squirrel-cage blower from the bottom through the two layers of belt which act as baffles to distribute the air uniformly. Air velocity is variable from essentially 0 to 900 feet per minute, controlled by a damper on the intake side of the blower. Heat is supplied to the air by a gas burner positioned near the intake side of the blower and temperature is controlled by modulating gas flow to the burner through automatic controls. The whole equipment is enclosed in an insulated box and the amount of recirculation of heated air can be controlled between approximately 0 and 85 percent by means of an adjustable opening on the box near the burner.

After expanding, the grain was coarsely ground (or it could be left whole). Then it was placed in the heated bowl of a planetary-type mixer equipped with a wire whip or paddle and the other ingredients uniformly blended in. The formulation (at the current stage of development) is 79.5 percent bulgur, 10 percent fat (hydrogenated peanut oil, melting point 116° 118° F., iodine value 50), 10 percent dry malt extract, and 0.5 percent salt. Fat was added in a liquid state and bowl temperature maintained high enough to retain the liquid state. The malt and salt were added after dissolving them in sufficient hot water to raise bulgur moisture content to 4 to 5 percent. Mixing continued for 20 minutes to allow uniform distribution and adsorption of the additives. Any further additives such as anti-oxidants or flavoring could be added at this stage.

Textural adjustments can be made by further grinding after the materials are blended. The degree to which the material is ground alters wafer characteristics markedly. If no grinding is used, higher pressures are required to form wafers of sufficient strength; the wafers are harder to chew and the material absorbs liquids very slowly. As the proportion of fines are increased due to grinding, lower pressures are required to form wafers, crunchiness of the wafers diminishes, and the rate of absorption of liquid increases. A wide range of particle sizes, obtained by grinding after incorporation of all additives, appears most desirable. Binding is improved, a measure of crispness is retained, and liquid adjuncts are quickly immobilized because the fines absorb the liquid rapidly, yet the product is rice-like in texture.

Wafers were pressed at pressures over a range of 7500 to 10,000 psi. and at temperatures from 40° to 70° C., with residence time of approximately 2 minutes. In commercial production, residence time could probably be reduced to a few seconds by feeding preheated material to the press. These conditions will vary with formulation, melting point of fat, and moisture content. If fat alone is used as a binder the determining factor is its melting point, whereas if malt is added moisture content also must be considered.

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Each wafer contained 20 grams of material. No effort was made to determine the optimum size and shape for the wafers. They were pressed to approximately 1/3 inch thick and either 2x2 inches square or circular with 2.25-inch diameter; these are sizes and shapes common in commercially produced crackers and cookies. The circular wafers have better handling characteristics, i.e. less tendency for edges to crumble; square wafers could be packaged better and would require less cubage for storage of a given weight.

The conditions and formulations described above were based on subjective evaluations; time did not permit development or use of objective measurements related to flavor preference, wafer strength, or crumbling and chewing characteristics. A light toasting was given the grain during the expansion process to enhance the flavor. Both fat and malt were used because the combination gave desirable flavor and binding qualities. The use of both may also contribute to storage stability (see next section). Salt was added for the usual organoleptic reasons.

Storage stability

As with other cereal products, storage stability of the cereal wafers will depend on several factors. Undesirable changes over long periods of time can be minimized by proper formulation, control of moisture, use of antioxidants, proper packaging, and inert storage atmosphere. Adequate study of the effect of these variables has not been possible as yet.

Of the changes leading to deterioration, oxidative changes in the lipid fraction are most likely to occur first. Wheat contains approximately 2 percent of a highly unsaturated natural fat markedly susceptible to oxidative rancidity. Removal of this fat before or during processing offers perhaps the best possibility of eliminating or minimizing the problem. By treatment of the raw grain with dilute alkali combined with wet scouring to remove all or most of the germ, approximately 50 percent of this troublesome fat was removed.

A storage study of canned dry puffed bulgur was conducted to evaluate the effects of six different formulations, nitrogen compared with air as the package atmosphere, and three levels of storage temperature. The observations were made after the material had been stored for 47 days. This test indicated that a formulation containing both malt and fat may delay development of rancid odors. Rancidity was detected in most samples formulated with either malt or fat alone. But even after storage at 110° F., no rancid odor could be detected in any of the samples formulated with both malt and fat whether they contained antioxidant or not.

The test has not proceeded long enough to reveal any added protection that antioxidants might give. The inert storage atmosphere tended to maintain product stability.

Suggested areas for research

1. Studies of product stability and methods to extend it, including methods for defatting wheat.

2.

Development of objective measurements of wafer characteristics and, based on them, refinement of procedures

and formulations.

3. Development of lower cost methods starting from the raw grain.

Part 2. Evaluation of a Cereal-based Ration

Shelter habitability test, December 1959

Preliminary evaluation of rations based largely on cereal foods has been made possible through informal cooperation with the U.S. Naval Radiological Defense Laboratory (NRDL). Cerealbased rations have been used in occupancy tests of the NRDL experimental 100-man shelter at Parks Air Force Base in California. Details of the first test, conducted in December 1959, have been reported by Strope (47). Goldbeck and Newman of the American Institute for Research reported on psychological aspects of the test (17).

During the 14-day shelter occupancy in December 1959, three different menus were used:

1.

An austere ration of non-fat dried milk reconstituted with water and fortified with dextrimaltose and vegetable oil and supplemented with peanut candy bars.

2. Army C-rations.

3.

A cereal-based ration developed by this Laboratory.

The early status of product development precluded use of the wheat wafer described in Part 1 of this chapter. Therefore, products simulating the several menu uses anticipated for the wheat wafer and appropriate food adjuncts to round out the menus were used. The cereal-based ration was served for 3 days out of the 14; complete menus are given in Table 12. Canned boiled wheat (an experimental product of this Laboratory) was used as a breakfast cereal with milk and sugar and as main-course lunch and dinner items with hot sauces or other toppings. Fig newton cookies represented the wafers spread with a fruit topping, and cheese crackers with peanut butter represented the wafers with other flavor adjuncts.

This ration proved quite acceptable and it was easy to prepare and serve. Of the three rations used, it sustained the weight of the occupants best (all diets were planned to provide approximately 2000 cal/day/man) and it produced the fewest subjective complaints, even though it was rated less desirable than the standard Army C-rations. Many individuals on the milk-peanut diet complained of mild diarrhea, whereas those on the C-rations complained frequently of constipation.