Natick researchers: Vacuum microwave drying is key to new, improved rations

By Jane Benson, NSRDEC Public Affairs

Researchers at the Natick Soldier Research, Development and Engineering Center hope to acquire a vacuum microwave drying, or VMD, machine to create shelf-stable, nutritious, good-tasting foods that are also lightweight. The drying technology heats foods uniformly through a quick, gentle process. (Courtesy photo by EnWave Corporation)

NATICK, Mass. (Aug. 5, 2015) — Army scientists are looking to vacuum microwave drying, or VMD, technology to create new, quality items for rations that may also reduce the warfighter’s carrying load.

U.S. Army Natick Soldier Research, Development and Engineering Center researchers hope to acquire the pilot scale equipment to develop items that meet the stringent requirements of military rations that must be shelf stable for years in extreme climates with no access to refrigeration.

The rapid drying technology would enable the creation of lightweight, nutritious, inexpensive shelf-stable foods, including cheese, fruits, vegetables and meats. Such items could be incorporated into the following rations: Meal, Cold Weather; Food Packet, Long-Range Patrol; and Meal, Ready-to-Eat.

“Some of the conventional drying methods are not efficient,” said Dr. Tom Yang, a food technologist in NSRDEC’s Combat Feeding Directorate, or CFD.

“For example, sun drying takes a long time and is dependent upon Mother Nature. And it is not very sanitary. Another method is mechanical drying, which involves using a hot oven with hot air to remove moisture. But drying foods at a high temperature can affect quality, taste and texture. It is edible, but it can be hard like a rock. Drying foods can also take away nutrients. The food can shrink and the color can become dark. Not very appetizing.”

VMD combines vacuum and microwave technology, heating foods uniformly through a quick, gentle process.

“Since you combine vacuum technology with microwaving to remove water, you can do so at a lower temperature,” said Yang, who is part of CFD’s Food Engineering and Analysis Team. “You maintain nutrients since the rapid drying process doesn’t destroy heat-sensitive nutrients. The colors remain appetizing and the texture doesn’t become hard and brittle.”

In addition to producing higher-quality foods, the process takes less time than conventional air drying or freeze drying. Yang explained that freeze drying, which was pioneered at Natick years ago, is effective and retains good food quality but has some drawbacks.

“VMD takes freeze drying to the next level,” said Yang. “It is much less expensive and uses much less energy.”

Foods created by VMD are nutritious and pleasing to the palate. The technology also fits into NSRDEC’s mission to lighten the warfighter’s carrying load.

“It is low weight. It is very easy to eat on the move,” said Yang. “You don’t need to store it anywhere.”

The Food Engineering and Analysis Team, led by Lauren Oleksyk, hopes to obtain its own VMD machine for its Food Innovation Lab, where it will be used to create new foods for the warfighter and improve existing offerings.

“Our Soldiers deserve the best,” Yang said.
“Soldiers do so many important missions. They are under a lot of stress. They need to be well fed. Their physical and mental state needs to be in top shape. We are hoping to get a [vacuum/microwave] unit so that we can use it as a tool to try out many ingredients and recipes that we know Soldiers would like to have.”

Yang said he thinks it is important to create some favorite foods for Soldiers far away from home.

“I have an idea for a shelf-stable cheeseburger with a layer of dried cheese, a layer of dried meat, and a layer of dried bread,” Yang said. “A regular cheeseburger would be highly perishable, but this one would be shelf stable for three years. This is one of the concepts I want to explore.

“I like to explore new technology and new products. I like to see technologies that work, save money, and produce great rations that get into the hands of Soldiers.”

Editor’s note: The Natick Soldier Research, Development and Engineering Center is part of the U.S. Army Research, Development and Engineering Command, which has the mission to ensure decisive overmatch for unified land operations to empower the Army, the joint warfighter and our nation. RDECOM is a major subordinate command of the U.S. Army Materiel Command.

Originally published at on August 5, 2015.

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