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Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum
Thesis (PhD)--University of Pretoria, 2011.
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University of Pretoria
2013
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| _version_ | 1867613538074230784 |
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| access_status_str | Open Access |
| author2 | Cloete, T.E. (Thomas Eugene), 1958- |
| author_browse | Cloete, T.E. (Thomas Eugene), 1958- |
| author_facet | Cloete, T.E. (Thomas Eugene), 1958- |
| collection | Thesis |
| dc_rights_str_mv | © 2009 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD)--University of Pretoria, 2011. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/28898 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:37:44.183Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/28898 Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum Cloete, T.E. (Thomas Eugene), 1958- Theron, Jacques Steenkamp, Emma Theodora evelyn.madoroba@gmail.com Madoroba, Evelyn Lactic acid bacteria Fermentation of sorghum Southern africans Ting UCTD Thesis (PhD)--University of Pretoria, 2011. Ting is a cooked fermented sorghum food that is popular amongst southern Africans for its sour taste and unique flavour. However, major challenges are associated with large-scale production and marketing of this spontaneously fermented food due to inconsistent microbiological and sensory quality. The use of starter cultures may circumvent these limitations. Prior to engaging starter cultures, detailed knowledge of the microbial diversity and dynamics during fermentation is important. Therefore, the aim of this study was to investigate microbial diversity and dynamics during sorghum fermentations, and to clarify the role of starter cultures regarding the microbiological safety and consumer acceptance of sensory characteristics of fermented ting. A culture-independent approach, based on the use of PCR-denaturing gradient gel electrophoresis (DGGE), revealed that Lactococcus lactis, Lactobacillus curvatus, Weissella cibaria and some Enterobacteriaceae were predominant at the end of spontaneous sorghum fermentations. Culture-dependent methods indicated that Lb. fermentum, Lb. plantarum, Lb. rhamnosus, E. faecalis, E. mundtii, W. cibaria and L. lactis were predominant at the end of fermentation. These results not only indicated the predominant bacteria during sorghum fermentation, but also indicated that a combined approach is required to reveal microbial diversity and dynamics during spontaneous sorghum fermentations. Based on the above results, L. lactis, Lb. fermentum, Lb. plantarum and Lb. rhamnosus were evaluated as starter cultures for production of ting. All the starter cultures were able to ferment sorghum, but the lowest pH and highest lactic acid was produced in naturally fermented sorghum inoculated with L. lactis. This fermentation showed an increase in the number of lactic acid bacteria and yeasts, whilst pathogen counts decreased. Ting from this fermented gruel, in contrast to naturally fermented sorghum, had sensory properties preferred by panelists. The results indicated that the use of L. lactis in starter cultures may result in ting with consistent and acceptable attributes. Microbiology and Plant Pathology unrestricted 2013-09-07T14:26:33Z 2009-11-02 2013-09-07T14:26:33Z 2009-09-02 2011-11-02 2009-10-21 Thesis Madoroba, E 2009, Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/28898 > D694/ag http://hdl.handle.net/2263/28898 http://upetd.up.ac.za/thesis/available/etd-10212009-174731/ © 2009 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Lactic acid bacteria Fermentation of sorghum Southern africans Ting UCTD Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum |
| title | Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum |
| title_full | Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum |
| title_fullStr | Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum |
| title_full_unstemmed | Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum |
| title_short | Molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum |
| title_sort | molecular characterization and population dynamics of lactic acid bacteria during the fermentation of sorghum |
| topic | Lactic acid bacteria Fermentation of sorghum Southern africans Ting UCTD |
| url | http://hdl.handle.net/2263/28898 http://upetd.up.ac.za/thesis/available/etd-10212009-174731/ |