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 < 0.05), compared with control untreated fruits. Conclusion. 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. La qualité des olives a été mesurée périodiquement par l'évolution de la couleur de la peau, ainsi que par la fermeté de la chair, la perte de poids et la détérioration des fruits. Résultats et discussion. Généralement, le stockage des olives à (5, 10 et 20)°C a entraîné la diminution de la fermeté de chair, mais le ramollissement du fruit a été plus rapide pour les fruits stockés à (20 et 10)°C que pour ceux placés à 5°C. Les olives stockées pendant 60 jours à 5°C n'ont montré aucun symptôme des dommages dus au froid quel qu'ait été le cultivar. Les olives des différents cultivars ont gardé une chair ferme satisfaisante pendant 60 jours à 5°C, 30 jours à 10°C et 15 jours à 20°C. Après 60 jours de stockage, le développement de la couleur rouge de la peau a peu progressé dans des fruits stockés à 5°C, mais il a présenté des différences significatives aux autres températures. Cepen...

Effects of the ethylene-action inhibitor 1-methylcyclopropene on postharvest quality of non-climacteric fruit crops

“…To the best of our knowledge, only a single report has been published regarding effects of 1-MCP on postharvest quality of green olives, in which Ramin (2007) exposed different green olive varieties to 1-MCP at 0.45, 0.9 or 1.8 mL L À1 and found that this treatment significantly reduced fruit softening and delayed changes in peel color and yellowing in a concentration-dependent manner. Overall, Ramin (2007) concluded that exposure to 1-MCP at 0.9 and 1.8 mL L À1 enabled extension of the postharvest storage period of 'Conservolea', 'Mission', and 'Blady' green olives from 60 days to 15 weeks at 5 C.…”

Changes in volatile organic composition of olive oil extracted from cv. ‘Leccino’ fruit subjected to ethylene treatments at different ripening stages

“…Additional evidence comes from trials using the ethylene inhibitor 1‐methylcyclopropene (1‐MCP), a compound reported to affect specific ripening‐related processes in several non‐climacteric fruits 9 . With regard to olives, studies indicate that pre‐harvest application of ethylene inhibitors (ReTain and 1‐MCP) on green olives prevented skin coloring and reduced fruit softening, indicating a possible involvement of ethylene in olive ripening 10–12 …”

Hormonal Content and Gene Expression during Olive Fruit Growth and Ripening

“…However, while information regarding ethylene metabolism in olive fruits is limited, several studies have tracked fruit respiration during olive fruit ripening [30][31][32][33][34], in some cases, reporting contradictory results. Indeed, ethylene is effective in olive fruits, given that the ethylene inhibitors, 1-methyl cyclopropropene (1-MCP) or 1-amino ethoxyvinyl glycine (AVG), can reverse the ethylene responses, but the impact of these treatments or of exogenous ethylene reportedly depend on the olive cultivar [34][35][36][37][38][39]. Moreover, the level of ethylene precursor, 1aminocyclopropane-1-carboxylic acid (ACC), rises as olive fruit ripens [25], thus suggesting differential fruit ACC levels and ethylene sensitivity between olive cultivars.…”