Effect of Harvesting in Different Ripening Stages on Olive (Olea europea) Oil Quality
The aim of the present study is to investigate the chemical and physical characteristics of the olive oil in different ripening stages of Manzanilla and Kalamata varieties to determine the optimum harvesting time of the olive fruits. The oil content was gradually increased due to the accumulation of synthesized oil during maturation process. The oil showed an unstable trend in the relation between the acid value and ripening stages. The peroxide values in all ripening stages were below the standard limit. The K values significantly decreased from S1 to S5 but still within standard limit. The moisture content very slightly decreased in maturity and declared that the maturity stages didnʼt significantly affect the moisture content. The iodine value was significantly decreased with ripening development. The saponification value was significantly decreased with developing of ripening stages. Refractive index values of Manzanilla and Kalamata oils were below the standard limit. Reddish stage (S4) of ripening showed the best physicochemical characteristics. All stages of ripening showed a high content of unsaturated fatty acid especially oleic acid. The total polyphenols and flavonoids level in early maturation stages higher than late maturation stages. The early ripening stages showed the highest antioxidant capacity while significantly decreased with the developing of ripening stages. Organoleptic scores descended along with advanced ripening stages of olive fruit. Finally, we can conclude that the reddish ripening stage (S4) is the best stage for harvesting of the olive fruits to get the high quality of oil.