Differentiation of French virgin olive oil RDOs by sensory characteristics, fatty acid and triacylglycerol compositions and chemometrics

The sensory and chemical characteristics (fatty acid and triacylglycerol compositions) of the five registered designations of origin (RDOs) of French virgin olive oils (‘Aix-en-Provence’, ‘Haute-Provence’, ‘Nyons’, ‘Nice’ and ‘Vallée des Baux de Provence’) (n = 539) were determined over a six year harvest period. The evaluation of fruity, bitter and pungent oils was insufficient for describing the RDOs, so it was necessary to complete the olive description with descriptive attributes (analogical describers) put forth by the tasters. All the isomers were taken into account to determine the fatty acid composition. The utilisation of propionitrile, instead of the mixture of acetone/acetonitrile, leads to a better separation of the triacylglycerols especially of the crucial pairs LOO + PLnP/PoOO, PLO + SLL/PoOP, SOL/POO. The fatty acid and triacylglycerol compositions make up a data bank of the five French RDOs. A linear discriminant analysis applied to the samples, described by 37 parameters, allow us to perfectly differentiate the RDOs: ‘Nyons’, ‘Nice’ and ‘Haute-Provence’. The ‘Aix-en-Provence’ and ‘Vallée des Baux de Provence’ RDOs, which are separate from the three other RDOs, are not completely differentiated. In fact, these two poly-varietal RDOs have two principal varieties in common: Salonenque and Aglandau which, at different levels, explains the established resemblances.