Postharvest handling practices and irradiation increase lenticel discolouration in ‘B74’ mango fruit

ABSTRACT

‘B74’ mango is a recently commercialised cultivar in Australia, with an appealing skin colour and firm fibreless flesh. However, fruit can develop lenticel discolouration (LD) after harvest, with loss of commercial value, especially after γ-irradiation as a disinfestation treatment. We hypothesised that postharvest practices could increase fruit sensitivity to LD and tested that by sequentially sampling fruit between the orchard and the end of the packing line over two seasons, followed by ripening without and with irradiation treatment. Exposure of 441–610 Gy γ-irradiation significantly increased the severity of LD by 6.8-fold in commercially picked and packed ripe fruit, reducing the proportion of marketable fruit from 98% to 2%, compared to irradiated fruit harvested directly from the trees and not exposed to de-sapping solution and packing operations. Also, LD increased progressively as the fruit passed through the harvesting and packing processes, and exposure to only bore water increased LD severity compared with no water contact. Results suggest that the typical de-sapping process used during harvesting is a major contributor to skin sensitivity to LD in ‘B74’ mango fruit, and that other packing operations involving wetting of the fruit have an additive effect on it. These effects are exacerbated if fruit is irradiated.

KEYWORDS:

• Mango
• postharvest handling
• irradiation
• lenticel discolouration

Acknowledgements

We thank Kerri Chandra for her assistance with statistical analysis, Barbara Stubbings and Leanne Taylor for their technical assistance, and growers for access to their orchards.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was funded by Horticulture Australia Ltd. [grant number M06005] using voluntary contributions from Harvest Fresh Fruits and matched funds from the Australian Government. The Queensland Government also co-funded the project through the Department of Agriculture and Fisheries.