The Scientific Discipline Behind The U.S. Military's Super Sandwich

From Mental Floss, Oct. 11:

The U.S.A. armed forces has a fraught history amongst food. During the Civil War, soldiers munched on tooth-cracking hardtack in addition to tabular array salt pork. By World War II, it was SPAM in addition to M&Ms. During the Cold War, the armed forces introduced the basis to survival crackers, a.k.a. Doomsday Biscuits.

But there’s e'er been ane occupation amongst close of the items on the menu: Few tasted rattling good. Hardtack regularly contained worms. Soldiers liked to call SPAM “ham that failed the physical.” The Chicago Tribune in ane lawsuit claimed that survival crackers were “better every bit weapons.”

The challenge facing battlefield rations—called “Meal, Ready-to-Eat,” or MREs—has e'er been multifaceted. The Seattle Times explains it nicely: "To qualify for MRE duty, a nutrient detail has to live able to endure years of storage inward a dank ship’s concur or a sun-baked transportation container, withstand Arctic freezes in addition to tropical monsoons, stave off assaults yesteryear insects, in addition to rest intact through a parachute airdrop or a costless autumn from 100 feet.” Taste, every bit a result, has been woefully neglected.

In 2002, researchers at the U.S.A. Army Soldier Systems Center inward Natick, Massachusetts took the starting fourth dimension tangible steps toward fixing that yesteryear concocting the world’s starting fourth dimension “Super Sandwich.” Resembling a hot pocket, the prototype—which contained fillings similar pepperoni in addition to chicken—could end upward to 2 or 3 years inward temperatures of 78 degrees without spoiling or getting soggy. (At 100 degrees, its shelf life dropped to vi months.)

For the nutrient scientists working on the problem, the enemy inward the battle to brand the Super Sandwich was water—specifically, water activity. Put simply, H2O activeness is a touchstone of how easily wet migrates from ane nutrient production to another. The higher a nutrient item's H2O activity, the to a greater extent than probable it’ll disclose moisture. The lower the H2O activity, the to a greater extent than probable it’ll absorb water.

Water activeness is a huge hurdle for foods that incorporate multiple components. Take Raisin Bran, for example: Raisins are moist in addition to convey a relatively high H2O activity. The flakes, on the other hand, are crunchy in addition to convey a depression H2O activity. Under normal circumstances, these 2 components volition merchandise moisture, amongst the raisins turning difficult in addition to the flakes soggy.

The same occupation faced the Super Sandwich....MORE