Cold storage conditions affect ‘Shepard’ avocado fruit ripening and quality

Abstract

There has been little research into long storage of Shepard avocado. Simulated conditions for sea freight of Australian-grown fruit to key Asian markets were investigated. Thirteen storage treatments were applied to fruit of premium quality sourced from two commercial farms. Compared with the generally recommended 7°C, fruit stored at 5.5°C for up to 28 days were firmer at removal, slow to ripen, and had less severe flesh rots at the ripe stage. Compared with regular air storage (Air), controlled atmosphere (CA; 2% O2 and 5% CO2) decreased weight loss at removal, retarded ripening and, after 28 days of storage, reduced discrete patches on the skin of ripe fruit. However, CA storage also resulted in ripe fruit with more severe shrivel, stem end rot, and vascular browning. For 14 or 21 days at 5.5°C, Air resulted in the best overall quality of Shepard fruit. CA was comparatively advantageous after a 28-day storage in improving external quality at ripe. There was considerable variation between both farms in storage effects on fruit ripening and quality. Given the high variability in fruit chilling responses apparently dependent on preharvest factors, further research is warranted to elucidate these results and better evaluate risks under commercial sea freight conditions.