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Antimicrobial properties of phenolic compounds from sorghum
Dissertation (MSc (Food Science and Technology))--University of Pretoria, 2007.
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| Format: | Thesis |
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University of Pretoria
2013
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| _version_ | 1867613552957718528 |
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| access_status_str | Open Access |
| author2 | Buys, E.M. (Elna Maria) |
| author_browse | Buys, E.M. (Elna Maria) |
| author_facet | Buys, E.M. (Elna Maria) |
| collection | Thesis |
| dc_rights_str_mv | © 2006, 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 | Dissertation (MSc (Food Science and Technology))--University of Pretoria, 2007. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/22931 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:37:58.345Z |
| 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:2263/22931 Antimicrobial properties of phenolic compounds from sorghum Buys, E.M. (Elna Maria) Duodu, Kwaku Gyebi khadambiN@arc.agric.za Khadambi, Tshiwela Norah Antimicrobial Properties Phenolic Compounds Sorghum UCTD Dissertation (MSc (Food Science and Technology))--University of Pretoria, 2007. Sorghum grains contain phenolic compounds that have been shown to have many favourable effects. In this study the levels of phenolic compounds in condensed tannin and condensed tannin-free sorghums have been determined and the antimicrobial activity of phenolic extracts from bran fractions of the respective sorghums has been further evaluated against pathogenic bacteria Bacillus cereus ATCC 1178, Escherichia coli ATCC 25922 and Listeria monocytogenes ATCC 7644. Defatted bran fractions prepared from a condensed tannin sorghum variety (red) and a condensed tannin-free sorghum variety (white) were analysed for their content of total phenols and condensed tannins. Total phenols were determined using the Folin-Ciocalteu method and condensed tannins with the vanillin-HCL method. Total phenols and condensed tannins of the bran fractions were extracted with aqueous acetone (75 % v/v) and acidified methanol (1% HCL v/v in methanol) respectively, using a bran-to-solvent ratio of 1:4 (w/v). Red sorghum bran contained a higher amount of total phenols and condensed tannins (33.18 mg tannic acid equivalent/g and 117.98 mg catechin equivalent/g of the bran fractions, respectively) than white sorghum bran (6.81 mg tannic acid equivalent/g and 8.52 mg catechin equivalent/g of the bran fractions, respectively). Freeze-dried sorghum crude phenolic extracts (CPE) obtained from defatted bran fractions of condensed tannin and condensed tannin-free sorghum varieties were evaluated for their antimicrobial activities against Bacillus cereus ATCC 1178, Escherichia coli ATCC 25922 and Listeria monocytogenes ATCC 7644 pathogenic bacteria. The extracts were tested at 1, 2, 4 and 20 % concentrations (w/v) in methanol using the paper disc diffusion method and absolute methanol was used as a control. The condensed tannin-free sorghum CPE at concentrations 1, 2 and 4 % had no inhibitory effects on the bacteria tested but was effective against Gram-positive bacteria, B. cereus ATCC 1178 and L. monocytogenes ATCC 7644 at a concentration of 20 %. The condensed tannin sorghum CPE was effective against B. cereus ATCC 1178 and L. monocytogenes ATCC 7644 at concentrations 1 , 2 , 4 and 20 %. None of the tested sorghum extracts inhibited the Gram-negative bacteria, E. coli ATCC 25922. Phenolic extracts from condensed tannin sorghum may be used as antimicrobial agents to prevent the growth of Gram-positive bacteria, B. cereus ATCC 1178 and L. monocytogenes ATCC 7644. Food Science unrestricted 2013-09-06T14:02:16Z 2007-03-02 2013-09-06T14:02:16Z 2006-04-24 2007-03-02 2007-03-02 Dissertation Khadambi, T 2006, Antimicrobial properties of phenolic compounds from sorghum, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/22931 > http://hdl.handle.net/2263/22931 http://upetd.up.ac.za/thesis/available/etd-03022007-164705/ © 2006, 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 application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf University of Pretoria |
| spellingShingle | Antimicrobial Properties Phenolic Compounds Sorghum UCTD Antimicrobial properties of phenolic compounds from sorghum |
| title | Antimicrobial properties of phenolic compounds from sorghum |
| title_full | Antimicrobial properties of phenolic compounds from sorghum |
| title_fullStr | Antimicrobial properties of phenolic compounds from sorghum |
| title_full_unstemmed | Antimicrobial properties of phenolic compounds from sorghum |
| title_short | Antimicrobial properties of phenolic compounds from sorghum |
| title_sort | antimicrobial properties of phenolic compounds from sorghum |
| topic | Antimicrobial Properties Phenolic Compounds Sorghum UCTD |
| url | http://hdl.handle.net/2263/22931 http://upetd.up.ac.za/thesis/available/etd-03022007-164705/ |