A multivariate approach to qualify “Moroccan Picholine” virgin olive oil according to extraction and environmental factors

This paper describes the composition and quality characteristics of the “Moroccan Picholine” virgin olive oil (VOO) produced in Taza province (northern Morocco). Legal quality indices, pigments, total phenols, oxidative stability, and fatty acid composition were analyzed under the impact of three extraction systems (two phase [C2] and three phase [C3] centrifugation decanters and super-pressure [SP]) in three production sites (Bni Frassen, Bouchfaa, and Taza) during three consecutive crop seasons (2014, 2015, and 2016). All the assessed parameters were largely affected by the extraction system. Indeed, the two phase centrifugation system provided the better quality of VOO with the lowest values of free fatty acids and oxidation indices and the highest amounts of oleic acid, carotenoids, and total phenols therefore the greatest oxidative stability. Crop season and production site had only significant impacts on some parameters. VOO produced in 2015 from Bni Frassen was richer on total phenols hence presented lower values of peroxide value. Principal component analysis (PCA) showed a clear separation along PC1 (58%) between C2 with better VOO characteristics from both C3 and SP, while PC2 (11%) allowed a net distinction of VOO produced in 2014 from those in 2015 and 2016. Moreover, the oxidative stability of the assessed VOO was found strongly related to total phenol and carotenoid contents as well as oleic/linoleic ratio.