Effect of extraction systems and cultivar on the quality of virgin olive oils

P>This research was carried out to compare the effects of two industrial scale processes (super press and triple phase systems) and a traditional Tunisian family-sized operation with laboratory milling for two varieties of olives: Chemlali and Chemchali. Analyses of the effect of the extraction system, on the oils' characteristics, revealed statistically significant differences in some parameters, mainly in antioxidant compounds (P < 0.05). Major fatty acids presented significant differences (P < 0.05) with respect to the cultivar kind (55.93% vs. 72.21%). Oxidative stability of Chemchali was nearly two times higher than Chemlali (94.58 vs. 50.37 day kg(-1)). Results appear to confirm the general consensus that Chemchali oils are of much higher quality compared with the tolerable quality of Chemlali. The traditional method is a valid form of producing high quality oil with very high stability (48.87 and 109.07 day kg(-1) for Chemlali and Chemchali oil, respectively). However, industrial mills showed that triple-phase scale could cause considerable loss in polyphenols. Finally, olive oil quality is mainly dependant on the quality of the olives and on the extraction method.