Thesis (M.S.)--University of Wisconsin--Madison, 1941. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 32-33).

Thesis (M.S.)--University of Wisconsin--Madison, 1940. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 41-47).

Thiamine is an important nutrient found in significant amounts in wheat flours. This vitamin is heat labile thus destruction occurs during bread baking. Using a kinetic approach, the effect of heat and pH on thiamine degradation in a model system were studied. In order to compare the stability of thiamine from natural (whole wheat) and synthetic (enriched white) sources, thermal destruction of thiamine in the two breads was investigated. Destruction rates of thiamine hydrochloride in phosphate buffer at pH 6.0 and temperatures between 80 and 120°C were measured. The breakdown reaction could be described by first order kinetics. An energy of activation of 34.2. kcal/mole was obtained. Destruction rates of thiamine hydrochloride in phosphate buffer at 120°C were measured for pH values between 4.0 and 7.0. The reaction rate increased as the system was made more alkaline, with greater destruction at pH 6.0 and above. Thiamine losses in an enriched white flour system baked at a nominal temperature of 246°C (475°F) for 60, 75 and 90 min were found to be 2.4, 27.9 and 29.2%, respectively. Two experiments were carried out with 450 g (1 lb) enriched white loaves baked at 221°C (430°F). Baking times were 30 min for the first experiment, and 15, 37 and 60 min for the second experiment. No appreciable thiamine destruction were found in either experiment. The main investigation was with a semi-model system of 12g bread loaves made from enriched white and whole wheat flours. Four different nominal oven temperatures of 177, 221, 246 and 288°C (350, 425, 475 and 550°F) were used with four different baking times for each run. The pH of the dough and baked bread were determined. Oven, crust and loaf center temperatures were monitored. The mass average temperature data of the bread during baking showed a changing rate of temperature rise, and because of this, it was not possible to obtain kinetic data. However, a linear relationship was obtained when the logarithm of the percent thiamine retention was plotted against time. This experiment showed a lower thiamine stability with higher oven temperature. Thiamine was less stable in whole wheat bread than in enriched white bread. This might be explained by higher pH and ash content in whole wheat bread. Thiamine losses during normal baking of whole wheat and enriched white bread were found to be in the range of 28.3 to 47.8%. / Land and Food Systems, Faculty of / Graduate

The lactic dehydrogenase activity in plasma and tissues was measured in the thiamine-deprived, the oxythiamine-treated and the pyrithiamine-treated rats as well as the control rats. The lactic dehydrogenase levels of brain and kidney were significantly increased by oxythiamine treatment. The enzyme activity in heart was markedly decreased only in the thiamine-deprived rats. Unlike the above tissues, the enzyme levels in liver were decreased by 29-44 per cent in all three types of thiamine deficiency, However, the enzyme activity in plasma was significantly increased only by pyrithiamine administration. The distribution patterns of lactic dehydrogenase isozymes were electrophoretically examined in these deficiencies. No significant difference among the three thiamine-deficient groups was observed in brain, kidney, and heart. All five isozymes were observed in proportions that are highly specific for the tissues involved. Two extra bands, in addition to five major bands, were found in liver. In thiamine deprivation liver LDH_3 was noticeably more abundant than LDH_2 in some cases, which is opposite to that found in the control. One extra band between LDH_2 and LDH_3 was absent in liver after pyrithiamine treatment. No noticeable difference in the isozyme distribution of plasma was found among the three thiamine-deficient groups. Blood pyruvate along with lactate was significantly increased by oxythiamine treatment. Pyrithiamine administration also caused a marked increase of blood pyruvate along with lactate only in the phase of the polyneuritic convulsion. Remarkable increases in weight of the adrenal glands were observed in all three cases.

Call number: LD2668 .T4 1944 H62 / Master of Science

The blood thiamine concentration of 11 subjects was determined by means of the Friedemann and Kmieciak (1943) method every 5 days during a 30-day experimental period. Study I was conducted on 5 students in 1947 and Study II was conducted on 6 students in 1948. The subjects in both studies were on diets in which their intake of ascorbic acid only was controlled. A record was kept of each subjects food intake. The daily values for total Calories, non-fat Calories and thiamine in the diet were obtained from food tables. Non-fat Calories, the ratio of non-tat Calories to total Calories, thiamine to 1000 Calories and thiamine to non-fat Calories were calculated. The blood thiamine values for the subjects in Study I (all girls) ranged from 4.91 to 10.85 mcg per cent. There was a general decrease throughout the study in the mean intake of thiamine expressed in terms of mcg per 1000 Calories and mcg per 1000 non-fat Calories. The greater the decrease in thiamine intake in terms of mcg per 1000 non-fat Calories the greater was the loss of blood thiamine. The values for thiamine in the blood of the boys in Study II ranged from 8.00 to 15.32 mcg per cent and for the one girl in Study II from 8.35 to 13.93 mcg per cent. The blood thiamine values for the subjects in Study II did not indicate the same relationship to thiamine intake as did those in Study I. There was an increase in the concentration of the thiamine in the blood even though there was a decrease in the mean thiamine intake from the beginning to the end of the experiment. It would appear, therefore, that the boys obtained sufficient thiamine throughout the 30-day period. No data have been obtained which indicate whether or not there are variations from day to day in the concentration of thiamine in the blood when subjects are maintained on a constant intake of thiamine. A metabolism study using 5 adult women as subjects was planned in order to determine the daily values for thiamine in the blood when subjects were maintained on a controlled diet for a period of 52 days. An unpublished micro-method for the determination of thiamine in the blood developed by Dr. H. Burch (1948) was to be used. The experimental diet consisted of a basal diet providing approximately 1000 Calories and 300 mcg of thiamine with additions to the basal diet planned in units providing approximately 500 Calories and 150 mcg of thiamine. The values for protein, fat, carbohydrate and total Calories were obtained, from food tables. Non-fat Calories were calculated and the thiamine content of the food was determined by analysis. All 5 subjects ate the same food each day. In spite of the fact that considerable preliminary work was performed before the study started the blood thiamine values obtained in the nutrition laboratory were always significantly lower than results obtained by other workers. It was decided to freeze the blood samples after the protein had been removed and work on certain aspects of the method before any analyses of the blood thiamine were made. Further study of the Burch method included variation in the amounts of potassium acetate used, use of different trichloroacetic acid reagents, tests for enzyme activity, variations in the incubation procedure, variations in the procedure for the oxidation to thiochrome and in the extraction of thiochrome, reading samples sooner after transfer to optically matched tubes, variations in the irradiation procedure, use of all new reagents, use of another micro-photofluorometer, development of standard curves and the determination of the response of two subjects to an oral test dose of thiamine hydrochloride. None of these variations resulted in a solution of the problem. Suggestions for future work with the Burch method are discussed. / Graduation date: 1950

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No description available.

Graduation date: 1945