In addition, since the amino acid is the starting point for key aroma compounds in bakery, it may also boost the flavour profile of bakery products, suggest findings published in the Journal of Agricultural and Food Chemistry.
“Proline is present at significant levels in both wheat and rye flour and has been identified as a potent precursor of roasted bread aromas such as 2-acetyl-l-pyrroline and 2-acetyltetrahydropyridine,” wrote the researchers from the University of Leeds, University of Northumbria at Newcastle, and the University of Reading.hey added.
In addition to proline, the amino acid tryptophan also cut the formation of acrylamide by 80 per cent, while cysteine and glycine also reduced formation of the suspected carcinogen by about 50 per cent, report the researchers, led by Georgios Koutsidis.
It is not the first time that amino acids have been employed to reduce the formation of acrylamide. Other approaches include converting asparagine into an impotent form using an enzyme, binding asparagine to make it inaccessible, changing the pH to alter the reaction products, cutting heating temperatures and times, and removing compounds from the recipe that may promote acrylamide formation.
Enzymes such as DSM’s Preventase and Novozyme's Acrylaway, work by converting asparagine into aspartic acid, thereby preventing it from being converted into acrylamide. The effect is a reduction in acrylamide in the final product by as much as 90 per cent.
“Although numerous investigations have studied the effect of amino acids on acrylamide, an optimized approach having a limited impact on the flavour and colour profile of foodstuffs is still to be commercially explored,” explained the researchers, led by.
Study details
Koutsidis and his co-workers tested the effects of the amino acids on acrylamide formation in a sealed low-moisture asparagine-glucose model system.
While certain amino acids, including valine, alanine, phenylalanine, and glutamine, did not significantly effect the rate of acrylamide formation, proline, tryptophan, glycine, and cysteine were found to perform the best at reducing formation of the suspected carcinogen.
“We report the significant mitigating effect of proline, which was the most potent amino acid in reducing the acrylamide levels in sealed low-moisture model systems,” wrote the researchers.
Acrylamide story
Acrylamide is a suspected carcinogen that is formed during by heat-induced reaction between sugar and an amino acid called asparagine. Known as the Maillard reaction, this process is responsible for the brown colour and tasty flavour of baked, fried and toasted foods.
Despite being a carcinogen in the laboratory, many epidemiological studies have reported that everyday exposure to acrylamide in food is too low to be of concern.
The compound first hit the headlines in 2002, when scientists at the Swedish Food Administration first reported unexpectedly high levels of acrylamide, found to cause cancer in laboratory rats, in carbohydrate-rich foods.
Since the Swedish discovery a global effort has been underway to amass data about this chemical. More than 200 research projects have been initiated around the world and their findings co-ordinated by national governments, the EU and the United Nations.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print. Article ASAP, doi: 10.1021/jf9014763
"Investigations on the Effect of Amino Acids on Acrylamide, Pyrazines, and Michael Addition Products in Model Systems"
Authors: G. Koutsidis, S.P.J. Simons, Y.H. Thong, Y. Haldoupis, J. Mojica-Lazaro, B.L. Wedzicha, D.S. Mottram