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Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent
Dissertation (MEng)--University of Pretoria, 2016.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2016
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| _version_ | 1867613679084634112 |
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| access_status_str | Open Access |
| author2 | Focke, Walter Wilhelm |
| author_browse | Focke, Walter Wilhelm |
| author_facet | Focke, Walter Wilhelm |
| collection | Thesis |
| dc_rights_str_mv | © 2016 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 (MEng)--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/57478 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:58.654Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| 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:2263/57478 Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent Focke, Walter Wilhelm u29110875@tuks.co.za Ferreira, Ignatius Van Wyk UCTD Micro-encapsulation Zein Geraniol Wintergreen oil Controlled release Aphid Engineering, built environment and information technology theses SDG-02 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Engineering, built environment and information technology theses SDG-15 Dissertation (MEng)--University of Pretoria, 2016. Microencapsulation of geraniol and wintergreen oil by the maize protein, zein, was investigated. The efficiency of encapsulation, the morphology of micro-particles and the controlled-release kinetics of the geraniol-zein system were studied. The main findings were the following: ? Geraniol-to-zein mass ratios lower than unity showed very low particle yields. At ratios higher than unity an abrupt increase in particle yield was observed. It reached values as high as 85%. Concurrently high geraniol mass fractions up to 78% were realised. This unusual behaviour is proposed to be attributed either to the inversion of the zein globular structure driven by an increase in the hydrophobicity of the surrounding medium or to the increased phase separation kinetics of the geraniol. ? Insignificant particle yields for the wintergreen oil-zein system may be attributed to the high polarity of methyl salicylate. ? Geraniol and wintergreen oil-containing micro-particles had a spherical geometry prior to lyophilisation. Scanning electron and confocal microscopy revealed that the geraniol-zein micro-particles can be classified as reservoir systems. Release kinetics approaching zero-order release, consistent with a glassy reservoir system, were observed. ? Kinetic modelling predicts that 80% of encapsulated geraniol can be released over a period of 17 days at 20 ?C. ? The results mean that the geraniol-zein microcapsule system holds promise and that it should be possible to produce it for large-scale, sustainable agricultural use as an aphid repellent. It is recommended that the release kinetics of the geraniol-zein system be studied in an aqueous environment and that other polar biopolymers be investigated. tm2016 mi2026 Chemical Engineering MEng Unrestricted SDG-02: Zero hunger SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production SDG-15: Life on land 2016-10-27T07:28:29Z 2016-10-27T07:28:29Z 2016-09-01 2016 Dissertation Ferreira, IVW 2016, Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/57478> S2016 http://hdl.handle.net/2263/57478 en © 2016 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 | UCTD Micro-encapsulation Zein Geraniol Wintergreen oil Controlled release Aphid Engineering, built environment and information technology theses SDG-02 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Engineering, built environment and information technology theses SDG-15 Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent |
| title | Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent |
| title_full | Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent |
| title_fullStr | Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent |
| title_full_unstemmed | Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent |
| title_short | Characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent |
| title_sort | characterisation of zein microcapsules with encapsulated geraniol or wintergreen essential oil for controlled release as an aphid repellent |
| topic | UCTD Micro-encapsulation Zein Geraniol Wintergreen oil Controlled release Aphid Engineering, built environment and information technology theses SDG-02 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Engineering, built environment and information technology theses SDG-15 |
| url | http://hdl.handle.net/2263/57478 |