Thesis (M. Sc.)(Microbiology)--University of Pretoria, 2005. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web..

Thesis (Ph. D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 89-102). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 89-102). Also available on the Internet.

Traditional fermented food, especially fermented maize and sorghum represents an important part of the diet of peri-urban and rural communities in South Africa. In this study a survey was conducted to determine the popularity and utilization of “Ting” in the Limpopo Province of South Africa. The following areas were selected for the study: Venda, Giyani, Bolobedu and Polokwane. Ting samples were collected from different areas and from different local families. Gram positive, catalase-negative, oxidase negative, non-motile cells were presumptively identified as lactobacilli. Isolates were assigned to a genus on the basis of key characteristics. Growth at 10, 15 and 45oC in MRS broth wase evaluated visually after 72h of incubation. Tests for the catalase reaction, production of gas from glucose and growth at 7 and 10% NaCl concentrations were performed. API 50CHL medium and API 50CH strips were used to identify all the isolates to species level. Microorganisms from “Ting” fermented from both sorghum and maize were bacteria, which belong to the genus Lactobacillus, Leuconostoc and Pediococcus. Lactobacillus pentosaceus, and Lactobacillus plantarum, Lactobacillus pentosaceus were dominant in the fermentation of maize, while Lactobacillus cellobisus, Leuconostoc mesenteroides, Lactobacillus collinoides, Lactobacillus brevis, Lactobacillus fermentum and Lactobacillus curvatus were identified as bacteria from fermented “Ting” sorghum. The use of polyacrylamide gel electrophoresis (PAGE) of total soluble proteins, together with computer analysis was used to analyse the resultant protein profiles. L. plantarum, L. pentosus and P. pediococcus were the most dominant isolates. / Dissertation (MSc (Microbiology))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted

This research investigated the effects of Pediococcus spp. on Oregon Pinot noir wines. Pediococcus (P. parvulus (7), P. damnosus (1), P. inopinatus (1)) isolated from Oregon and Washington state wines demonstrated differences in their susceptibility to SO��� with some isolates growing well in model media at 0.4 mg/L molecular SO���. All isolates were all able to degrade p-coumaric acid to 4-vinyl phenol. The conversion of p-coumaric acid to 4-VP by pediococci resulted in accelerated production of 4-EP by B. bruxellensis in a model system. Growth of the pediococci isolates in Pinot noir wine resulted in a number of chemical and sensory changes occurring compared to the control. Very low concentrations of biogenic amines were measured in the wines with only wine inoculated with P. inopinatus OW-8 having greater than 5 mg/L. D-lactic acid production varied between isolates with OW-7 producing the highest concentration (264 mg/L). Diacetyl content of the wines also varied greatly. Some wines contained very low levels of diacetyl (< 0.5 mg/L) while others contained very high concentrations (> 15 mg/L) that were well above sensory threshold. Despite suggestions to the contrary in the literature, glycerol was not degraded by any of the isolates in this study. Color and polymeric pigment content of the wines also varied with wine inoculated with OW-7 containing 30% less polymeric pigment than the control. This may be related to acetaldehyde as a number of Pediococcus isolates, including OW-7, reduced the acetaldehyde content of the wine. Sensory analysis revealed differences in the aroma and mouthfeel of the wines compared to each other and to the control. In particular growth of some isolates produced wines with higher intensities of butter, plastic, and vegetal aromas while other also had lower perceived astringency. / Graduation date: 2013