Cut the sugars to beat cancer-causing compound

A wave of concern ripplied through the food industry on 24 April last year when Swedish scientists discovered unexpectedly high levels of acrylamide in carbohydrate-rich foods heated to high temperatures.

One month after the Swedish Food Administration broadcast the concerns, the UK's Central Science Laboratory (CSL) confirmed the findings.

The results propelled the food industry into working together, itself a rare event, to find out more. "I've never seen the food industry work together like this - working collectively to find solutions. The food industry has definitely acted responsably,"​ UK food scientist Prof. Don Mottram, a leading researcher into acrylamide, told a conference in Germany last month.

Professor Mottram is currently working with six different companies - normally competitors - to investigate the formation of acrylamide.

Based at the University of Reading, and in conjunction with B L Wedzicha at the University of Leeds, Mottram recently provided an important breakthrough into the understanding of the origin of acrylamide in cooked food (Nature​ 419, 448-449 (2002).

Mottram and colleagues showed how acrylamide could be formed from food components during heat treatment as a result of the Maillard reaction.

"We found that asparagine, a major free amino acid in potatoes and cereals, is a crucial participant in the production of acrylamide by this pathway,"​ Mottram told the audience.

The landmark study by the Swedish scientists in April last year identified higher levels of the potential carcinogen acrylamide in crisps, chips and some snacks, in stark contrast to meats, fish, vegetables and some nuts that demonstrated low levels.

"Asparagine is essential for the plant to grow. There are high asparagine levels in some plant foods, but low in animal foods. For potatoes levels reach 940mg per 100g - 40 per cent of the total. This could explain why higher levels found in plants, as opposed to meat food,"​ said Mottram.

"Asparagine will react with reducing sugars to give acrylamide,"​ added the scientist.

High temperatures also seem to play a key role in acrylamide formation. Temperatures in excess of 125°C are required for the formation of acrylamide in the asparagine and glucose model system, he said.

So crucially, what are the implications for the food industry? Select raw materials with low asparagines and sugar content could be the pathway today, advised Mottram.

A recent two day workshop in Brussels organised by the Commission in October 2003 gave a run down on acrylamide in food.

Of note, with respect to potatoes advice from the workshop to the food industry is to not only select varieties with low levels of reducing sugars but also use pre-treatments involving pre-blanching or soaking in water at room temperature.

Lowering the pH of the soaking water and avoiding the cold storage of potatoes also seems to help and in light of recent research, notably from Mottram and colleagues, dipping part-cooked cut potato products in glucose solutions should be avoided.

Discussions and advice from the event are due to be published shortly on the DG Sanco food safety​ web site.

But research on acrylamide is still at a nascent stage, despite a global effort that sees the World Health Organisation (WHO) co-ordinating scientists on acrylamide research projects across the world.

The European Commission and the European Food Safety Authority (EFSA) have developed a database​ to summarise the research activities in the EU.

The Commission's Joint Research Centre​ is co-ordinating work on analytical methods and is collecting data on the levels detected in different foods. For 'long-term research needs,' the Commission has included the topic in the 6th Framework Programme for research and technological development.