Qualitative Responses of “Nabali” Olive Oil to Harvesting Time and Altitudes at Sub-Humid Mediterranean

Abstract

To determine the effect of harvesting date and altitude on olive oil quality, a field experiment was done in two locations (400 and 700) meters above sea level. Olive fruits were sampled eight times and tested for oil quality characteristics. Oil content increased with delaying fruit harvest at high altitude. Oil content was greater at low altitude than high altitude. Oil quality was influenced by harvest date at both locations. Peroxide and acidity value increased significantly with late harvesting at both locations. Oil produced at lower altitude had higher acidities than oil produced at higher altitude. Saturated fatty acids (palmitic, stearic, and arachidic) and unsaturated (palmitoleic, oleic, linoleic, and linolenic) were influenced by harvesting dates and altitude, whereas palmitoleic acid was not affected at low altitude. Palmitic acid dominated the saturated fatty acids. The content varied with harvesting dates at both locations. Oleic acid was about 68% of the total fatty acids in oil produced from both locations. In general, a slight reduction in oleic acid was observed with advances in fruit ripening, whereas linoleic acid increased with fruit ripening at both altitudes. Linolenic and palmitoleic acids contents fluctuated among harvests. Oil produced from the higher altitude had a higher ratio of unsaturated to saturated fatty acid compare to oil produced at the lower altitude.

Keywords:

• Olives
• Cultivar Nabali
• Olive oil quality