The authors, in findings published in the International Journal of Food Science and Technology, found the reduction of acrylamide in white bread using pea flour (P. sativum) was not significant but that the acrylamide level can be reduced by supplementation with 5 per cent pea flour in wheat bran and wholegrain breads.
Acrylamide is formed during high temperature cooking by a heat-induced reaction between sugar and an amino acid called asparagines. Known as the Maillard reaction, this process is responsible for the brown colour and tasty flavour of baked, fried and toasted foods.
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. And an EFSA statement in 2005 said acrylamide is both carcinogenic and genotoxic (which means it can cause damage to the genetic material of cells).
The authors of this study said their aim was to investigate the effect of pea-originated asparaginase on acrylamide content, colour and sensory properties of white wheat, wheat bran and whole-grain wheat breads.
Asparaginase is an enzyme that catalyses the hydrolysis of asparagine into aspartic acid and ammonia. The authors said that Pedreschi et al. (2008) reported that the application of commercial asparaginase enzyme in dough resulted in 55 per cent decrease in acrylamide content, in 75 per cent degradation of asparagine, and no detrimental effect on taste and colour of gingerbread.
Furthermore, the scientists report that previous research has indicated that P. sativum has the highest asparaginase activity of the various plant sources.
Two-day germinated pea flour was used at 0 per cent, 1 per cent, 3 per cent and 5 per cent levels for each bread type, said the researchers.
The authors found that pea-originated asparaginase enzyme was dependent upon the presence of potassium ions for activity and maximum activity was obtained at potassium concentrations above 20 mm. "Therefore, 20 mm KCI was added to all bread recipes based on the added water content," added the researchers.
Acrylamide analysis was performed with liquid chromatography–mass spectrometry, and other than colour, sensory properties of the breads were evaluated to determine the effects of pea flour substitution on consumer acceptability.
And consumer acceptance testing, explained the authors, was conducted on breads with participation of university staff and students. Breads were evaluated 1 day after manufacture.
The authors said that their study showed reduction of acrylamide in white wheat bread was not notable and, in fact, the addition of pea flour decreased its sensory attributes. However, they determined that acrylamide levels can be reduced by 57 per cent and 68 per cent with the addition of 5 per cent pea flour in wheat bran and whole-grain wheat breads, respectively, without any negative impact on appearance, texture and flavour.
The researchers found that while the addition of more than 5 per cent pea flour to dough might cause a more dramatic reduction of acrylamide, it could impact negatively on the rheological and sensory properties of bread. "However, 5 per cent pea flour addition can be combined with other acrylamide reducing strategies such as prolonged fermentation time."
Source: International Journal of Food Science and Technology
Published online ahead of print: doi:10.1111/j.1365-2621.2010.02370.x
Title: The effect of pea (Pisum sativum L.)-originated asparaginase on acrylamide formation in certain bread types
Authors: N. B. Tuncel, N. Yılmaz, E. Sener