Project Detail

Project Number

A-13-USH-PH12

Project Leader

E. Crouch

Institution

Stellenbosch University

Team Members

L. Schoeman, K. v. d. Merwe

Student(s)

J. Wonder Doe

Date Started

November, 2013

Date Completed

September, 2016

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