Physicochemical characterization and fatty acid composition of olive seed oil from the Moroccan Picholine variety

Abstract

The preparation of table olives represents an important economic and social activity in the Mediterranean region, notably in Morocco. This sector generates large quantities of solid pollutants such as olive stones. ‘Moroccan Picholine’ is the most widely cultivated olive variety in Morocco due to its high adaptability as it known for its olive and oil productivity. The objective of this work is to extract the oil from the seeds of olive stones, determine its physicochemical parameters and study its fatty acid composition from the Moroccan Picholine. The seeds were obtained by crushing the stones and isolating the cellulose part, and oil was extracted from the olive seeds using the standard Soxhlet method. A series of indices have been determined in the course of the work, such as free acidity, the peroxide index, the specific extinction coefficients K232 and K270, the total phenol content and the unsaponifiable matter content. The results showed that the oils extracted from olive seeds (a by-product of table olive processing units) have an oil yield ranging from 26.5 to 43.6 %, an acidity between 5.16 and 7.87 % and normal peroxide values from 10.15 to 12.31 Meq O2/kg. In addition, olive seed oils contain high levels of phenols varying from 6.27 to 11.82 g EAG/kg. On the other hand, gas chromatographic analysis shows that this oil is of the oleic, linoleic type. The main fatty acids are, in order of importance, oleic acid (67.1-68.5%), linoleic acid (18.9-20.6%), palmitic acid (7.8-8.2%). All these results show that olive seed oil is a new source of vegetable oil for different sectors.