New High-Pressure Preservation Process
March 25, 2005
March 25, 2005 -- They talk of orange juice that, after 12 weeks of refrigeration, tastes as good as fresh, of TV dinners that "deliver a gourmet restaurant experience," of bananas that don't turn black and of scrambled eggs for soldiers' rations that taste as if they were just cooked.
The secret, they believe, is a costly new high-pressure preservation technology. The process, which uses pressure equal to the weight of two elephants standing on a dime, takes about 10 minutes. Vacuum-packaged food is dunked in tanks of water, the tanks are sealed, and then more water is pumped in. As the water's pressure rises, compressing the food, it kills bacteria, enzymes and molds by breaking their molecular structures and popping their cell walls like blisters. Once the pressure's off, the food returns to its original volume and appearance.
Why isn't the food pulverized? It's all in the physics: As long as pressure is uniform on all surfaces of an object, it won't distort it. (Think of a grape inside a sealed water bottle. No matter how hard the bottle is squeezed, it doesn't crush the grape.)
High-pressure preservation has its downsides, however. It's too expensive for many products and still requires refrigeration. It doesn't work well on vegetables and discolors foods if the pressure is too high.
Story reprinted from SunHerald.com