Fresh deep-fried crisps from Frosta in Trøndelag. Probably the healthiest crisps on the planet. Photo: Lars Bugge Aarset

The healthiest crisps on the planet

Researchers have now found out how to stop the formation of harmful acrylamides when deep-frying potatoes to make crisps.

Frying potatoes causes the formation of harmful chemicals called acrylamides. The acrylamide content in potato crisps is influenced by factors such as the potatoes themselves, storage conditions and the heat treatment process. Researchers have been looking into acrylamides together with the food packing company Produsentpakkeriet in Frosta, north-east of Trondheim, Norway.

“Here we face an additional challenge because colder growth conditions often mean that less mature potatoes are used to make crisps”, says researcher Solveig Uglem at SINTEF, who has been heading the research team. “Less mature potatoes contain more sugar, and this can lead to a higher acrylamide content in the crisps that we make from them”, she says.

Frosta in Trøndelag is in the heart of ‘potato country’. The climate here is relatively cold, and this places demands on potato storage, which has to be just right in order to avoid the formation of acrylamides during frying or baking. Photo: Lykt Foto og Film

Reducing food waste and boosting quality

According to the research team, this project has provided us with new knowledge about the best ways of storing potatoes in order to reduce food waste. It has shown us how to achieve  optimum crisp quality and minimise the risk of acrylamide formation.

The results demonstrate that three key factors are involved:

  • Use of the right kind of potato
  • Achieving the correct maturity before harvesting
  • Achieving a correct and tailored storage temperature

As part of a three-year study, the researchers have also been looking into the use of simple methods of measuring the sugar content of potatoes. Such measurements, taken both before and after harvesting and while the potatoes are in storage, are important for ensuring that sugar levels are sufficiently low to enable the potatoes to be made into crisps.

The team discovered that measurements of sucrose and aspartic acid contents in potatoes offered the best indicators of the acrylamide levels that crisps will obtain after deep frying.

“However, this method is slow and requires the use of expensive instruments”, says Erlend Indergård, who has been participating in the project. “We’ve found that measuring glucose concentrations using a blood sugar meter that anyone can purchase at a local pharmacy offers a quicker and more accessible means of getting an indication of whether a potato’s sugar content is too high”, he says.

Thumbs up from farmers

So far, the method has been well received by potato growers. By measuring the glucose content, they can get an indication as to whether or not their potatoes are right for harvesting. It is both unsustainable, and can result in major financial loss, if a batch of potatoes has to be rejected because sugar levels are too high. Potato growers should thus be encouraged to keep track of the glucose content in their crop both immediately after harvesting and during storage. This will enable them to take action if they observe any changes in quality.