In recent months, several warnings have been published about the potential risk of fried food for the health of millions of consumers. “Deep fried foods produce acrylamide,” said Lien Smeesters, post-doctoral researcher, B-PHOT Brussels Photonics, Vrije Universiteit Brussel. Acrylamide has been found to increase the risk of several types of cancer when given to lab animals (rats and mice) in their drinking water. The doses of acrylamide given in these studies have been as much as 1,000 to 10,000 times higher than the levels people might be exposed to in foods. It’s not clear if these results would apply to people as well, but in general it makes sense to limit human exposure to substances that cause cancer in animals.
Acrylamide doesn’t appear to be in raw foods themselves. It’s formed when certain starchy foods, such as potato products, grain products, or coffee, are cooked at high temperatures (above about 120°C). Cooking at high temperatures causes a chemical reaction between certain sugars and an amino acid (asparagine) in the food, which forms acrylamide. Cooking methods such as frying, baking, broiling, or roasting are more likely to create acrylamide, while boiling, steaming, and microwaving appear less likely to do so. Longer cooking times and cooking at higher temperatures can increase the amount of acrylamide in foods further.
In response to the concerns regarding acrylamide, food companies have implemented analytical methods for providing reliable and highly sensitive detection and quantification of acrylamide. The most common used technique is the triple Quad LC-MS-MS system, however, the major drawback is that it takes a lot of time, labor intensive and makes use of a lot of chemicals. At the Vrije Universiteit Brussel, Dr. Lien Smeesters and the B-PHOT team developed a new laser scanning technique that allows fast and accurate detection of hazardous substances such as acrylamide and aflatoxins in among others food such as potatoes, nuts, cereals or corn. “Current tests haven’t shown a correlation between their measurements and the prediction of acrylamide formation,” said Smeesters. “ We wanted to develop a method that can accurately predict which potatoes give rise to acrylamide formation.”
“With photonics, we make use of the specific light reflection at the surface versus the internal scattering,” said Smeesters. There are several types of scattering, such as specular reflection, diffuse reflection and internal scattering. The internal scattering is different for stone and potato, due to their different firmness. “First, we looked at the scattering difference between fresh and fridge-stored potatoes,” Smeesters explained. “Fresh potatoes form approximately 200-240 ppb acrylamide, whereas fridge-stored potatoes (4°C) form approximately 600-2000 ppb acrylamide.” The study showed that with increasing scattering of light in the potato correlated with increased acrylamide levels.
The next step was to go from a fundamental spectroscopic study to an acrylamide-sensing scanning set-up. “This new optical detection technique measures the risk of acrylamide formation in raw potatoes thoroughly, through a laser scanner at a speed of tons per hour,” said Smeesters. “Without the use of any chemical agents and without damaging the product itself potatoes are sorted. Potatoes with a risky composition, unsuitable for high baking temperatures, respond differently to a light measurement than ‘fries-suitable’ potatoes. In a split second, unsuitable potatoes are extracted from the production and food chain.”
Implementing of the acrylamide-precursors sensing technology will result in safer fried foods, thereby increasing the food safety of millions of people. “And there is no food waste,” conclused Smeesters. “Acrylamide does not format lower temperatures. The potatoes that are disgarded for deep frying, are still useful for other preparations, at temperatures below 120 ° C, such as, for example, mashed potatoes.