Acrylamide formation does not occur in an emulsion below the temperature of 115oC, and suggests that phenolic compounds such as trolox and gallic acid could work to reduce formation by up to 70 per cent, according to a study, published in Food Chemistry.
The researchers, based at University of Ioannina, Greece, and the University of Napoli ‘‘Federico II”, Italy, concluded that: “The addition of standard phenolic compounds,containing hydroxyl phenyl groups in an emulsion model system resulted in reduction of acrylamide content.”
Acrylamide is a suspected carcinogen that is formed by a heat-induced reaction between sugar and asparagine. 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 reported that unexpectedly high levels of acrylamide, increased cancer incidence in laboratory rats.
Epidemiological studies have since reported that everyday exposure to acrylamide from food substances is too low to be of carcinogenic concern - however in March 2010 the European Chemical Agency added the compound to its list of ‘substances of very high concern’.
Antioxidants have been suggested as a plausible mechanism to inhibit acrylamide formation in foods, with antioxidants such as phenolic compounds, flavonoids, and vitamins reported to inhibit formation. Some of the compounds linked with a reduction in acrylamide formation include hydrocolloids, fruit extracts, proline, and taurine.
Acrylamide is generally formed at temperatures higher than 120oC, with previous research demonstrating the influence of temperature on acrylamide formation indicating that formation increased with frying and baking temperatures.
The new research investigated the formation of acrylamide in an emulsion system for the first time, whilst studying the effects of phenolic compounds on acrylamide formation in the system.
Temperature was observed to be a key factor for acrylamide formation – with negligible amounts formed at temperatures lower than 115oC.
Given that acrylamide formation was very low at 115oC, a temperature of 125oC was chosen to examine the effects of phenolic compounds (trolox, ferulic acid, gallic acid, protocatechuic acid and caffeic acid) on acrylamide formation.
The addition of standard phenolic compounds, containing hydroxyl phenyl groups in to the emulsion model resulted in reduction of acrylamide content, with the research showing such compounds to be effective in acrylamide mitigation.
Reduction in acrylamide formation was observed to be at its best during the initial stage of heating – where it was seen to reach up to 70 per cent for trolox, gallic acid and protocatechuic acid and up to 50 per cent for ferulic and caffeic acid.
Such reductions are not as great as those seen with commercial approaches, such as enzymes. Products from both Novozymes and DSM are said to be able to reduce acrylamide formation by up to 90 per cent.
Source: Food chemistry
Published online ahead of print, doi:10.1016/j.foodchem.2010.06.025
“Effect of standard phenolic compounds and olive oil phenolic extracts on acrylamide formation in an emulsion system”
Authors: K. Kotsiou, M. Tasioula-Margari, E. Capuano, V. Fogliano