The ripening of fruit, aside from its economic consequence, is of importance in the study of the development and physiology of plants. The fruit, being the reproductive organ of the plant, is fundamentally necessary for the continuation of the species. The production of fruit is also of major economic importance. The fruit is nurtured, not only by its own ability when young to produce carbohydrates by photosynthesis, but also by the translocation of sugar and other compounds produced int eh leaves. While young, the fruit appears to function as the modified leaf that it is believed to be. It is when the fruit matures that the changes known as ripening occur. In the ripening of the fleshy fruits, a change in color is usually observed. This change in color is through a loss of chlorophyll and an increase in the color pigments, anthocyanins, carotenes, and/or xanthophylls, etc. As the fruit ripens, an abscission layer is formed between the plant and the fruit; and the fruit eventually falls from the plant. Control of the length of time required for a fruit to develop and mature is attributed largely to genetic characters. The relation of the ripening fruit to a senescent leaf is apparent in that both lose their chlorophyll and in some cases become colored with other pigments. The eventual fall of leaves is also associated with the formation of an abcission layer between the leaf and the plant body. It seems logical, therefore, that the ripening of fruit could be considered as a senescence process. To the economic botanist, the control of senescence is of fundamental importance in the preservation of plant products. Control of the fruit could be useful in extending their period of utilization. In the studies reported here, attempts have been made to investigate the ripening process of the tomato fruit (Lycopersicum esculentum Mill. var. V. R. Moscow). These studies have been oriented toward the induction of ripening and some of the chemical changes that occur thereafter. Attempts have been made to find new agents for the induction of ripening and to examine established ripening inductants such as ethylene gas. This study also reports the effects of magnetic flux on the ripening of a fleshy fruit. This is a new and controversial concept in research on senescence. The effect of light and several light frequencies on the ripening of a tomato fruit has also been investigated. The changes in the concentrations of sugars, acids, and other compounds during the ripening period of tomato fruit ripened by artificial methods are compared with fruit naturally ripened on the plant.

Although much information is available in which the cholesterol level and concentration of other lipids in serum have been studied, only limited data have been reported for normal human adults and concentrations of fatty acids composition of lipid classes in serum. In recent study in this laboratory, five male adults who were in good health served as experimental subjects. They were on a self-chosen diet and received a test dose of Nicospan (buffered nicotinic acid) of 2 gm per day for three weeks of a six-week test period. About 30 ml of venous blood were obtained twice weekly from each subject after an overnight fast of at least 12 hours. Serum was separated from whole blood by standard procedures and the concentrations of total lipids, the distribution of lipid classes, and the fatty acid compositions of cholesterol esters, triglycerides, and phospholipids were determined and compared for three different periods of the study. The concentrations of total lipids for four subjects showed slight decrease during nicotinic acid therapy including 4 mg per 100 ml (7 per cent); 44 mg per 100 ml (7 per cent); 8 mg per 100 ml (1 per cent); 15 mg per 100 ml (2 per cent) for subjects GB, VT, MR, and RB respectively. Subject LN showed slightly higher values in the periods without nicotinic acid treatment. The results agree with previously reported data. Slight and rather inconsistent changes occurred in the lipid classes during the test period with nicotinic acid as compared to the pre- and post- test periods. The changes were not significant. The fatty acid compositions of serum cholesterol esters, triglycerides, and phospholipids of three subjects LN, VT, and RB were determined. Values on days with and without nicotinic acid therapy were studied and were compared with values determined on days during nicotinic acid therapy. In cholesterol esters, myristic, linoleic and arachidonic acids decreased during the period of nicotinic acid therapy whereas stearic and oleic acids slightly increased. In triglyceride, most of saturated fatty acids including myristic, palmitic and stearic acids and the polyunsaturated acid, linoleic, increased during nicotinic acid therapy whereas only oleic acid decreased during the treatment period. Fatty acids of phospholipids were reduced in palmitic, stearic and linoleic acids whereas values for oleic acid increased. The response of the subjects to the doseage of nicotinic acid was very little. If the size of the test dose and the study period were increased, as well as choosing subjects with higher initial serum total lipid and cholesterol values, greater response should be observed.

