Finding acryl-amide--a reagent biochemists use to separate proteins, and a neurotoxin and suspected carcinogen--in fried and baked foods was surprising enough.1 What really puzzled food chemists was how it gets there. Now four research groups may have solved the mystery.
In papers from the University of Reading in England and the Nestle Research Center in Lausanne, Switzerland,2,3 and a report from Proctor & Gamble in Cincinnati, Ohio, delivered before the Association of Official Analytical Chemists, researchers concluded that it all comes down to organic chemistry.
At temperatures above 100°C, the amino acid asparagine--abundant in potatoes and cereal grains--bonds with 'reducing' sugars like glucose according to the Maillard reaction. Similar reactions create the familiar flavor and color compounds that make cooked food scrumptious. In the acrylamide pathway, a Maillard product called N-glycoside cleaves at a carbon-nitrogen bond, yielding the carbon skeleton and terminal amide group of asparagine, which transitions to acrylamide.
The three reports come on the heels of an alert from the Canadian Bureau of Chemical Safety in Ottawa, which warned food manufacturers about the link between asparagine and glucose in a letter dated Sept. 13. "Health Canada considers these preliminary findings important enough to release them. It is hoped that the food industry will be able to take immediate advantage of this information to find ways [to remediate the problem]," said James Lawrence, bureau director.
Maillard, however, may not be the only route to acrylamide. According to Robert Sanders, who heads the Proctor & Gamble group, their work shows that "asparagine reacts with ... 2-deoxyglucose, which does not undergo the Maillard reaction--producing acrylamide anyway. So, it is not [necessarily] the Maillard reaction that is producing acrylamide." Richard Stadler, leader of one of the other teams, is also circumspect. "This is a first indication of a feasible mechanism, but others may also be valid, since many different food categories are affected. More research is needed to better understand the formation of acrylamide. ... First studies have shown potential basic mechanisms, but these must be verified under food production cooking conditions."
With the new information breaking, a US Food and Drug Administration panel met to assess the significance of acrylamide in food. According to an FDA Draft Action Plan considered on Sept. 30, "Not enough is known about acrylamide formation to identify safe modifications to food processing techniques that will clearly prevent or reduce formation."4 The plan calls for further research.
Barry A. Palevitz (email@example.com) is a contributing editor.
1. B.A. Palevitz, "Plastic in my French fries?" The Scientist, 16:26-8, Sept. 2, 2002.
2. D.S. Mottram et al., "Acrylamide is formed in the Maillard reaction," Nature, 419:448-9, Oct. 3, 2002.
3. R.H. Stadler et al., "Acrylamide from Maillard reaction products," Nature, 419:449-50, Oct. 3, 2002.