Package Design | packagedesignmag.com

(June 2005) posted on Tue Dec 15, 2009

By Ron Romanik

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Everyone knows that steam cooking retains the most vitamins and nutrients in vegetables, and many also prefer the fresher tasting steamed veggies. Now consumers can have the convenience of frozen vegetables — and other meals — with the health and taste of steam cooking, and with a reduced cooking time as well.

The technology behind Healthy Fx™ Microwave Products by QuickWave International Corp. is easy to explain but harder to imagine. These plastic pouches have microscopic built-in vents manufactured in the film. The vents are closed at most temperatures and pressures. As pressure builds from steam inside the pouch during cooking, the pouch expands and the tiny vents, or pores, open enough to allow excess steam out, but not too much so the pouch collapses. As long as there is moisture inside that is being heated to steam, the pouch remains expanded, the contents continue to cook, and the excess steam escapes.

Vegetables are the most obvious first application of this technology, but the pouches are versatile enough for most foods, from meats to soup. The first commercial applications are for vegetables in the U.S. and for sticky rice and vegetables in Taiwan. Clear pouches for home use are also available, and they resemble a normal large zip-lock bag. These pouches are also reusable after a quick rinse, as long as the zipper can achieve a tight seal.

When using a commercial Healthy Fx pouch of frozen vegetables, the veggies are cooked in two ways, so cooking time is less than normal — up to 50% less. While the food is still cold, microwaves penetrate deep into the food and heat the moisture there to steam cook from the inside out. Outside-in pressure cooking occurs as the the pouch retains enough steam and pressure to cook the food thoroughly.

Shirley Cox, the North America sales manager for QuickWave International, explains the advantages of this mini-pressure-cooker. "Because the bulk of the pressure is retained, there is more moisture, vitamin, and nutrient retention," says Cox. The film is totally FDA compliant for use with all foods and manufactured from non-toxic and odorless materials. The trick with all the pouches is that the whole pouch does not vent, only a "strip" positioned on the "up" side of the bag. Therefore, it is possible to cook wet foods — even soup — as long as the venting strip is above the level of the liquid.

For mass commercial applications, the material is available in flat or stand-up zippered pouches or roll stock. The film can accept up to eight colors — offset or rotogravure, surface or reverse — without affecting the venting action. The five layers of the film are typically two tie layers separating two 12-µm PET layers and a 30-µm CPP layer. The first PET layer can be substituted with other barrier films such as nylon, EVAL, etc. The material is also available in "lidding" stock for other microwave tray, dish, or cup-size applications. All of QuickWave's products have a temperature range from -40° F to 425° F (-40° C to 218° C). For more information, visit www.quickwaveintl.com.