Total phenol content and chilling injury of normally-or deficit-irrigated fresh green olives during storage

Abstract

The effect of deficit irrigation of olive trees on fruit total phenol content and chilling injury during cold storage was examined. 'Konservolea' and 'Chondrolia' olive trees were irrigated based on the farmer's decision (control, exceeding 100% evapotranspiration) or deficit irrigated during stone hardening and final flesh swelling (irrigation water around 50% of control). Green olive fruit quality was evaluated at harvest and every week plus 1 day shelf life during 4 or 5 weeks storage at 5°C and included skin color, flesh firmness, % flesh dry matter, total phenol content and chilling injury (CI) symptoms. CI was subjectively evaluated as discoloration of flesh and skin due to injury and not due to ripening. In 'Konservolea' olives, skin color darkened after long storage due to internal CI (flesh browning), while there were no significant differences in total phenol content and CI during most of the measurements in fruits from control or deficit irrigated trees. In contrast, total phenol content in deficit irrigated 'Chondrolia' olives was higher at harvest and until the development of significant CI than control irrigated fruit, while a similar trend was found in CI early in storage between the two treatments. In the same cultivar, fruit total phenol content decreased with time in cold storage as severe CI symptoms appeared. 'Konservolea' green olives had lower total phenol content and sensitivity to low temperature storage compared to 'Chondrolia' green olives. These data could relate olive fruit total phenol content to CI sensitivity during cold storage.