Avocado (Persea americana Mill.) quality changes in response to low-temperature storage

Abstract

Avocado (Persea americana Mill. cv. Hass) fruit were stored at 2, 5, and 8 °C for four weeks to determine maximum cold-storage life. Skin colour, fruit firmness, mesocarp appearance, pectinmethylesterase (PME), polygalacturonase (PG), and cellulase (CX) activity were determined weekly during cold storage, and three times a week during subsequent transfer to 22 °C. Fruit held at 2 °C remained hard green during four weeks, and ripened normally upon removal to 22 °C. At the two higher temperatures fruit ripening started during storage. At 5 °C, ripening commenced during the fourth week of storage, and minor mesocarp discolouration was observed at full ripeness at 22 °C. Fruit held at 8 °C ripened after two weeks in storage, resulting in more intense mesocarp discolouration and vascular browning at full ripeness, upon transfer to 22 °C. For current Australian commercial storage of avocados cv. Hass, 7 °C is too warm, and may be reduced to 2 °C for preclimacteric fruit. Results indicate that fruit held at 2 °C can be stored for at least four weeks, and possibly five weeks without injury.