Physico-chemical characteristics of olives and olive oil from two mono-cultivars during various ripening phases

The aim of this study was to find a correlation between the chemical and ph ysical parameters in the pulp of the olive, in order to identify the optimu m period during the 1998 harvesting period. For this reason various paramet ers have been monitored: the amount of oil in the pulp during the ripening phase obtained by solvent extraction with n-hexane, the acidity, the peroxi de value, the composition of fatty acids and the saturated/unsaturated fatt y acid ratio,, the composition of the unsaponifiable fraction, the antioxid ant capacity, the percentage of oil and the puncture test in two local Croa tian olive cultivars. The chemical parameters change during the ripening, i n order to control the oxidative changes of the cellular homeostasis of the whole lipophilic fraction that needs a stronger safeguard of the double bo nds against the oxidative stress. The modification of the physical characteristics, observed with the punctur e test, is related to the chemical changes which occur in the olive during the ripening period and the monitoring of these physical and chemical param eters can help to increase nutritional quality (as antioxidant capacity) an d allow for an acceptable amount of oil.