Gaseous ozone as a postharvest treatment: recent lessons from South Africa

Gaseous ozone decomposes to form free radicals, and has a wide range of antimicrobial properties.
Currently, gaseous ozone is largely viewed as a phytosanitary treatment as opposed to a complete postharvest treatment with the ability to minimize negative physiological and biochemical processes during storage and shelf-life.
However, emerging research has demonstrated that ozone treatments may trigger the synthesis of various secondary metabolites such as phenolic compounds and antioxidants.
Reduced ethylene accumulation has also been reported in fruits kept in ozonated storage chambers.
Currently, ozone does not form part of postharvest treatments used by the South African fresh produce industry.
With this knowledge, we have recently undertaken studies to assess the effect of gaseous ozone on selected fresh fruits.
The objective of this manuscript is to highlight some of our recent successes and shortcomings on the potential of gaseous ozone as a postharvest treatment.
Our first study investigated the effect of intermittent ozone treatments on the quality and shelf-life of ‘Keitt’ mangoes.
The findings have shown that mangoes exposed to ozone had delayed colour change, higher firmness retention, lower decay incidence and mass loss.
Moreover, gaseous ozone notably reduced the incidence of stem-end rot and anthracnose.
Superficial scald is one of the major postharvest physiological disorders affecting ‘Granny Smith’ apples.
Although various postharvest treatments have been developed, their effectiveness and costs prohibit their use by the apple fruit industry.
Thus, our second study assessed the effect of gaseous ozone on the superficial scald of apples.
The findings have shown that gaseous treatment of 24 h is effective in reducing scald during long-term storage.
Moreover, there was lower ethylene accumulation and higher colour retention in ozonated fruit.
These findings suggest that gaseous ozone has a great potential as a postharvest treatment.
It offers many benefits to the fresh produce industry as it is relatively cheap and does not leave residues of treated fruit.

IV Asian Horticultural Congress – AHC2023

A. Mditshwa, N.L. Bambalele, N.H. Gcabashe, S.Z. Tesfay, L.S. Magwaza

ozone, postharvest quality, shelf-life, mangoes, apples, superficial scald

https://doi.org/10.17660/ActaHortic.2024.1404.52