ALLEVIATING CHILLING INJURY OF OLIVE DURING COLD STORAGE BY SAFE COMPOUNDS AFTER HARVEST

Abstract

Recently, there has been a great concern about increasing the yield and storage of many olive cultivars in Egypt and countries around the world. However, there is a lack of storage facilities to reduce the losses of olives. This study provide some safe treatments after harvest to extend the cold storage of olives, while reducing or mitigating the chilling injury of stored fruits. Treatments were done by dipping fruits of each used cultivar, namely Manzanillo and Toffahi in one of the treatment solutions which were, the control (water), Naphthalene Acetic Acid (NAA) at 100 or 200 ppm, Lisophos (LPE) at 200 or 400 ppm, putrescine at 1 or at 2 mM, in addition to benzyladenine (BA) at either 100 or 200 ppm. After dipping for 20 min, olives were left for air drying at room temperature (22 ± 2°C ) in foam plates, then stored in the cold store at (5 ± 1°C) and relative humidity of 95 %. Each solution contained the surfactant called Tween 20 at 0.05% (V/V). After each cold storage duration olives were left for 24 hrs on the bench at room temperature to warm up before assessing the physiological and chemical characteristics of fruits of each treatment. The results revealed that putrescine - treated fruits had higher chlorophyll content especially at 2 mM. Similar trend of results was obtained with LPE at 200 ppm or BA at 200 ppm. Meanwhile, there was a significant reduction of electrolyte leakage following the cold storage periods, especially with LOE at 400 ppm or putrescine at 1 mM when compared with the control. This study recommended dipping olive fruits after harvest and prior cold storage in Lisophos at 200 or 400 ppm or in putrescine solution at 1 mM to prolong the cold storage life and to reduce the injury of stored olives, while reducing their loss of quality.