Articles
DYNAMIC CONTROLLED ATMOSPHERE STORAGE OF NEW ZEALAND-GROWN ‘HASS’ AVOCADO FRUIT
Article number
876_4
Pages
47 – 54
Language
English
Abstract
To obtain the maximum benefits from dynamic controlled atmosphere (DCA) storage, several parameters of operation need to be optimised.
These parameters include the time after harvest at which the lowest safe O2 level is first established (delay), the degree of back-off in O2 above the low O2 stress point (back-off), and the frequency of resetting the lowest safe O2 level during storage (frequency). The DCA operating parameters delay, back-off and frequency were investigated by storing Hass avocado fruit for 6 weeks at 5°C in DCA. Fruit were held in air for 48 or 96h after harvest before the initial lowest safe O2 level was established by backing-off by 0.2 or 0.8% O2. The lowest safe O2 level was reset every 10 d (repeat) throughout storage, or left as that achieved at the start of DCA (once). In addition, to determine whether the fruit response to the DCA operating parameters changes through the harvest season, fruit were harvested during the early (late October), mid (mid December) and late (mid February) periods of the harvest season.
Fruit quality following DCA was optimised by setting the DCA O2 level soon after harvest, backing-off to just above the low O2 stress point, and repeatedly re-setting the O2 level during storage.
The main effect of frequency was on skin colour and rots (fuzzy patches; FP) at the end of storage, and on the time to ripen after storage.
In contrast, the effects of back-off were on FP and diffuse flesh discoloration and delay on stem-end rot expression.
There were no major differences in the responses of fruit harvested at different times of the season to the DCA operating parameters.
It is concluded that for New Zealand-grown Hass avocados, DCA should be established within 2-4 days of harvest, backing-off to just above the low O2 stress point and resetting the lowest safe O2 level every 10 days.
These parameters include the time after harvest at which the lowest safe O2 level is first established (delay), the degree of back-off in O2 above the low O2 stress point (back-off), and the frequency of resetting the lowest safe O2 level during storage (frequency). The DCA operating parameters delay, back-off and frequency were investigated by storing Hass avocado fruit for 6 weeks at 5°C in DCA. Fruit were held in air for 48 or 96h after harvest before the initial lowest safe O2 level was established by backing-off by 0.2 or 0.8% O2. The lowest safe O2 level was reset every 10 d (repeat) throughout storage, or left as that achieved at the start of DCA (once). In addition, to determine whether the fruit response to the DCA operating parameters changes through the harvest season, fruit were harvested during the early (late October), mid (mid December) and late (mid February) periods of the harvest season.
Fruit quality following DCA was optimised by setting the DCA O2 level soon after harvest, backing-off to just above the low O2 stress point, and repeatedly re-setting the O2 level during storage.
The main effect of frequency was on skin colour and rots (fuzzy patches; FP) at the end of storage, and on the time to ripen after storage.
In contrast, the effects of back-off were on FP and diffuse flesh discoloration and delay on stem-end rot expression.
There were no major differences in the responses of fruit harvested at different times of the season to the DCA operating parameters.
It is concluded that for New Zealand-grown Hass avocados, DCA should be established within 2-4 days of harvest, backing-off to just above the low O2 stress point and resetting the lowest safe O2 level every 10 days.
Authors
J. Burdon, N. Lallu, G. Haynes, P. Pidakala, D. Billing, K. McDermott
Keywords
DCA, quality, chlorophyll fluorescence, HarvestWatch™, Persea americana
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