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Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage

Thesis (MScAgric)--Stellenbosch University, 2026.

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Main Author: Ramos, Daniela
Other Authors: Crouch, Elke M.
Format: Thesis
Language:English
Published: Stellenbosch : Stellenbosch University 2026
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access_status_str Open Access
author Ramos, Daniela
author2 Crouch, Elke M.
author_browse Crouch, Elke M.
Ramos, Daniela
author_facet Crouch, Elke M.
Ramos, Daniela
author_sort Ramos, Daniela
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MScAgric)--Stellenbosch University, 2026.
format Thesis
id oai:scholar.sun.ac.za:10019.1/135914
institution Stellenbosch University (South Africa)
language English
last_indexed 2026-06-10T12:43:23.129Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2026
publishDateRange 2026
publishDateSort 2026
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/135914 Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage Ramos, Daniela Crouch, Elke M. Jooste, M. M. Crouch, I. J. Stellenbosch University. Faculty of AgriSciences. Dept. of Horticultural Science. Thesis (MScAgric)--Stellenbosch University, 2026. Ramos, D. 2026. Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/5b4345e8-588f-489b-b81d-cd9f42a6d483 Internal browning (IB) is a major post-harvest physiological disorder of ‘Cripps Pink’ apples that threatens the reputation of the Pink Lady brand in export markets. IB reduces fruit quality and typically develops after long-term storage. The disorder is multifactorial, influenced by pre-harvest temperatures, orchard factors and canopy position, as well as post-harvest storage technologies. Accordingly, this study had three objectives: (i) to assess the effects of pre-harvest temperature and orchard factors on IB, (ii) to investigate the influence of canopy position on IB incidence and associated fruit quality attributes, and (iii) to evaluate the efficacy of dynamic controlled atmosphere-chlorophyll fluorescence (DCA-CF) storage compared with controlled atmosphere (CA) storage in reducing IB after long-term storage. The study showed that orchard factors and temperatures during fruit development and ripening strongly influenced IB incidence. Radial browning (RB) was higher in high-yielding orchards, slightly higher in orchards where pre-harvest ethylene inhibitors were applied, and under warmer fruit development followed by cooler ripening conditions. Diffuse browning (DB) occurred mainly in cool seasons with low growing degree days (GDD), confirming its chilling-related nature. Combination browning (CB) was associated with rootstock, vigour and fruit size, but no clear climatic threshold was identified. Superficial and peduncular scald were most severe in vigorous canopies and in seasons with cooler early-season temperatures. CO2-related flesh and cavity disorders were most prevalent in orchards with vigorous or seedling rootstocks. Warmer conditions during fruit enlargement generally reduced CO2 disorder susceptibility, whereas cooler temperatures during early development or ripening increased risk. Overall, temperature-maturity interactions drove defect patterns, highlighting the need for refined climate-based models using more homogenous climate zones. DB and CB were not associated with specific canopy positions in free-standing trees; however inside-canopy fruit were more prone to RB and both forms of scald after long-term storage. This higher susceptibility likely reflects reduced light exposure and lower antioxidant capacity, limiting the fruit’s tolerance to storage stress. Inside fruit also had poorer blush development, firmness, TSS and TA than outside fruit. The results demonstrate that more open, modern canopy structures promote a more uniform fruit developmental environment and reduce within canopy variability. Post-harvest fruit from different canopy positions should be harvested and stored separately, as they differ physiologically and vary in their susceptibility to post-harvest disorders. The comparison of DCA-CF and CA storage showed that IB susceptibility was driven primarily by fruit physiological maturity at harvest rather than the storage technique employed. Extensive starch breakdown between harvest and pre-storage highlighted the need for accurate maturity assessment before low-oxygen storage. Fruit harvested post-optimum showed higher total IB under both CA and DCA-CF, whereas optimally mature fruit benefitted from DCA-CF through reduced superficial and peduncular scald, but this result was not consistent for IB types. Overall, effective IB management requires an integrated orchard-to-storage approach, including monitoring pre-harvest temperatures, accounting for orchard factors, separating fruit by canopy position, and applying strict maturity indexing before low-oxygen storage to maintain Pink Lady® quality. Masters 2026-04-15T07:27:15Z 2026-04-15T07:27:15Z 2026-03 Thesis https://scholar.sun.ac.za/handle/10019.1/135914 en Stellenbosch University 371 pages application/pdf Stellenbosch : Stellenbosch University
spellingShingle Ramos, Daniela
Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage
title Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage
title_full Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage
title_fullStr Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage
title_full_unstemmed Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage
title_short Internal Browning and other defects of ‘Cripps Pink’ apples – The Effect of Growing Region Temperature, Canopy Position and Dynamic Controlled Atmosphere - Chlorophyll Fluorescence on Fruit Quality After Long-Term Storage
title_sort internal browning and other defects of cripps pink apples the effect of growing region temperature canopy position and dynamic controlled atmosphere chlorophyll fluorescence on fruit quality after long term storage
url https://scholar.sun.ac.za/handle/10019.1/135914
work_keys_str_mv AT ramosdaniela internalbrowningandotherdefectsofcrippspinkapplestheeffectofgrowingregiontemperaturecanopypositionanddynamiccontrolledatmospherechlorophyllfluorescenceonfruitqualityafterlongtermstorage

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