Effects of storage temperatures and 1-MCP treatment on postharvest quality of green olives.

Abstract

Introduction . Olive processing in producing countries, such as Iran, is often not well synchronized with crop harvests due to the number and size of the oil-extraction facilities. After harvest, olives might be piled in heaps and stored at ambient temperatures for up to several weeks and, during this period, the greatest deterioration takes place. Therefore, the green olive processing industry is interested in the use of an alternative to the above pre-processing storage method for fresh olives. Materials and methods . Green olives cvs. Blady, Conservolea Mission and Shengeh were harvested at the mature green stage and stored at (5, 10 and 20) °C for 10–15 weeks to evaluate their postharvest physiology and quality changes. In the second year of the experiment, olives were treated with 1-MCP at concentrations of (0.45, 0.9 and 1.8) µL·L–1 at 20 °C for 24 h and stored at 5 °C. Olive quality was measured periodically for skin color, fresh firmness, mass loss and fruit deterioration. Results and discussion . Generally, storage of olive fruits at (5, 10 and 20) °C caused a decrease in flesh firmness, but fruit softening was faster in fruits stored at (20 and 10) °C than in fruits at 5 °C. Olives stored for 60 d at 5 °C showed no symptoms of chilling injury whatever the cultivar. Olive cultivars retained satisfactory firm flesh above 2 kg for 60 d at 5 °C, 30 d at 10 °C and 15 d at 20 °C. After 60 d of storage, red skin color development did not progress much with fruits stored at 5 °C, but there was a significant difference with the other temperature treatments. However, cv. Shengeh developed red skin color greater and sooner than other cultivars did. In the second year of the experiment, 1-MCP treatment effectively reduced loss of firmness for fruits stored at 5 °C for 15 weeks. Application of (0.9 and 1.8) µL 1-MCP·L-1 was sufficient to delay significantly olive softening and color changes (P . Conservolea, Mission and Blady olive cvs. can be stored for up to 60 d at 5 °C and this could be extended to 15 weeks when fruits are treated with (0.9 and 1.8) µL 1-MCP·L-1 before storage.