Optimal storage involves temperature, lighting, humidity and air quality. Researcher Pia Heltoft Thomsen is leading two projects that will contribute to better potato quality, profitability and less food waste. The aim is to guarantee the industry access to good, Norwegian potatoes throughout the year.
Good year-round potato quality requires the potatoes that arrive for storage to be of good quality. This requires careful harvest that reduces the risk of damage, and that the harvesting takes place in dry and breezy weather, and not when it is too cold and wet.
The first weeks in storage are important. The potatoes must be ventilated well and go through a wound healing process to cure damages and wounded tissue. It is then important that the temperature is lowered gradually. Drying and wound healing requires a temperature of approx. 12 degrees and good ventilation to remove excess heat, water and CO2. How quickly potatoes need to be cooled depends on what they will be used for. Potatoes for cooking which must have a nice skin, should be dried and cooled quickly to avoid silver scurf and black spots.
Potatoes for crisps must not be stored below 7 degrees. This is to prevent the starch being converted into sugar. Too much sugar content can result in carcinogenic acrylamide in crisps and french fries. On the other hand, potatoes for cooking can be stored at approx. 4 degrees. The low temperature provides a longer shelf life and prevents sprouting. However, when storing below 3–4 degrees the potato can take on a slightly sweet taste. Because potatoes used for deep frying must not be stored too cold, it can be difficult to prevent them from sprouting.
In the Antigro project, researchers are testing various anti-sprouting agents, including mint and orange oils. They see good effects from the new agents on the market, but it is important to learn how to use them correctly. Under Norwegian conditions we need fewer treatments and lower doses than other countries in Europe.
This project will focus on development of new, robust and sustainable strategies for long-time storage of frying potatoes, as an alternative to the previously used sprout suppressant which is no longer allowed. The strategies will be adapted to the various types of stores and potato qualities used in Norway.
Storage conditions for processing potatoes and reducing acrylamide levels during storage are the focus areas in this project.