Preservation of foods always has been one of the primary reasons for food processing, and dehydration has been one of the key means for achieving that. From solar heat to freeze drying to salt or sugar infusion, many methods have been employed to remove water from food products, especially fruits and vegetables. All have advantages and disadvantages.
Nearly 15 years ago, Tim Durance, a professor at the University of British Columbia, began experimenting with microwave energy as a means to evaporate the water out of fruits and vegetables. He employed radiant energy vacuum (REV) technology, which uses a combination of vacuum pressure and microwave heating to dehydrate food while maintaining its nutrients. He coined the term nutraREV for his process.
The resulting products have rich textures, concentrated flavors and excellent nutritional – and environmental – benefits, according to the company. The dehydrated products have similar or improved post-dehydration survival of live organisms or nutrients compared with freeze-dried products, with similar or better shelf life.
Perhaps more importantly nowadays, the process involves lower energy costs, lower capital costs and significantly faster processing times. Altogether, the nutraREV process uses 30 percent less energy and reduces capital costs by 80 percent, according to company figures.
While remaining associated with the university, Durance started a company, EnWave Corp. (www.enwave.net), in 1996 to commercialize the technology. “Like all pioneering technologies, nutraREV has followed a lengthy path to development,” says Jennifer Thompson, vice president of corporate development. But its first commercial scale machine recently was installed.
EnWave selected blueberries as its first target market for the nutraREV technology, both because they make an ideal starting point for this technology and because of the wide availability in the company’s Vancouver home area. Cal-San Enterprises, a Richmond, British Columbia, blueberry grower, helped with the testing and fine-tuning of the machine. Together, they produced blueberries with a wide variety of moisture contents – from arid, crunchy ones to semimoist raisin-like ones, plus some puffed berries.
The ability to dial-in a desired moisture content and to puff the berries “is something freeze drying just can’t do,” says Thompson. “And we were able to produce high volumes of puffed berries with just half the staff needed for a comparable freeze drying operation.”
Cal-San bought EnWave’s first commercial-scale machine and is exploring the market for dried blueberries in Asia, as well as North American ingredient markets for snack foods, energy bars and breakfast cereals. EnWave on its own is pursuing North American markets for tomatoes, potatoes, onions, herbs, cranberries, strawberries and sour cherries. One EnWave prototype, the PowderREV process, can be used on food cultures and fine biochemicals.