Importance of project Several months' curing time is needed to give cheddar cheese the desirable flavor demanded by the market. The exact length of time required for curing depends upon the flavor intensity desired, but the curing process is always costly and time-consuming. The practice of making cheddar cheese from pasteurized milk is now common throughout the industry. Many progressive cheese factories are pasteurizing their milk and enjoying the consequent benefits from a higher quality product. Although pasteurization has eliminated many of the quality problems in cheesemaking, it has resulted in even slower curing cheese. Much of the cheese research now being carried on is concerned with finding means to shorten the normal curing period without adversely affecting the quality of the product would be invaluable to the cheddar cheese industry. DK cheese starter The curing of cheddar cheese is made possible by the symbiotic growth of microorganisms in the cheese curd, the action of enzymes present in the milk, and the enzymes in rennet which are added to the milk. Many workers (2) (33) (39) have expressed the thought that the rate of ripening of cheese may be influenced by specific microorganisms. Dahlberg and Kosikowsky (14) have isolated a particular strain of Streptococcus faecalis which, when used in cheese starter, is reported to hasten the development of good cheddar flavor in cheese that naturally tends to cure rather than slowly. DK cheese starter is a culture of this reputedly successful strain of S. faecalis. Purpose of investigation Dahlberg and Kosikowsky (14) reported that fine highly flavored cheddar cheese was produced, and that a two-month reduction in curing time was obtained when DK cheese starter was combined with commercial lactic acid starter in cheese making. Vanderbeek (50) experimented with cheese starter containing a strain of S. faecalis which may or may not have been the same strain employed in DK starter. He found that S. faecalis starter did not reduce the normal curing period, and that a bitter flavor developed in all the cheese in which S. faecalis has been used. The purpose of this investigation is to use DK cheese starter in combination with commercial lactic acid starter to make cheddar cheese. The ultimate object of this work is to gather evidence for the cheese industry showing the advantages or disadvantages of the use of DK cheese starter in quality cheddar cheese production. Scope of problem DK cheese starter was used to make cheddar cheese in the exact manner prescribed by its advocates. Control cheese was made with commercial cheese starter and used as a basis for comparison. Any pronounced differences in the manufacture of the cheese as a result of the starter were recorded. Efforts were made to determine the effect of DK cheese starter on the rate of curing and the quality of the resulting cheese. All of the cheese was made int he College Creamery at Utah State Agricultural College during December 1949.

Each of thirteen lots of Cheddar cheese was made from 430 lb. of milk, and the protein recovered in the cheese and whey was compared with that in the original milk. Protein determinations on the milk, cheese and whey were made by an acid orange 12 dye binding test, and by Kjeldahl analysis. Similarly fat recovery was determined by using the Babcock fat test on milk, the modified Babcock test on cheese, and the Mojonnier test on whey. The total weight recovered as cheese and whey was 99 plus/minus .6% by Kjeldahl analysis and 97.7 plus/minus .6% by the dye binding test. Fat recovery was 97.0 plus/minus 1%. Even though Kjeldahl analysis gave better protein accountability than the dye binding method, because of its similarity the dye binding test along with fat testing could be used by cheese factories to account for two economically important milk constituents. Protein hydrolysis reduced the apparent percent protein in cheese and milk as measured by the dye binding test. However, Cheddar cheese containing 37-38% moisture and cured at 7.2 C was satisfactory for protein accounting up to 30 days of age.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Food Technology, 1955. / Includes bibliographical references (leaves 114-118). / by Stephen John Lirot. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nutrition and Food Technology, 1968. / Includes bibliographical references (leaves 151-154). / by Don Van Dyke. / M.S.

Thesis (Ph.D.) Massachusetts Institute of Technology. Dept. of Food Technology, 1957. / Vita. / Bibliography: leaves 263-270. / by Aaron Leo Brody. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Food Technology, 1960. / Includes bibliographical references (leaves 136-140). / by Thoams Laurence Fazzina. / Ph.D.

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Food Technology, 1967. / Vita. / Includes bibliographical references (leaves 163-169). / by Chokyun Rha. / Sc.D.

Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Food Technology, 1952. / MIT copy bound with: New packaging method for frozen swordfish steaks / Yaichi Aikawa. 1952. / Bibliography: leaf [41]. / by Edward Stuart Olney. / B.S.