Washing and soaking potatoes at home prior to frying them reduces the risk of acylamide formation says a new study, shifting focus away from measures to be taken by food manufacturers.
The researchers were led by Dr Rachel Burch from Leatherhead Food International and the study features in this month's Journal of the Science of Food and Agriculture.
It uncovered methods for the public to reduce asparagines in French fries, thereby lessening the likelihood of acrlyamide being formed, and begs investigation into whether such a simple technique could be used by manufacturers. It also emphasised that the problem is not just one for the industry.
Acrylamide is a carcinogen that is created when starchy foods are baked, roasted, fried or toasted. 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, with the focus always being on ways the industry can prevent the carcinogen from being formed.
The potatoes were stored at 12 degrees Celsius and studied after six weeks, 16 weeks and 34 weeks.
For the 30 pre-treated samples, potatoes were washed for 30 seconds under running tap water and then soaked in water. All potatoes were analysed after 30 minutes of soaking. The potatoes stored for six weeks were also analysed after two hours of soaking.
Control French fries were prepared and cooked with no pre-treatment.
Researchers found that all pre-treatments led to lower levels of acrylamide. At the first sampling point after six weeks, acrylamide levels were significantly different between the control and soaked French fries for Maris Piper and Desiree samples. Washed Desiree samples were also significantly lower in acrylamide than the control.
At sampling point two (16 weeks), acrylamide concentrations were significantly lower in the French fries cooked after soaking in water compared with the control.
Similar results were seen after 34 weeks. On average, acrylamide levels were reduced by 30 per cent in soaked samples.
The report's authors said: "It has been reported that blanching or soaking removes sugars from raw potato pieces. Therefore it is assumed that the pre-treatments used here have removed acrylamide precursors from the raw potato, leading to a reduction in acrylamide concentration.
"It has also been reported that standing water extracts less starch from the cut surface of the potato than running water, and that acrylamide levels were lower when the starch was not removed. This therefore may be another factor to explain the lower acrylamide levels found here."
Other ways to cut acrylamide risk
Studies are beginning to emerge that show antioxidants may reduce acrylamide levels, with evidence available that ascorbic acid (vitamin C), and rosemary extracts reportedly reducing levels of the potential carcinogen in breakfast cereals, crackers, and even olive oil used for frying.
Indeed, studies have already shown that the likes of citric, lactic, tartaric, and hydrochloric acids may reduce the levels of acrylamide in a variety of bakery products, including baked corn chips, semi-finished biscuits and crackers.
Another growing area of interest is enzymes. Asparaginase can be employed to turn asparagine into aspartic acid, which prevents acrylamide formation in the Maillard reaction.
At the tail-end of 2007 the Confederation of the Food and Drink Industries of the EU (CIAA) included asparaginase in the new version of its Acrylamide Toolbox, a move seen to validation the efforts of companies that have developed commercial solutions using the acrylamide-reducing enzyme.
Source: Journal of the Science of Food and Agriculture
Published online ahead of print, doi: 10.1002/jsfa.3179
"The effects of low-temperature potato storage and washing and soaking pre-treatments on the acrylamide content of French fries"
Authors: Rachel S Burch, Agnieszka Trzesicka, Matthew Clarke, J Stephen Elmore and Nina Webber