The effect of harvesting date on the oil chemical properties of Nabali Baladi olive cultivar

The cultivated Olive (Olea europaea L.) is a long-lived evergreen tree native to the Mediterranean basin. ⁽¹⁾ It is the most important fruit trees produced commercially in most of the Arab countries .

Palestine is a major producer of olives with an annual average production  of 200,000 tons fruit  and 20000 tons of oil , this  qualifies Palestine to be  the 12th  in the world in  olive oil production.⁽²⁾ The total area of olive tree cultivated lands is about 100,000 hectare, which forms about 50% of total cultivated land, and about 80% of land cultivated in Fruit trees.⁽³⁾ Olive cultivation is concentrated in the northern provinces, particularly Nablus area of 18000 hectares, that follow the climate of the Mediterranean sea, hot, dry summers, rainy and cold in winter and an annual rainfall of 660 mm according to the Palestinian Meteorological data.  In addition, the Palestinian oil is considered to be of high quality among other olive oils in the world.⁽⁴⁾ There are several cultivars of  olive tree in Palestine but  the Nabali Baladi olive cultivar is the  most prevalent due to its ability to adapt to rain-fed agriculture and high oil content,  and most of the NB cultivar yield is processed for oil.⁽⁵⁾ Olive oil considered as essential consumptive food to the Palestinian people, with an estimated average annual per capita consumption of 3.6 liters.⁽⁶⁾ Olive oil is  rich in monounsaturated fatty acids, it is a major component of the Mediterranean diet, where it is attributed to protected from cardiovascular diseases compared to other parts of the world. Olive oil contains antioxidants such as pigments (chlorophyll and carotenoids) in addition to vitamin E and phenolic compounds and is considered one of the most components that influence the quality of the oil.⁽⁵⁾ The most important characteristic of olive cultivation in Palestine that its mainly organic farming and manual harvesting. Moreover modern olive presses extract olive oil, therefore, Palestine olive oil has a comparative advantage. Most of the  research recently emphasizes on the importance of olive oil with good international standard.⁽²⁾ Several factors affect oil quantity and quality, among these are cultivar, cultural practices , harvesting method, processing, handling and storage, and  harvesting time.  It is well known that oil quality is highly affected by the fruit maturity , oil quality  determined by the chemical and physical specifications based on standards and tests adopted by the IOC.⁽²⁾⁽⁴⁾  In spite of increase in the global demand for olive oil with high standards of quality, and the excess of oil production in Palestine, the ability of Palestinian olive oil competition in the global market is low and more research are needed to optimize the oil quality. The manipulation of the factors affecting oil quality will improve oil production with high standards.⁽⁵⁾⁽⁷⁾ Since the harvest date highly affects the oil chemical properties The main determinant of the oil quality⁽⁸⁾, therefore, the objectives of this research were :

1. To study the effect of different harvesting date on pomological properties of NB cultivar.
2. To study the effect of harvesting date on oil chemical properties of Nabali olive cultivar.
3. To study the effect of  antioxidants contents of olive oil on the stability of oxidation index of oil of NB CV during crop maturity.

Source:

Nihad Said Qasid Ibrahem 2016 , The effect of harvesting date on the oil chemical properties of Nabali Baladi olive cultivar.

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