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30.03.2005

New dehydration method ensures inexpensiv granulated food of high quality

The Norwegian company Dtech AS - a spin-off of SINTEF and NTNU - is in the process of building a large factory on the basis of the results obtained by the three scientists.

The new plant will supply the international food industry with dried maize and dried peas - ingredients which will end up in dried soups and powdered casserole dishes all over the world.

High quality at low price

In their bags, the maize and peas are small and dry. Once water has been added in the users’ cooking pots, they become fresh and juicy again. In terms of the taste, aroma and colour of the end-products, the new technology approaches the quality of vacuum freeze-drying - the Rolls Royce of dehydration technology. But the new technology is much less expensive.

International trend

The growing use of powdered foods is due to the fact that many people wish to put less time into preparing meals. We have gone into this field with the aim of giving people the best possible ingredients in bags of granulated food”, says Professor Ingvald Strømmen, one of the fathers of the new technology.

Well-fed adventurers

During the 16 years since the invention of the process, the scientists have tested the dehydration method on a wide range of raw materials. Two students who crossed Greenland on skis in 2004 used one of the company’s products in their canteens. They added water to minced beef that had been browned and then dried before they set off on their journey.

“It all worked perfectly”, they said when they returned home.

How the dehydration method works

The drying system developed in Norway is filled with frozen raw materials. The process of dehydration starts in a chamber kept at sub-zero temperatures, which makes the food highly porous and gives it good capacity to absorb water again in the cooking pot. The process is completed in a chamber at a temperature kept above freezing point, in order to reduce the drying time.

The combination of high quality and low price sounds like an impossibility. Nevertheless, the Norwegian scientists managed it, by combining two technologies.

Fluidized bed: The particles to be dried are suspended in a vertical current of gas. This dehydrates them on all sides at once, shortening the drying time and increasing the capacity of the system.

Air treatment in heat pump: The drying air circulates in a closed loop connected to a heat pump. The air acquires the correct properties for drying when it meets the hot side of the heat pump. It is then dehydrated again as it passes through the heat pump’s cold side, reducing energy consumption.

Helge Rosvold | Source: alphagalileo
Further information: www.sintef.no/content/page1____4332.aspx
www.forskningsradet.no/

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