M.Sc. / Bananas are climacteric fruit which are characterised by a low rate of ethylene production and respiration during the pre-climacteric phase, followed by a sudden burst in ethylene production and respiration during ripening. Ethylene is a gaseous plant hormone that accelerates the ripening of climacteric fruit. In order to extend the shelf life of bananas the action or synthesis of ethylene must be inhibited or delayed. Examples of such inhibitors are 1- methylcyclopropene (1-MCP) an inhibitor of ethylene action, and aminoethoxyvinylglycine (AVG), an inhibitor of ethylene synthesis. The purpose of this research was to compare the effect of these two inhibitors on ripening of bananas. 1-MCP acts by blocking the ethylene receptors permanently. The results of this study indicated that 500 nL.L-1 1-MCP is more effective in delaying ripening of banana than AVG, although AVG delivered a better quality fruit in terms of colour. To be effective, bananas must be pre-treated with 1-MCP before they exposed to ethylene. The results also indicated that, the effectiveness 1-MCP to delay ripening decreases with storage time. The results show that ethylene binding to its membrane bound receptors is reversible if the exposure time to ethylene is less than 8 hours. Exposure to ethylene for 8 hours or more results in irreversible binding. However, binding only becomes permanent when exposure to ethylene exceeds 16 hours. For this reason treatment with 1-MCP becomes ineffective after exposure to ethylene for 24 hours due to the fact that ethylene has bound irreversibly and permanently to its binding sites and cannot be displaced by 1-MCP.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:6832 |
| Date | 26 May 2010 |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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