From the beginning of time, the history of man has been his struggle to obtain food. After many thousands of years, this is still a major problem which confronts the peoples of the earth. Although much food is available on earth, a great deal never benefits mankind because of deterioration and spoilage. Various kinds of spoilage cause a million tons of grain to be wasted each year. Man has learned to control and overcome some of these destructive forced through a variety of methods of food preservation. Some forms of preservation such as drying, salting, and so forth, probably have been known since the beginning of civilization. The most ancient method of food preservation, drying, was copied from nature. Early man gathered dried fruits, berries, nuts, legumes, and grains which had matured and dried on the plants. Later they used their shelters to dry food, and pre-Columbus American Indians used the heat from their fires. However, it was not until about the latter part of the eighteenth century that a hot air dehydration room was used. Much of the drying done for modern consumers is in the form of dehydration, which means artificially dried. About the same time that dehydration came into being, Nicholas Appert began work on another process of preserving food, which came to be known as canning. He received an award from Napoleon when he proved that food heated in sealed containers would not spoil if the containers were not reopened or the seal was not broken. For half a century there was no correct explanation for the success of this process until Pasteur discovered that microscopic growth caused food to spoil. It then became clear that Appert had destroyed micro-organisms by heat, and excluded their re-entry by sealing the containers. The invention of a pressure steam retort, social legislation of the Food and Drug Act, use of the common "sanitary" tin can, and research devoted to the study of nutrients in relation to the canning process have all aided significantly in creating our modern canning industry. Desrosier (7) has aptly said that food preservation practices prior to the discovery of canning were copied from nature. Canning, which has no counterpart in nature, has changed the eating habits of the western world. Although freezing was used as a method of preserving foods for centuries, the invention of a successful refrigerator in the late 1800's marked the beginning of the vast field of the modern method of refrigeration and freezing. Fish was frozen commercially as early as 1880; meats, in 1891; fruits, in 1905; and vegetables, in 1929. However, int he 1930's when modern homes contained a refrigerator, frozen foods began to find their place in commerce. It was not until 1940 that freezing assumed its rightful place as a means of preservation. To preserve foods as nearly as possible in their natural state has long been an aim of man. Each method of preservation has obvious advantages, but not one has wholly accomplished this aim. If a method could be found that preserved food without marked change in its natural characteristics, it would mean man was close to achieving his goal. Fruits and vegetables, which are very perishable, make up 40 percent of the total food consumption. Twenty-five to 50 percent of the fruits and vegetables produced to be eaten fresh, spoil before they can be consumed (45). A new method of food preservation was made possible in 1945 when the Congress of the United States passed the Atomic Energy Act. Several divisions of the Atomic Energy Commission were concerned with the application of the peaceful uses of atomic energy. In 1953, considerable research on radiation preservation of food was started on a large scale. Subjecting food to ionizing radiation has been accepted by many as an effective means of preservation. Because of the many complex problems associated with radiation sterilization, preservation by this means is not as feasible at this time as that accomplished by the low doses of radiation for pasteurization. However, there are a number of areas in these low dose treatments which show great promise for use of radiation processing of foods. 1. Conservation of grain and certain packaged products by the destruction of insect infestation. 2. The inhibition of sprouting in potatoes and other root crops. 3. The destruction of trichinae in pork and pork products. 4. The inactivation of Salmonella in egg products. 5. The extension of shelf-life of fresh fruits and vegetables, cut meats, and fresh fish. The first four areas are approaching the stage at which commercial exploitation might be considered. However, considerable research must still be pursued toward the improvement of certain radiation-treated fresh foods in regard to wholesomeness, nutritive value, color, texture, flavor, and odor. The studies presented in this thesis were conducted on the acceptability and refrigerated-life of strawberries, and sweet cherries in relation to gamma radiation dose, variety and maturity of crops and physical changes.

The rapid growth of the dairy industry which began in the latter half of the nineteenth century necessitated the development of chemical tests for determining the composition of dairy products. Chemists devoted much study and labor in devising methods which would be both accurate and rapid. As a result of these researches a large number of tests were developed. Many of the methods possessed considerable merit and a few were so satisfactory that the rest did not come into general use. The basic principles of all the tests now in use were discovered between 1880 and 1890.

