Thesis (MScIng)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on June 18, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Chemistry, University of Alberta. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1960. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, 1920. / "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." "Reprinted from Iowa state college of agriculture and mechanic arts, Research bulletin, nos. 63 and 65, October, 1920, and November, 1920." Bibliography: p. 96b-96c, 128. Also available on the Internet.

[No abstract available] / Land and Food Systems, Faculty of / Graduate

[No abstract available] / Land and Food Systems, Faculty of / Graduate

[No abstract submitted] / Land and Food Systems, Faculty of / Graduate

No description available.

I declare that this is my own, unaided work. It is being submitted for the degree of Master of Science in the University of the Witwatersrand, Johannesburg. It has not been submitted before for any degree or examination in any other University. / Heat resistance and inactivation of processed meat spoilage lactic acid bacteria was investigated in vitro and by in-package pasteurization of South African vacuum-packaged vienna sausages. In vitro heat resistance of four lactic acid bacteria strains was low, since reductions of at least one log cycle in bacterial numbers occurred upon heating at 57, 60 and 63°C in quarter-strength Ringers solution for one minute. In vitro heat resistance data were used to calculate three in-package pasteurization treatments of increasing severity for vacuum-packaged vienna sausages. Depending on treatment, pasteurization in a water cooker at 67°C increased microbiological shelf life of sausages 10, 14 and 17 times that of control samples, during storage at 8'C. Although in-package pasteurization successfully decreased growth of spoilage lactic acid bacteria and increased product shelf life fit did not entirely prevent spoilage by pediococci. Since pasteurization also promoted growth of potentially pathogenic Bacillus and Clostridium, safety of pasteurized vacuum-packaged vienna sausages was compromised. / Andrew Chakane 2018

<i>Lactobacillus plantarum</i> (<i>Lb. plantarum</i>) NRRL B4496 and <i>Lactococcus lactis</i> (<i>Lc. lactis</i>) NRRL B1821 prolidase genes were isolated, cloned, and sequenced. The sequence-confirmed genes were subcloned into the expression systems. The recombinant prolidases from the pKK223-3 systems were purified through ammonium sulphate precipitation and anion-exchange column chromatography. Recombinant <i>Lb. plantarum prolidase</i>, however, demonstrated a loss of activity during the purification. The following characterization work was performed on purified recombinant <i>Lc. lactis prolidase</i>. <p>The mass spectroscopic result and the molecular modelling suggested a 80 kDa homodimer with two metal cations at the catalytic centre of the prolidase. The optimum temperature was 50 ºC and showed more than 50% activities between 40 and 55 ºC. The enzyme was most stable at 30 ºC and withstood 20 min of heat-treatment up to 60 ºC, however, lost activity over 70 ºC. Circular dichroism indicated a denaturation temperature of 67 ºC. The optimum pH was 6.5 for hydrolyzing Leu-Pro and the enzyme did not display any activity below pH 5.5 nor above pH 7 with this peptide. However, Phe-Pro was hydrolyzed the fastest at pH 7 and Arg-Pro had a maximum rate at pH 9. This metallopeptidase exhibited a broad range of metal cation preference, hydrolyzing Leu-Pro with Mn++, Co++, Zn++, Ca++, and Mg++. Further kinetic analysis showed unusual allostery of the enzyme (Hill coefficient: 1.3). The unique substrate intakes onGlu-Pro and tripeptides were observed while Val-Pro was not hydrolyzed. The molecular modelling of this prolidase suggested a difference in the substrate specificity resulting from a loop structure, L33 to R40, near the substrate binding site.