Physical and chemical behaviour of Nabali Mohassan single-cultivar olive oil during prolonged storage.

Background: The effect of storage time on the fluorescence emission intensity and physico-chemical properties of olive oil from the Palestinian cultivar Nabali Mohassan was investigated. Olive oil samples stored up to 7 years were obtained from different olive orchards in Palestine, where prolonged storage is still in use.

Results: As a result of oxidation, all fluorescent minor compounds (tocopherols, chlorophylls, pheophytins and phenolic compounds) of olive oil significantly decreased as the storage time increased, whereas viscosity increased (P < 0.