Changes in Sensitivity to Mechanical Damage in Relation to Cultivar, Maturity, Degreening and Storage

摘要

Previously we showed that fruit respiration rates may be used as a physiological marker of mechanical damage in 'Clemenules' Clementines. The objective of this work was to use this marker to determine the specific impact of some agronomical and technological processes. We determined the differences in sensitivity between cultivars ('Clemenules ','Hernandina' and 'Valencia Late '). Additionally, for 'Clemenules' the specific sensitivity of the fruit in relation to initial maturity (external colour), degreening and storage duration was investigated. External colour was determined as the IC index of each fruit with a colorimeter in L * a * b * coordinates. Degreening was carried out with exogenous ethylene following the standard procedure used in packing houses. The effect of storage duration was determined on fruit stored for 30 days at 5°C. Cultivar differences were as expected with fruit with thicker rind exhibiting lower sensitivity to mechanical damage. In Clemenules, a significant inverse relationship was found between the IC index and the sensitivity of the fruit to damage indicating that the more immature (greener) fruit were more sensitive to mechanical stress. Degreening did not increase the sensitivity to mechanical damage and the sensitivity decreased significantly during storage. The minimum sensitivity was found after 7 days of storage and remained at that level during the remaining storage period.