Riding the microwave

Research into microwave technology is providing the food industry with new knowledge. New knowledge about the distribution of heat and new packaging solutions are making it possible to offer quality products for reheating in the microwave.

Contact person
Portrettbilde av Jan Thomas Rosnes
Jan Thomas Rosnes

Senior Scientist
Phone: +47 901 72 816
thomas.rosnes@nofima.no

Nofima Mat (formerly Norconserv) invited the industry to a trade day about new opportunities for food that is heated in the microwave oven. Around 20 people from the food and catering industries attended to harvest this knowledge.

No reason to hesitate

Thomas Ohlsson, now a pensioner, but formerly a researcher at SIK in Gothenburg, described the situation like this:
"There used to be far too much cook and look in this industry: the perception was that it is difficult to achieve the desired temperature. We know a lot more now about the links between technology, product and process. This gives a far greater opportunity for optimising the product. There is no reason now to sit on the fence and wait. The knowledge and the solution exist. Now we can design ovens to suit the products being heated in them," he says.

Distribution of heat

One area that has attracted a great deal of research is how heat is distributed in a microwave oven. It is a well known problem that the ovens heat up unevenly, which can lead to the food being insufficiently heated, which in turn can lead to a risk of food poisoning.

"We have carried out trials in which we have distributed a number of sensors in the food. We tried food heated both with and without a covering film and were able to see how the heat was distributed through the products. The results showed that better and more even heating was achieved when using a covering film," explains Merete Hagen Helland. She has also tried different packaging, such as plastic and aluminium. In Stavanger they have been working intensively on new methods of validating heat treatment in microwave ovens with time temperature integrators (TTIs) and have found, among other things, inherent biological markers for the effect of heat in fish.

New packaging

Microwave ovens are used for many purposes in the industry: for thawing, pasteurising, cooking, drying, sterilising and for heating up ready meals. "More and more ready meals are becoming available for microwave ovens, especially for the consumer market and catering. Using a steam valve for cooking has proved to be a good solution for ready meals. The valve is effective for double heat treatment and gives a controlled release of air and steam," says Merete Hagen Helland. Toro and Fjordland are among the producers offering meals for heating in the microwave. Over the last year Toro has brought out 10 dishes for the consumer market.

Processing Technology  

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