CONTRIBUTION TO THE STUDY OF A TRADITIONAL OLIVE OIL EXTRACTION PROCESS AS APPLIED IN KABYLIA REGION (NORTHERN ALGERIA)

Abstract

In some municipalities of Kabylia region (northern Algeria), the traditional olive oil (OO) extraction process includes direct solar drying (DSD) of whole fruits as preliminary operation unit. The present work is a contribution to the study, for the first time to our knowledge, of this traditional process in terms of: i) drying ability of olive fruits evaluated throughout water removal rate (WR, % of initial olive weight (IOW)) and ii) some basic quality characteristics (specific absorbance at 232 nm (K232), free acidity, etc.) of resulting OO. For comparison purposes, solar tent drying (STD) as an attempt to improve the DSD, and hot air drying were also considered. The results obtained show that the olives treated by SD at an average temperature of 34°C and a relative humidity of 13-16% reach a WR of about 40% (against 30% ) and give a better oil with a free acidity of 0.74% compared to 1.10 and 2.36% for olives treated by STD (at 46 °C and RH = 10%) and undried olives treated in a modern oil mill, respectively. At last, solar drying makes the extraction process more eco-friendly, considering the low rate (0-0.05 L/kg fresh olive fruits) of olive vegetable water (OVW) during the OO extraction process. So, it is strongly hoped that this study will contribute to the further development of this research axis.