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Antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge
Dissertation (MSc (Food Science))--University of Pretoria, 2015.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613606146736128 |
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| access_status_str | Open Access |
| author2 | Gaspar, A.R.M. (Anabella Regina Marques) |
| author_browse | Gaspar, A.R.M. (Anabella Regina Marques) |
| author_facet | Gaspar, A.R.M. (Anabella Regina Marques) |
| collection | Thesis |
| description | Dissertation (MSc (Food Science))--University of Pretoria, 2015. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/109999 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:49.043Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/109999 Antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge Gaspar, A.R.M. (Anabella Regina Marques) roslynn.allan@gmail.com Buys, E.M. (Elna Maria) Allan, Roslynn Sorghum Peptide Phenolic compound Antioxidant Dissertation (MSc (Food Science))--University of Pretoria, 2015. Non-communicable diseases (e.g. cancer and cardiovascular disease [CVD]) and diarrhoea affect many people around the world; often leading to death. Free radicals may play a role in the development of cancer while angiotensin converting enzyme (ACE) has been found to cause an increase in blood pressure which may lead to CVD. Sorghum, often consumed as a fermented porridge, is a good source of phenolic compounds and bioactive peptides which exert effects such as scavenging free radicals, inhibiting ACE and hindering the growth of pathogenic Escherichia coli (E. coli) which causes diarrhoea. Therefore, fermented sorghum porridge may have potential as a functional food with health-promoting properties. This study investigated the effect of sorghum type (white or red), lactic acid fermentation and simulated in vitro gastro intestinal digestion on in vitro radical scavenging activity, ACE inhibition and antimicrobial activity of sorghum porridge in relation to content of phenolic compounds and peptides. Sorghum type and fermentation had no effect on total phenolic content (Folin-Ciocalteu assay) but in vitro digestion led to a significant increase. Phenolic acids (ferulic, caffeic, pcoumaric and p-hydroxybenzoic acid) and flavonoids (catechin, naringenin and luteolin) were found in the supernatants from sorghum porridge. Sorghum type, fermentation and digestion led to varied effects on the individual phenolic compounds. Protein and peptide contents were significantly higher in supernatants from red, fermented and digested sorghum porridges compared to their white, unfermented and undigested counterparts respectively. Sorghum type and fermentation had no significant effect on ABTS radical scavenging Department of Food Science University of Pretoria iii activity or ACE inhibitory activity but supernatants from digested sorghum porridges had significantly higher ABTS radical scavenging activity (33.61- 56.03 µM TE/ g porridge) and ACE inhibitory activity (95.68 – 124.85 ACE inhibitory units/ g porridge) than their undigested counterparts (7.77- 29.04 µM TE/ g porridge for ABTS radical scavenging activity) and (7.55 – 54.02 ACE inhibitory units/ g porridge for ACE inhibitory activity). High correlation (coefficient of determination R2 = 0.87) between total phenolic content and ABTS radical scavenging activity suggested that phenolic compounds mainly caused the radical scavenging. Low correlation (coefficient of determination R 2 = 0.42) between protein content and ACE inhibitory activity indicated that large molecular weight protein species may not inhibit ACE and that other non-proteinaceous components, such as phenolic compounds, may inhibit ACE. All samples partially inhibited two pathogenic strains of E. coli but sorghum type, fermentation and digestion did not show distinctive effects on the bacteriostatic effects against E. coli for red sorghum porridge. On the other hand, for white sorghum porridge, fermentation or digestion led to a significant increase in the zone of inhibition of E. coli. The radical scavenging, ACE inhibition and bacteriostatic properties of the supernatants from sorghum porridge indicate that it may contribute to reduction of conditions associated with cancer, CVD and diarrhoea. Since sorghum type and fermentation had no significant effect on radical scavenging, ACE inhibition and antimicrobial activity, the consumption of white or red, unfermented or fermented sorghum porridge may have positive health-promoting properties to the consumer. Furthermore, this work demonstrates the potential for sorghum porridge to be used as a functional food. Food Science MSc (Food Science) 2026-05-15T17:26:01Z 2026-05-15T17:26:01Z 16/02/12 2015 Dissertation http://hdl.handle.net/2263/109999 en application/pdf |
| spellingShingle | Sorghum Peptide Phenolic compound Antioxidant Antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge |
| title | Antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge |
| title_full | Antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge |
| title_fullStr | Antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge |
| title_full_unstemmed | Antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge |
| title_short | Antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge |
| title_sort | antioxidant and angiotensin converting enzyme inhibitory activities of fermented sorghum porridge |
| topic | Sorghum Peptide Phenolic compound Antioxidant |
| url | http://hdl.handle.net/2263/109999 |