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This paper describes studies done with the osmotic drying and nutrient infusion of fruits and vegetables. Sensory testing was performed on the products. They were packaged, placed in storage and the percent moisture, water activity and reflectance color determined for periods up to two years of storage at 40, 70 and 100 degrees Fahrenheit. Initially, six commercial fruit products were chosen for long-term storage. Two representative products, mango-flavored apple cubes and cherries, were then prepared with infused vitamins and minerals. The commercial product, cranberries, was also studied intensively. Vegetables, potatoes, carrots and celery were also prepared with infused vitamins and minerals.

The military services have a need for low and intermediate moisture foods of good nutrition and high sensory acceptability with a reduced cost of processing. Such foods will deliver a high density of nutrients, calories, etc. Osmotic dehydration, with the aid of vacuum infusion is such a low cost operation that has many advantages. The infusion of additional nutrients, such as vitamins and minerals, into the food during the osmotic drying will further enhance the dried ration. It was determined that osmotic drying and nutrient infusion would be a viable process for the military to use in the preparation of high quality foods. The authors purchased six of their commercial items and placed them in storage so they could be studied in depth for consumer acceptability and stability. These products were made for extended shelf life with a fresh-like appearance and taste. However, they are for the commercial market which tends to require only an approximate nine-month shelf life. The military has more stringent requirements for both quality and storageability. The purpose of this study was to determine if the product met these requirements.

The feasibility of osmotic drying of various foods, pitted cherries, whole blueberries and cubed carrots, was demonstrated. The feasibility of applying the osmotically-induced migration of compounds through the membrane of food samples was also examined. The osmotic solutions included sucrose, dextrose, maltose, honey, maltodextrin and salt. Drying was accomplished at atmospheric pressure at room and boiling temperatures and under vacuum at room temperature. In some experiments, final drying was achieved in a forced air dryer.

The purpose of this project is to test the effects of different modified atmospheres and packaging systems on the shelf life extension of several foods, and their feasibility for military feeding systems. Several trials were conducted on packaging food products under modified atmospheres. Foods such as cooked boneless chicken breasts, hamburger patties and scrambled eggs were packaged under different gas mixtures, and with different packaging systems. There were also trials testing Time Temperature Indicators (TTIs), packaging equipment and local modified atmosphere packaging (MAP) producers. These studies showed that a high barrier packaging is preferable for cooked meats. Initial gas analysis for some studies showed different gas levels than what was injected such as 20% less carbon dioxide (CO2), with the gas composition remaining quite stable thereafter. There is a need to determine if reduced carbon dioxide levels or gas mixture variation is due to the packaging equipment, namely, the form-fill-sealers or gas absorption by the food and to what extent. Microbial growth was erratic during most of the studies therefore microbial correlations were inconclusive.

In order to study the effects of microwave-augmented freeze drying on food quality and drying time, frozen peas and green beans as well a raw ground beef were freeze dried both conventionally and with microwave augmentation. Instrumental quality analyses, including rehydration ration, color, and shear force, in addition to sensory tests were performed on the dried and rehydrated products. It was found the use of microwaves greatly decreases the drying time with little or no quality loss.

Minimally processed foods, which usually constitute a full meal or a significant portion of one, receive only a minimal heat processing or other preservation treatment to ensure their microbiological safety. Many of them are not sterile. They are either stored under refrigeration or frozen and require partial cooking or heating by the consumer. These products are consistent with the modern social trends of more working mothers, more single-person households, less time allocated to cooking, scattered family schedules and eating occasions, and a willingness to spend money for quality products. Typical packaging for products should withstand a challenge protocol within the temperature range of food distribution, use minimal packaging material for consumer convenience, and easily display the food products. In the military field feeding ration systems, the products closest to the minimally processed foods are the eat-on-the-move rations. They usually require no refrigeration but have to meet the needs of reduced weight, volume, and packaging waste. This paper presents current state- of-the-art packing systems for extended shelf-life chilled foods in commercial markets, for shelf stable foods, and also biodegradable/edible films for military field rations.