2. Methodology
2.1. Fruit source and ripening
Unripe green ‘Hass’ avocado fruit were harvested from three growers
in the North Island, New Zealand, during March 2011 (late maturity).
Fruit were commercially packed and transported to the Plant & Food
Research laboratory in Auckland within 4 days of harvest and held in
cool storage (5 °C) for 3 weeks. Fruit were ripened using 100 μLL
ethylene for 24 h at 20 °C and allowed to soften to the target fruit firmness.
Fruit firmness was measured using Aweta AFS (AWETA™Impact &
Acoustic Firmness System, Nootdorp, Holland), and fruit were selected
in the range of 20–26 Acoustic Index (AI) (equivalent to 0.6–0.8 kgf
Effegi puncture 8-mm probe), or “firm-ripe” on the hand-firmness
scale (rating of 3.5–4) (White, Woolf, Hofman, & Arpaia, 2005).
2.2. Sample preparation
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