How MREs Work

Chemistry Tricks

M&Ms are an example of a food product designed around the rigors of military life. The M&Ms history page describes the birth of M&Ms this way:

Who would have guessed that the idea for "M&M's"® Plain Chocolate Candies was born in the backdrop of the Spanish Civil War? Legend has it that on a trip to Spain, Forrest Mars Sr. encountered soldiers who were eating pellets of chocolate that were encased in a hard sugary coating to prevent them from melting. Inspired by this idea, Mr. Mars went back to his kitchen and invented the recipe for "M&M's"® Plain Chocolate Candies.

First sold to the public in 1941, "M&M's"® Plain Chocolate Candies became a favorite of American GIs serving in World War II. Packaged in cardboard tubes, "M&M's"® Plain Chocolate Candies were sold to the military as a convenient snack that traveled well in any climate. By the late 1940's, they became widely available to the public, who gave them an excellent reception.

Food scientists are constantly looking for ways to make prepared foods last longer, work in different climates, or taste and feel better.


For example, during the Gulf War, food engineers found a way to make chocolate bars that do not melt in desert heat like normal chocolate bars do. The technique involves emulsifiers that separate the fat in the chocolate so that, even when melted, it can not flow together to melt the bar. The chocolate does not liquefy in high heat, but it still "feels" like chocolate (rather than plastic) when you chew it. Hershey released it's version of the chocolate to the general public as Desert Bars during the first Gulf war.

Another recent triumph has been bread that does not disintegrate and does not go stale even after years on the shelf. It looks, tastes and feels like normal bread, and can even be used to make things like PB&J sandwiches, but it lasts far longer than normal bread does. It is called pouch bread because it comes sealed in a protective tri-laminate pouch like MREs do.

This article hints at some of the experiments that food engineers conducted while perfecting shelf-stable bread products for the military:

The reduction of sucrose ester (SE) [because of price] and the addition of sodium stearoyl lactylate (SSL) in pouch bread were evaluated. Water activity (Aw), pH and microbiological analysis were conducted to ensure specifications were met. Parameters such as specific volume, peak-force, L-value, and sensory were measured before during and after storage. Measured parameters indicated any changes in volume, texture, crumb color, acceptability, and relative chemical stability of the proposed emulsifier system.

A significant synergistic effect of two emulsifiers was shown. Replacing half of the SE with 0.25% SSL almost reduce the peak force (hardness) in half without significant changes in specific volume and L-value. Whereas replacing 75%SE with 0.25% SSL increased the peak force by 33%. This level also affected L-values, appearance and sensory attributes.

Research results show the beneficial, synergism of SE and SSL exist. The optimization of these emulsifiers, allows pouch bread to have an extended shelf life---now at a reduced cost. Maintaining low oxygen levels [with oxygen scavenging packets], controlling Aw [with emulsifiers] and using tri-laminated packaging give additional quality protection.

Researchers run extensive taste tests and extended feeding tests, both in the lab and in the field, to see which meals are best received. Meals that no one likes are eliminated. This research has turned up several interesting pieces of information:

  • People like variety. The original MRE program had six entrees on the menu. Today there are 24 because people eat more when there is a lot of variety.
  • "Commercial" graphics, rather than olive drab packaging, improves consumption.
  • Name brand side items (candy, chips, etc.) and a variety of "accessories" with a meal improve consumption of the rest of the meal.
  • People like the option of hot sauce regardless of what they are eating.

See the links at the end of the article for details on this sort of research.