Purified prorennin appeared to be homogeneous when subjected to chromatography on a Diethylaminoethyl-cellulose and to electrophoreses in starch-urea-gel. Crystalline rennin was heterogeneous, and was resolved into six components when analyzed electrophoretically. When crystalline rennin was chromatographed on a column of Diethylaminoethyl-cellulose two distinguishable peaks were observed which corresponded to B- and C-rennin. Unlike crystalline rennin, rennin freshly activated at pH 2.0 or 5.0 was essentially homogeneous. Rennin resulting from activation at pH 2.0 and 5.0 appeared to be different. Rennin activated at pH 5.0 was eluted faster from Diethylaminoethyl-cellulose column, and moved slightly faster in starch-urea-gel electrophoresis, than rennin activated at pH 2.0. Amino acid analysis showed that rennin activated at pH 2.0 had more arginine and less proline than that activated at pH 5.0. This could be accounted for the differences in chromatographic and electrophoretic behavior of these rennins. Crystalline rennin exhibited more resistance to urea denaturation than prorennin. This suggested a fundamental difference in their secondary or (and) tertiary structures. It also showed the importance of intramolecular H-bonding for enzyme activity. An increase in crystalline rennin components was accompanied its prolonged exposure to 6 M urea. This was not the case with prorennin.

Broiling is cooking tender cuts of meat by radiant heat from hot coals, a gas flame, or an electric element. Steaks and chops for broiling are from 1 to 2 inches thick. Broiling as a method of cooking mat is not new, but the directions for the process are the result of individual trial and error testing and are often in conflict. Current interest in indoor and outdoor broiling, particularly in Western United States, emphasizes the need for better information. There is no measuring device for surface heat during broiling and thus little research on the relationship of surface temperature, degree of doneness and cooking time. Little has been done to investigate the effect of a change in rate of heat transfer on the physical and chemical reactions which occur during broiling. Although some work has been done on the effects of different cooking methods on weight losses, tenderness, palatability, and thiamine content of beef, no reports were found relating cut of meat, temperature at the surface of the mat, and degree of doneness to other factors during broiling. The existing literature contained relatively little information on changes produced in broiled beef. Most of the data available were indefinite, lacking precise information regarding time and temperature. Timetables for broiling, like roasting, varied in directions given and frequently stated the time of cooking in minutes per pound. At best this can serve only as a poor guide because the amount of fat and bone present, the state of the meat, whether solid or ground, the amount of connective tissue present, and the thickness of the meat influence the rate of heat penetration. This initial study was conducted on beef using charcoal as the source of heat, since the heat of the charcoal could be controlled at different temperatures. A high, medium and low temperature were used for cooking and the meat was cooked to three degrees of doneness (rare, medium and well-done). In this research a potentiometer devised by Taylor Instrument Company to measure the temperature at the surfaces of the meat and internally was used. Thus it was possible to accurately measure the temperature. An experimental model of a coil-type thermometer was also made by Taylor Instrument Company and its use offered, for the first time, the possibility of determining the temperature at the surface of the meat. The purpose of this study was to investigate the relationship of surface temperature during broiling to stage of doneness and to cooking time on the following factors in broiled sirloin steaks: thiamine retention, soluble protein content, weight loss, moisture retention, changes in tenderness, juiciness and flavor. It was hoped that the findings might be of use in the development of a thermometer to be used for broiling much as oven and meat thermometers are used now for roasting meats. Also, an attempt was made to develop time-temperature charts for use in broiling.

