Scientist Dagbjørn Skipnes hopes that shaken food products with high quality will be available fo Norwegian consumers in the future.
Scientist Dagbjørn Skipnes hopes that shaken food products with high quality will be available for Norwegian consumers in the future. Photo: Kjell Merok/Nofima

A future for shaken food?

Despite excellent test results, the food industry has yet to employ the shaking method that gives food better quality and time savings in production.

This article was last updated more than two years ago.

In order to kill bacteria, many food products are heated to a certain temperature before being quickly cooled. This is done in a machine (autoclave) where the food is either stationary or rotates while being heated. The process also gives the food a long shelf life.

“The new thing now is that we can shake the food while heating it, in a so-called Shaka-autoclave. The process is much quicker, and the food comes out better in terms of both nutrient content and taste,” researcher Dagbjørn Skipnes says.

I cooperation with Orkla Foods Norge AS, Smaken av Grimstad AS and Sandanger AS, he has tested products in Nofima’s Shaka-autoclave, and Nofima has analysed the products.

The three-year project was intended to reveal which products the technique would work for, and which savings one could achieve. The project was also designed to find out how safe the method is in terms of eliminating harmful bacteria.

Better quality

“The method is unparalleled for vegetables. After the shaking process we have firm pieces with a healthy colour and good texture, and most importantly, both taste and nutrient content are preserved,” Skipnes says.

In traditional autoclave the heat penetrates the food from the outside, so when the core reaches the desired temperature and the bacteria are killed, the outer parts of the food have been overheated. In the Shaka-autoclave the food gets a much more even temperature, and one avoids the problem of parts of the product being overheated.

Peas were heated in a static autoclave to the same temperature as peas that were shaken while heating. The static heating process took ten times as long, and the colour turned yellow.

The peas to the left and in the middle were shaken and heated at 150 and 140 beats per minute respectively. The peas to the right were heated in a static autoclave to the same temperature as the others, but the heat process took ten times as long, and the colour turned yellow. Photo: Dagbjørn Skipnes/Nofima

Also soups, sauces, pasta dishes, sauerkraut and fish spreads have been tested with very positive results.

“Children’s food requires extensive heat processing, which both affects nutritional quality, colour and taste. However, with the Shaka treatment, the children’s food retains nutrients and looks much more appealing,” Skipnes says .

Researcher have also found products that are not suitable for shaking. This particularly applies to fish, where the texture is ruined by shaking, and products that require long cooking times to obtain the right taste, such as stews.

“We tried a fish soup with pieces of fish, and the pieces broke apart. However, this soup proved to be very popular among children. We named it ‘Children’s fish soup,’” the researcher smiles.

When the researchers subsequently reduced the shaking speed, they saw that heating was almost as fast, without harm to the fish pieces.

Better products and new concepts

The companies tested product they already have in their portfolios. A number of the products rated better in terms of taste, texture and nutritional content compared to products that had been through an ordinary autoclave.

A new concept the researchers developed was cooking porridge in the autoclave. This kills two birds with one stone in that both the cooking and sterilization process are achieved simultaneously. The same was also successfully achieved with sauerkraut.

“The new technology inspires the development of completely new concepts, but also provides the opportunity to enhance products that previously have not been relevant to sterilize. For example, we can imaging a comeback for canned apples and plums,” Skipnes says.

Saves time, energy and space

The Shaka method also provides a much more continuous production process. The time it takes to sterilize the food is shortened by between 60 and 93%, depending on the product. When the process is faster, the food producer will also save energy, and can make do with less storage space.

“We achieve a much more continuous production and more intensive exploitation of space,” Skipnes says.

With great benefits both in terms of quality and production, it is therefore relevant to aks why no Norwegian food industry businesses have started to use the Shaka technology.

Documented safety

Several business have awaited documentation on how safe the method is in terms of eliminating harmful bacteria. Senior research fellow Baris Ates has worked on the issue for the past three years in connection with his doctoral thesis. In several experiments he added Listeria and other harmful bacteria to fish soup. After the Shaka treatment, the bacteria were inactivated.

PhD student Baris Ates added Listeria to fish soup to test if they would be killed in the shaka autoclave. He documented that the method is just as safe as ordinary autoclaves.

PhD student Baris Ates added Listeria to fish soup to test if they would be killed in the shaka autoclave. He documented that the method is just as safe as ordinary autoclaves. Photo: Lidunn M. Boge/Nofima

His work has now documented that the same methods for calculating safe processes in ordinary autoclaves also work for the Shaka autoclave.

Still on the fence

A Shaka autoclave is a major investment that will be demanding and may be out of the question for small food producers. Larger producers have other factors to consider.

Smaken av Grimstad was one of the companies that tested its products at Nofima. Purchaser Ole Bjerkås is unsure of whether this is the technology of the future.

“The Shaka autoclaves are smaller than the ordinary ones, so we would have to process smaller lots at a time. And of course there is the question of price. Our new owners have decided that we will go for ordinary autoclaves. And because our products achieved only average results after storage, we can’t really see the great benefit,” Bjerkås says.

Orkla Foods Norge experienced that the Shaka treatment minimizes or completely prevents the brown burn that is often seen at the bottom of cans. Other products that easily clot, had a smoother texture.

“Several of the tested products had a clear improvement in freshness through movement in the autoclave. However, as some raw materials don’t cope well with the movement, we are unable to use such an autoclave with all of our products. That would require us to have several autoclave technologies in order to produce a wide range of products,” says Mona Storødegård, product developer with Orkla Foods.

Even though production of a wide range of different products may preclude investing in the equipment, Storødegård is optimistic on behalf of the Shaka technology.

“I believe a gentler processing of foods will become more important to consumers in the future. Shaka processing of products may be a method to accommodate this. We believe the products made with the Shaka technology could have enhanced quality and provide consumers with a greater sense of freshness, resulting in an even better food experience.

Peering into the crystal ball

At Nofima researchers are continuing work in testing, documenting and developing knowledge on Shaka technology and how it may improve food products. It remains to be seen whether any of these will make it to the supermarket shelves.

“A possible scenario is that a large company introduces a series of completely new products that no one has ever seen before. This may nudge other producers into action,” Skipnes says.

“Another possibility is that foreign producers enter the market with products that have been processed in this manner. There are several Shaka autoclaves at both French and American producers.

Nofima has also noted great interest from foreign businesses who recognize the benefit of the Shaka technology. Several foreign companies have also tested their products at Nofima.

 Processing technology  

Related content

  • News