Thesis (Ph.D.) - University of St Andrews, April 2008. / Restricted until 11th April 2010.

Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Abstracted in Dissertation abstracts, v. 23 (1963) no. 9, p. 3111-2. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 32-34.

Thesis (MSc)--University of Stellenbosch, 2007. / Bibliography.

Thesis (Ph. D.)--University of Delaware, 2007. / Principal faculty advisor: Colin Thorpe, Dept. of Chemistry & Biochemistry. Includes bibliographical references.

Six auxotrophic mutants of A. nidulans were crossed in a dialell cross system to obtain heterokaryous and heterozygous diploids. In order to ascertain their lipid accumulation ability, some of these mutants and diploids were tested in a minimal medium (with 3% glucose + 0.6% NaNO3), either in a shaker or in an incubator without agitation. Both, the mutants and diploids, exhibited only 4.6% lipid, on a dry weight basis. With the aim of optimising culture conditions for lipid accumulation, a wild type was cultivated in a range of different media and cultural conditions. The best yield (about 24%), was achieved in a modified minimal medium (MM + 12% glucose + 0.1% NaNO3), with a vortex stirrer device. The lipid composition of wild type 16 grown in a fermenter was determined. The results obtained from cells grown in two different media and using two extraction methods were compared. Fractionation of the total lipid on a Florisil column showed that this strain is composed of 86% neutral lipid, 7% glycolipid and 7% phospholipid, after isopropanol (IP) extraction, whilst chloroform-methanol (CM) extraction gave 75% neutral lipid, 8% glycolipid and 17% phospholipid. A further fractionation on hydrated Florisil showed that CM extracted sterols (both free and esterified) more efficiently than IP. Therefore, CM was considered a better extraction method, particularly for protein-bound lipids. The separation of the neutral lipid fraction into sub-classes also showed that the enhanced lipid content achieved in modified minimal medium, compared with a previously reported medium, was accounted for mainly by an increase, not in the triglycerides as was expected, but in the amount of sterols. TLC analysis of glycolipid and phospholipid from IP and CM extraction demonstrated two major glycolipid components (monoglycosyl and diglycosyl diglycerides) and that phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were the principal phospholipids with lesser amounts of phosphatidylinositol, phosphatidylserine, phosphatidylglycerol, cardiolipin and phospbatidic acid (PA) after CM extraction, whilst after IP extraction only PC, PE and PA were found. Another significant difference between the two extraction methods is the large amount of PA found after CM extraction, but not after IP, showing that, almost certainly, phospholipase D activity had occurred during the process of extraction and/or storage of the lipid. It was also found that the principal phospholipid attacked by the enzyme was PC. The fatty acid composition was determined by GLC. The major fatty acids found in the total lipid were: 16:0 =21%; 17:0 =5%; 18:0 =18%; 18:1 = 20%; 18:2 = 35%. Each lipid class showed a different and distinctive fatty acid composition, exhibiting variation with the growth medium and extraction method used. Of particular interest was the sterol ester fraction which contained margarinic acid (17:0) as its only fatty acid.

The objective of this study was to determine the effect of different fat inclusion levels and fat types on the physical and chemical attributes, lipid oxidation, fatty acid composition and sensory characteristics of warthog cabanossi. To achieve this, three types of cabanossi with different pork backfat levels (10 percent, 20 percent and 30 percent) were produced for the first experiment. The results from the study showed that different inclusion levels of pork backfat had an influence (P ≤ 0.05) on the physicochemical and fatty acid composition of warthog cabanossi but did not influence lipid oxidation (P > 0.05). The highest (P ≤0.05) pH, weight and moisture decline was observed in the 10 percent pork backfat cabanossi compared to the 20 percent and 30 percent treatments. However, no differences (P > 0.05) in the water activity of the product were observed. As expected total fat was lower in the 10 percent fat treatment and increased concomitantly. Similarly, protein, ash and salt were higher in the 10 percent fat cabanossi and decreased concomitantly. Differences in the fatty acid composition were observed between treatments. Furthermore, backfat level affected the sensory attributes and consumer acceptance of the cabanossi. Ten percent backfat cabanossi was scored higher (P ≤0.05) for most sensory attributes. Consequently, it was observed that the consumer panel preferred and scored the 10 percent fat cabanossi higher with regards to appearance and taste. In the second experiment, two cabanossi treatments of different fat types (pork backfat and fat-tailed sheep backfat) were produced. The weight loss, moisture content, pH, water activity and salt content did not differ (P > 0.05) between the two cabanossi products. However, there were differences (P ≤0.05) in the protein, fat and ash contents; where protein and ash were higher in the pork backfat cabanossi whilst fat was higher in the sheep backfat cabanossi. Thiobarbituric reactive substances (TBARS) were similar (P > 0.05) between the two fat types cabanossi which could be explained by similar fatty acid profiles being reported for the two cabanossi although the n-6:n-3 ratio was higher (P ≤0.05) in sheep backfat cabanossi. Results from the descriptive sensory analysis showed two distinct products (P ≤0.01) where pork backfat cabanossi scored higher for most attributes. However, the lower scores for sheep backfat cabanossi were within an acceptable range. Sheep backfat cabanossi were also scored for unique attributes that were not detected in the pork backfat cabanossi. This study concluded that fat-tailed sheep backfat can be used to produce an unique cabanossi product of acceptable quality.