The mango (Mangifera indica L.) is an appealing subtropical fresh fruit with a pleasant flavor and taste, high nutritional value, beneficial medicinal properties and various processing options. However, as is the case with most subtropical fruit, it is a sensitive commodity, prone to losses postharvestly. The South African mango industry is highly dependent on a hot water and cold prochloraz dip treatment, to control postharvest anthracnose and soft brown rot on fruit destined for export. However, negatve public perceptions of synthetic fungicides and its use on fresh produce for disease control has been increasing in major export markets such as the European Union. This growing concern from a public point of view is forcing industry to consider more environmentally acceptable methods to maintain quality of mangoes during extended export periods. ‘Tommy Atkins’ and ‘Kent’ mangoes either uninoculated or artificially inoculated with Colletotrichum gloesporioiedes, Botryosphaeria parva or sterile agar, were used to evaluate softer, greener alternatives, in this study. Fruit were subjected to either a hot, Bacillus amyloliquefaciens (PPCB004) containing dip treatment for two minutes or a 24 hour 1-methylcyclopropene (1-MCP) gas treatment at 16 ºC or no treatment. Fruit were then stored at 10 ºC under either 5% O2 and 5% CO2 (CA-1) or 3% O2 and 8% CO2 (CA-2) controlled atmospheres (CA) for 18 days and allowed to ripen for five days at 25 ºC. Similarly, uninoculated or artificially inoculated fruit subjected to B. amyloliquefaciens, 1-MCP or a combination of the two treatments was stored at 10 ºC for 18 days under conventional storage. ‘Tommy Atkins’ fruit were packed into bags made from four different film types, untreated or after being subjected to a cold B. amyloliquefaciens dip treatment and stored for 23 days at 10 ºC. Overall, ‘Kent’ fruit were more susceptible to anthracnose and SBR after artificial inoculation. In vivo inoculated ‘Tommy Atkins’ fruit, storage under CA-1 gave the best control of soft brown rot whilst CA-2 storage gave the best control of anthracnose. For quality retention no definite conclusion could be made for both cultivars after CA storage or the combination of 1-MCP pre-treatment and CA storage. The combination of 1-MCP pre-treatment and B. amyloliquefaciens maintained the quality of ‘Kent’ mangoes under conventional storage the best. Anthracnose severity on both cultivars was reduced with 1-MCP treated fruit combined with the biocontrol pre-treatment. Modified atmosphere packaging in this study was found to be ineffective in maintaining quality of mangoes. Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2011. / Microbiology and Plant Pathology / unrestricted
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:up/oai:repository.up.ac.za:2263/28723 |
| Date | 14 February 2012 |
| Creators | Van Deventer, Francois Johannes |
| Contributors | Korsten, Lise, vandeventer.f@gmail.com |
| Publisher | University of Pretoria |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Dissertation |
| Rights | © 2011, 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 |
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