide.

Since polyunsaturated fatty acids are regarded as being healthy, sunflower oil is frequently used for cooking potato chips and other potato products. The researchers’ results now show that this may not be such a healthy option after all. “Many oils are labeled ‘suitable for frying and baking’, even oils that contain high levels of unsaturated or even polyunsaturated fatty acids,” explains Dr. Granvogl. “Our initial results indicate that oils with saturated fatty acids are actually the better option here.”

Improvements in industrial production methods led to dramatic cuts in levels of acrylamide in food. And now, TUM scientists are working on further developing this new process to make it available to standard commercial labs. The objective is to enable the food industry to reduce glycidamide levels to an absolute minimum. Prof. Schieberle, head of the Chair of Food Chemistry and the group’s leader, has now created a PhD position to investigate the influence different types of oil have on glycidamide levels.


Published in Journal of Agricultural and Food Chemistry: J. Agric. Food Chem., 56 (15), 6087–6092, 2008

Contact:

Dr. Michael Granvogl
Technische Universität München
Department Chemistry
Lichtenbergstr. 4
85748 Garching
Tel.: 089-289-13268
Fax: 089-289-14183
E-Mail: Michael.Granvogl@lrz.tum.de
Internet: www.leb.chemie.tu-muenchen.de

Prof. Dr. Peter Schieberle
Technische Universität München
Department Chemistry
Chair of Food Chemistry
Lichtenbergstr. 4
85748 Garching
Tel.: 089-289-13265
Fax: 089-289-14183
E-Mail: peter.schieberle@ch.tum.de
Internet: www.leb.chemie.tu-muenchen.de

Kontakt: presse@tum.de

More Information

http://pubs.acs.org/cgi-bin/abstract.cgi/jafcau/2008/56/i15/abs/jf800280b.html