Venison meat has a characteristic flavor which is acceptable if mild but some venison has a strong and objectionable flavor. The subject is of practical importance where deer is hunted as sport and for food. Each year in the State of Utah, over 180,000 hunters go in search of deer and over 130,000 animals are killed. This contributes about 10 1/2 million dollars to the economy of the state from licenses, lodging, transportation and other expenses of hunting. The problem is not only important in Utah but also in the U.S.A. and other parts of the world where venison is available and included in the diet. Little work has been done in the study of the components which give venison its characteristic flavor. Today, flavor chemistry is relatively a new field. Kurtz (1959) defines flavor as complex sensations resulting from the stimulation of the senses of odor, taste, feel, and sometimes vision and audition. Gas-liquid chromatography is a powerful tool to a flavor chemist. The first classical paper describing both the gas-liquid partition technique and a relatively simple apparatus for resolving the aliphatic acids was published int he year 19552 by James and Martin. In 1956 the number of published papers was approximately 200. By 1960, the use of this technique had increased tremendously as evidenced by the fact that the number of publications were then about 1700. Application of this technique has resulted in a number of papers on volatile compounds in various foods. The ultimate aim of studying these volatiles is to make it possible to improve the flavor of food products. The editor of Food Technology (Stewart, 1963) has stated that flavor is a challenge to a food technologist and that he has to answer such questions as: 1. Does the volatile compound which has been identified int eh sample have sensory properties 2. If so, what is its nature? 3. What combinations of components result in the sensory properties typical of the original product from which they were derived? Only after the studies have been made will we know the significance of these volatile compounds. The present study is a second phase in a project on investigation of venison quality and palatability being made under a federal aid project (W-97-R0 through the Utah Department of Fish and Game. These phases include (a) the effects of field care, aging and cooking on the venison meats and (b) flavor components, their presence, distribution and factors affecting the amounts of these components. In the previous work on item (b) above, a comparative study of water soluble flavor precursors of venison and beef was made (Reddy, 1964). The present study deals with the nature of volatile compounds in cooked venison samples and determination of differences in venison flavor in animals of different ages, sexes, and season of kill. Evaluation of flavor was also made by a panel of judges.

Eleven strains of lactic cultures were used to determine their effectiveness in different bulk culture media for the manufacture of Cottage cheese. The acid phosphate-treated whey-based medium (APWM) made from Cottage cheese whey was found to be as effective as sweet phosphate-treated whey-based medium (PWM) made from Swiss cheese whey in supporting the development of lactic cultures. The relative activity of cultures in APWM with pH control was higher than phage inhibitory medium and nonfat dry milk without pH control. APWM was used successfully in the manufacture of Cottage cheese. Greater reliability and shorter cutting time resulted, and the product was comparable to those made with conventional media. More lactose was utilized when pH control was involved. More acid was also produced at a greater rate with an implied reduction in growth curve lag phase and an increase in maximum viable cells in the maximum stationary phase.

According to the 1964 census the production and sale of livestock provided a major source of income in the state of Utah. Twenty-three of the state's twenty-nine counties received more than 40 percent of their total farming income from livestock sales in 1959. According to Taylor (1965) this is expected to increase even more. In studying the economic sources within Utah, it becomes evident that many of the state's farmers and ranchers depend heavily on the sale of livestock for their livelihood. Upon observing this fact, Taylor (1965) states that farm income will depend just as heavily on the sale of livestock as in the past. He suggests one reason for this increase is because beef cattle have been replacing dairy herds and sheep since 1945. For example, between 1962-64 dairy cattle decreased by 38,000 head. The chief agricultural export items in Utah are beef and lamb in carcass form. The meat packing plants process 250 million pounds of red meat annually. Of this 250 million pounds, 209 million pounds are consumed in Utah and about 41 million pounds are exported to other states. In recent years much study and research have been done on tenderness of beef. The quality and consumption of less tender cuts of beef, which are also less expensive, would be increased if a method of cooking could be used to attain this tenderness. Hiner (1955) points out that "tenderness in beef is a function of many interrelated factors namely: breeding, feeding, management, age, period of aging of raw meat, presence of collagenous and elastic fibers, the method of cooking the meat and probably many others." Recent studies have shown that low temperature cooking increases the tenderness of beef. Cover (1937 and 1943) reports that roasts cooked at 176 F were "very tender" but dry as compared with those roasted at 257 F. She explains that the "tenderness is due to the longer cooking time rather than the oven temperature." This may be true with quantity roasts but more work needs to be done on dry-roasting at the standard oven temperature which is from 300 to 325 F. Nielsen and Hall's (1965) study shows that blade roasts were more tender roasted at 225 F than at 325 F and were equally as tender as those braised. Many housewives no longer have time to roast a piece of meat for two or three hours just before dinner. If they could put the meat in the oven at a lower temperature before leaving for work in the morning and take it out in time for dinner at night; having a comparable roast in tenderness, juiciness, and flavor; their cooking problem would be somewhat simplified. The Animal Science Department of Utah State University has been experimenting with breeding Hereford and Hereford-Shorthorn crosses. One phase of their experiment is concerned with tenderness. The Food and Nutrition Department agreed to conduct tests for tenderness, juiciness, and flavor and acceptability on standing rib roasts cooked at 325 F. Through the courtesy of the Animal Science Department adjacent standing rib roasts and adjacent paired chuck roasts were furnished and were dry-roasted at 225 F and 325 F. This was done to compare tender and less tender cuts of beef roasted at the two different oven temperatures. The purpose of this study was to determine the effect of genetic background, oven temperature, and dry-roasting of less tender cuts upon tenderness, juiciness, flavor and acceptability and cooking losses of tender and less tender cuts of beef.

