Thesis (Ph. D.)--Columbia University, 1941. / Reproduced from type-written copy. Vita. Includes bibliographical references (p. 57-59).

Thesis (Ph. D.)--Columbia University. / Vita. Includes bibliographies.

Thesis (doctoral)--Lund University, 1994. / Added t.p. with thesis statement inserted.

Thesis (Ph. D.)--Columbia University, 1927. / Vita. Bibliography: p. [42-43].

Thesis (Ph. D.)--Columbia University, 1923. / Vita. "Reprinted from the Journal of the American chemical society, vol. 44."

Thèse. Sc. nat. Paris. 1945. No 2972. / Includes bibliographical references (p. [177]-184).

Thesis (PH. D.)--Columbia University, 1946. / Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 37-39.

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes footnotes.

Doctor of Philosophy / Department of Grain Science and Industry / Yong Cheng Shi / The reaction of starch and octenylsuccinic anhydride (OSA) produces lipophilic starch that has the ability to stabilize oil-in-water emulsions. The functional properties of octenylsuccinate (OS) starch depend on its molecular structure and distribution of OS groups. Structures of OSA and OS starches were investigated by NMR spectroscopy. In granular OS starches, OS groups were substituted at O-2, O-3 positions, but not the O-6 position. Distribution of OS groups was investigated by enzyme hydrolysis followed by chromatography analysis. OS substitution predominantly occurred at the amorphous region of the starch granules. OS starch of degree of substitution (DS) 0.018 had OS groups located close to the branching points, whereas the OS substitution in OS starch of DS 0.092 occurred near non-reducing ends as well as the branching points. OS starches with different substitution patterns were prepared from two approaches. OS starches from the first approach had OS substitution near the branching points or non-reducing ends, whereas OS starches from the second approach had OS groups distributed randomly throughout the starch chains. A method of preparing OS starch by dry heating a mixture of waxy maize starch and OSA was developed. The optimum reaction was investigated and found to be pH 8.5 by addition of 3% NH4HCO3, 180 °C and 2 h. Reaction efficiency of ca. 90% was obtained at OSA levels from 1 to 6%. The OS starch had a DS of 0.0202 with 98% solubility when reacted with 3% OSA. Transglucosidation occurred during the reaction. The OS starch had a degree of branching of 19.8 %. The highly debranched OS starch showed excellent emulsification property for vitamin E and vitamin A. The structural changes of insoluble native waxy maize starch granules to cold watersoluble pyrodextrin during dextrinization under acidic conditions were investigated. We proposed that the starch was hydrolyzed by acid in the amorphous regions. Unwinding of the double helices also occurred, and crystallite size decreased. Starch molecules were hydrolyzed into small molecule fractions but remain in a radial arrangement. Glycosyl linkages including - (1 2), -(1 6), -(1 2), and -(1 6) linkages were formed and the majority starch chain terminals were 1,6-anhydro- -D-glucopyranose. Transglucosidation occurred during dextrinization and the resulted pyrodextrin was highly branched.

This research project is concerned with the use of an amylolytic yeast, Endomycopsis sp., for simultaneous production of yeast protein and crude amylase preparations from natural starch materials. The Endomycopsis yeasts were cultivated alone and in combination with other yeasts which are unable to attack starch directly. The propagations were carried out in the presence of urea and phosphate, under aerobic conditions, with vigorous agitation, at pH 5.0 and 28°C. At daily intervals, the cultures were analyzed for protein yield, cell density, and amylase activity. The cell crop harvested after propagation of Endomycops is yeasts on 6.0% potato media contained 19% protein and the culture filtrate obtained after biomass separation had an activity of 1.5 units. Variations in activity and protein content were observed, depending on the starch substrate used, the concentration of urea added, and apparently, the amount of oxygen supplied. Mixed preparations using Candida utilis as ancillary yeast, gave higher protein yields and amylase activities compared to single propagations of Endomycopsis sp. and mixed propagations with Saccharomyces cerevisiae. Purple yam and cassava tubers were examined for protein enrichment and amylase production. It was observed that the protein content of the cell crops obtained from these substrates could be increased about ten-fold but that the amylase activities of the culture filtrates were very low . / Land and Food Systems, Faculty of / Graduate