SP-202 Aerospace Food Technology

 

FOOD DEVELOPMENT AND EXPERIENCES
 
ROBERT M. WEISS
 
The Pillsbury Company

 

[117] The food industry, in support of the special nutritional requirements of the aerospace and military programs, has conducted much research which has resulted in the evolution of many different products. I would like to share with you the results of some selected research undertaken by The Pillsbury Co. Further, I hope to encourage all of us to reevaluate our individual and collective technical information (especially spinoff technology) to determine the way in which it might be used as a baseline in solving future aerospace nutritional problems.

In 1966 The Pillsbury Co. undertook a research contract to create a rod-shaped contingency food designed to sustain a flight crew when they must remain sealed within their pressure suits. This effort resulted in the delivery of 12 different flavors of 4 different types of rod-shaped foods in the fruit, vegetable, meat-analog, and confection areas.

During the course of the research, much information was generated governing the manner in which the physical structure of food materials could be controlled. Materials from soft plastic to hard brittle and from a smooth texture to a chunky texture were developed without varying the nutritional value. Further, through the selection of special ingredients and formulas, properties such as water activity could be modified to meet desired end requirements. This effort resulted in the delivery of a low-cost, highly stable, reasonably acceptable, unique food form.

Beginning in 1962 and continuing to the present date, we have been involved in the creation of a wide variety of compressed food bars. These compressed bars, the principal components of which are natural foods, can be combined with one or more other compressed bars in variable ratios, the result being a wide, individually tailored menu array. Further, accessory flavors in the form of small cubes allow the modification of base foods to individual taste preferences. Some of the bars may be eaten both in a rehydrated form and as is, thus providing for greater texture variability.

An obvious problem of the dual-function bar is the high flavor intensity of an as-is bar as compared with that of its rehydrated counterpart. Current work has shown that flavor-contributing components can be effectively encapsulated within materials of controlled solubility in such a manner that both food forms become highly palatable. In fact, such highly seasoned foods as chile con carne are more bland in the unrehydrated form. Compressed foods provide an opportunity for achievement of extremely high nutritional densities while continuing use of a high proportion of natural foods.

Currently in excess of 5.75 Kcal/g can be provided in a hydratable bar. Because of the low bulk of this food system, an individual can be sustained at a daily caloric intake of approximately [118] 2500 cal for a period of 7 to 10 days from a food storage container no larger than an ordinary shoe box. Although this food is being primarily designed to meet military requirements, it has become a food form worthy of consideration for aerospace use. Nutritionally variable edible coatings and binders provide physical strength and crumb contamination control while, in addition, allowing the food scientist to strengthen nutritional deficiencies of the natural foods embodied within the bar.

Recently completed taste-panel evaluations have shown a high degree of acceptability for all of the 46 meal items currently under investigation. The level of acceptance, as recorded on a 9-point hedonic scale, is shown by scores of 6 or better given by more than two-thirds of the taste-panel members. The average of the mean hedonic ratings of the foods currently under evaluation is 6. 7, as compared with an average of 5.9 for the food bars developed in 1967.

We also undertook the development of a low-cost process for manufacturing bite-size foods, primarily in the bakery and cereal food areas. This effort required the application, and in some instances modification, of previously developed technologies plus the evolution of some new techniques. For example, the protein-encapsulated vegetable-oil&emdash;carbohydrate dispersion, which provided the base for rod-shaped foods, was combined with specially prepared cereal and bakery ingredients in such a manner as to create a formulated food in a recognizable "natural" form. The technique which evolved allows for the creation of a wide variety of flavors and textures in any desirable shape from a single-process system.

The material normally used for coating was used as a binder integral with the other food components. The danger of capsule contamination by broken food can therefore be greatly minimized. This nutritionally balanced food form has a caloric density in excess of 4 cal/g.

Another interesting food development project, although it was not related to human foods on the surface, at least, was the development of a primate diet in pellet form. Prior to our involvement in this ongoing program, the pellets were prepared by compacting the specified ingredients by means of standard high-pressure pelletizing techniques. Since this pellet is dispensed from a mechanical feeder not sealed from the spacecraft environment, very rigid specifications were imposed upon the manufacture of this food. Some of these specifications were as follows: (1) The pellet was 3/4 ± 0. 020 in. square, with a thickness dimension of 0.190 to 0.205 in.; (2) it must have a breaking strength in excess of 15 lb when center-loaded between knife-edge supports 1/2 in. apart, and (3) when dropped 6 in. for 120 times upon a nonresilient surface the weight loss must be less than 1 percent. All the above parameters were to be maintained throughout an ambient atmosphere spectrum of 40- to 72-percent relative humidity and 35° to 80° F.

It had been concluded after many months of effort prior to our involvement in the program that standard pelletizing techniques could not successfully meet these specifications. The current pellet is manufactured by adjusting the pH of the casein in the diet to put it in a water-dispersible form. This material is then complexed with sucrose, vegetable oil, and some of the vitamins and spray-dried in a special low-temperature drier. This processing results in a powder containing less than 2 percent moisture. When combined with the remaining vitamins and minerals in the diet, it can be pressed into dense, homogeneous pellets meeting, or exceeding, all the required [119] performance criteria. Dimensional tolerances, for example, are now maintained within 0. 005-in. variance.

My only reason for including this example is to demonstrate the opportunities available to food scientists if they look upon their ingredients as modifiable organic and inorganic chemicals rather than as material for use "as is. " I feel the major import of this kind of research is the realization that a food form readily recognizable and acceptable by the consumer can have radically modified physical characteristics without sacrificing any of the nutritional criteria.

Another interesting aspect of this work is an indication that vitamin viability has been maintained throughout the high-temperature, high-moisture storage period at original formula levels. This may be due in part to the highly impervious character of this particular food. Additional research has shown that this food can be modified (again without nutritional compromise) to have textural variations ranging from those of soft caramels to glass.

This is obviously but a part of the total food technology that has been evolved in support of special feeding needs. What then of the future ? Greater and greater demand will be placed upon the food and packaging technologists to create human food compatible with long-duration missions. We all realize the final approach will be a considerable departure from existing foods and processing techniques. Simultaneously we must create demons/ratable improvements in acceptability of these foods at their point of consumption. Some examples of possible ultimate results from our efforts are

 

(1) Extremely low-residue foods aimed at near-zero fecal loads
 
(2) Near-zero packaging requirements
 
(3) Foods containing selected microorganisms or designed to control or modify intestinal microflora in a manner to give desired end results
 
(4) Foods that may, because of their fibrous, plastic, brittle, liquid, or other physical characteristics, be used as structural components of the space vehicle prior to their use as human fuel.

 

We have heard a call for more natural food because history has shown that these foods have greater acceptability. Is not the desired end product more naturally acceptable foods ? That is a much broader concept. Manmade foods can be designed to avoid the many limitations imposed by so-called natural food. The final system will undoubtedly be a marriage of many form of human fuel. As we embark upon any program of human-fuel research and development, let us stay sufficiently broad in our approaches to stimulate real creativity. Time constraints have always been a convenient excuse for not stretching for truly new approaches. I suggest we use time and money constraints as a stimulus to our creativity and a challenge to the quality of our results.


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