Body weight is fast becoming the major health problem in the United States. Recent estimates of the number of weight conscious people in the United States are now up to 75 million. One year ago, the estimate of overweight individuals was 60 million Americans who were overweight or should be concerned about watching their weight. There are also two million known diabetics who must control their disease and body weight by a restricted caloric intake.

Applesauce has long been considered an important food product in the United States. Approximately 25 percent of the fresh apples used by the industry in the U.S. are converted into sauce. Recent statistics indicated a further increase in consumption (Canning Trade Almanac, 1964). The reason why so large portion of the crop have been utilized for sauce manufacture is that we can use the desirable varieties for blending techniques in making sauce, and its fine particle character has some advantages as a kind of baby food. According to the U.S. standard grades of canned applesauce, Grade A (Fancy) applesauce should have a bright color, fine particle, uniform texture, and natural flavor of the fresh apple. However, how to manufacture a sauce to meet the Grade A requirement is a problem for food processors to face. Although many reports showed that the quality of applesauce was affected by the varietal characteristics, stage of maturation of the fresh apple, and post harvest storage (LaBelle et al, 1960; Smock and Neubert, 1950; Wiley and Toldby, 1960; Livingston et al, 1954), no information is available on systematic studies of the basic characteristics of the individual varieties grown in Utah. In recent years, freeze-dehydrated fruits and fruit products have been manufactured in an attempt to remove most of the water they contain while maintaining a minimum change in the quality of the resulting products. Freeze-dehydrated foods can be stored and transported without refrigeration, are light in weight, and have an extended shelf-life. These advantages, coupled with flavor retention capacity, have made freeze-dehydrated products important among processed products. Therefore, an attempt was made to evaluate the quality and nutritive value of freeze-dehydrated applesauce. The reconstituted freeze dehydrated applesauce was analyzed for chemical and organoleptic attributes and compared with canned applesauce. Studies were made on the effects of variety, maturity, and post-harvest storage on the quality of canned and freeze-dehydrated applesauce with regard to chemical constituents, physical properties, and flavor characteristics.

Studies were conducted using four phosphate compounds: sodium hexametaphosphate, sodium tripolyphosphate, sodium tetraphosphate, and tetrasodium pyrophosphate at 1, 5, and 10 per cent concentrations to ascertain their effects on fresh cherries, as well as their in vitro antimycotic effects against Botrytis sp., Penicillium expansum, and Rhizopus nigricans. A. summary of the findings are as follows: 1. Sodium tetraphosphate appeared to be the most effective antimycotic compound used in this investigation. A 10 per cent concentration of sodium tetraphosphate appeared to be the most effective antimycotic compound used in this investigation. A 10 per cent concentration of sodium tetraphosphate inhibited fungal growth on fresh cherries up to 30 days of storage at 34 degrees Farenheight and 94 per cent relative humidity, while the untreated controls showed fungal growth after 14 days at refrigeration storage. 2. Microscopic observations of treated lots of cherries revealed that the infecting fungi were predominantly Botrytis and Penicillium species. Penicillium was observed in all the control lots and caused the greatest amount of fungal infection. 3. In the in vivo and in vitro studies it was confirmed that an order of decreasing preservative effectiveness was sodium tetraphosphate, sodium hexametaphosphate, sodium tripolyphosphate, and tetrasodium pyrophosphate respectively.