Kodiak facility refines technique for processing salmon

Developed by seafood technology specialist Chuck Crapo and a visiting scientist from Vietnam, the process is a new way of freeze-drying salmon so the fish still retains its texture and color.

In addition, the process takes only nine hours, far shorter than traditional techniques.

"Typically, freeze-drying takes several days," Crapo said. "We were trying to shorten that period of time."

He said the idea for the research came on a trip to Ketchikan, where he and others saw freeze-dried fruits and vegetables for sale.

"Why can't we produce something similar for salmon?" Crapo asked.

A lengthy series of experiments followed as Crapo, University of Alaska Fairbanks professor Alexandra Oliveira and Vietnamese scientist Duy Nguyen tested different ways of freeze-drying salmon.

To keep the salmon from turning into an unappetizing mess, they came up with a two-stage process. The first stage involves cutting the salmon into cubes, then freezing them. The frozen cubes are then put into a freeze-dryer to remove moisture.

During the second stage, the cubes are put into a dryer to remove the rest of the moisture, according to an account published in Agricultural Research magazine.

The freezing ensures the cubes keep their shape and don't shrink as much as they would in traditional freeze-drying, Crapo said.

Because freeze-drying destroys some taste, it isn't intended to replace current processing techniques. Rather, it could be used for fish currently discarded because their quality is too low to be sold economically outside Alaska.

And though the technique has proved effective in the lab and in taste tests, it isn't "ready for prime time," Crapo said.

The lab is still working on a way to lengthen the shelf life of fatty fish, which tend to turn bad more quickly than lean fish.

In addition, "Freeze-drying is a pretty energy-intensive process," Crapo said. "It takes serious vacuum pumps."

With the high cost of electricity in Alaska, that means it probably won't be an economically viable processing option anytime soon. But that might not be the case Outside, he said. There have been some inquiries from West Coast processors, and "just recently we've received inquiries from DoD," he said.

The Department of Defense laboratory in Massachusetts, he said, is particularly interested in applications for military rations.

In addition, Oliveira has received a grant through the University of Alaska's space-grant program to study freeze-dried salmon in astronaut's meals.

But while the sky is the limit for freeze-dried salmon, Crapo said earthbound options are much more likely.

"It's something you could put in soup or on salad," he said, or something like the flavor packets in cheap ramen noodles.

"And maybe there are other uses we have not thought of yet," he said.