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Harvest and storage condition plus duration influencing internal browning and fruit quality of Rosy Glow
Objectives and Rationale
‘Rosy Glow’ is regarded prone to internal flesh browning. This study investigated tree age, harvest maturity, storage temperature, 1-methylcyclopropene (1-MCP) treatment and storage duration in CA as factors influencing ‘Rosy Glow’ internal browning.
Methods
Fruit were harvested at <40% and >50% starch breakdown (SB) for the harvest maturity trial (Trial 1) and <40% SB for the storage duration, temperature, 1-MCP (Trial 2) and tree age trial (Trial 3). Trial 1 and 3 fruit were stored for 7 months in CA (1% CO2 and 1.5% O2) plus 6 weeks in air at -0.5 °C and 7 days at 20 °C and evaluated after each period. Trial 2 fruit treated with or without 1-MCP, were stored at -0.5 °C or 2 °C and evaluated after 3, 5 and 7 months in CA plus 6 weeks in RA and 7 day shelf-life periods. Fruit numbers used in the trial were increased in the second season in order to decrease variability. The results therefore mainly focused mainly on the second season although both seasons are taken into consideration.
Key Results
Diffuse (DB), radial (RB), and combination (CB) as well as CO2 browning were observed in both seasons. Optimum harvested fruit (<40%) were less susceptible to DB and RB. 1-MCP treated fruit had a lower internal browning incidence and no tree age effect was observed (4th and 7th leaf). DB and RB were first observed after 5 months in CA plus 6 weeks RA at –
0.5 °C and increased with storage time and was highest after the shelf-life period. A weak (60%) correlation was observed with background colour and browning incidence after storage and shelf-life.
Key Conclusions of Discussion
Diffuse browning was the main type of browning present. Post-harvest maturity (>50% SB) played a significant role in ‘Rosy Glow’ browning development. Fruit quality was better retained at -0.5 °C than at 2 °C in the second season, while 1-MCP treated fruit quality was better maintained than control fruit over time. A large orchard influence was observed on ‘Rosy Glow’ browning. Ripening rates over time for various orchards and factors influencing ripening rate requires further investigation.
For Final Report, please contact:
anita@hortgro.co.za