Low Storage Temperatures as a Mean for Improving Quality, Extending Storage Life, Ripening of Hass and Fuerte Avocado Fruits

3 Abstract: Mature fruits of Hass and Fuerte avocado cultivars were stored at 5°C and 9°C for different periods before holding at 20°C for expanding its marketing duration as compared with control fruits only kept at 20°C. Fruit characteristics were evaluated at removal from cold storage and subsequent holding. Cold stored fruits of Hass and Fuerte cvs at 5°C had lower weight loss percent than occurred at 9°C at removal from any tested storage periods as well as after holding. Moreover, Hass fruits could withstand without any change in it s firmness up to 2-3 weeks at 5°C, meanwhile Fuerte fruits had no decline in its firmness during 5-7 weeks at 5°C. Respiration rate in both cultivars was greatly decreased due to cold storage especially at 5°C compared to control fruits. Holding of cold stored fruits although showed an increase in respiration rate, they were significantly lower than that occurred in control fruits. Color changes in fruits at cold storage (5°C and 9°C) were delayed for some weeks according to cultivars storage temperature, but color change in control fruits occurred after only one week. External damage did not appear during cold storage at 5°C up to 3 and 5 weeks in Hass and Fuerte cvs respectively. Cellulase activity was increased during cold storage and during holding in both cultivar, meanwhile pectinase activity may have limited role in this concern. From these results it can be concluded that cold storage at 5°C was better than storage at 9°C for expanding the market duration of avocado fruits.