Effect of the Solvent and the Sample Preparation on the Determination of Triterpene Compounds in Two-Phase Olive-Mill-Waste Samples

A simple and rapid extraction method has been employed to determine several value-added compounds, mainly triterpenes, in two-phase olive-mill-waste samples. The compounds were extracted with methanol or ethyl acetate, and the initial fresh samples were treated for classic techniques such as drying, drying and oil extraction, and drying and sifting of the olive stones. For the identification and quantitation of the compounds, an ultra performance liquid chromatography-mass spectrometry method was employed. The best results of the triterpenic compound content were achieved by extraction with methanol from the fresh sample for the oleanolic and ursolic acids, and erythrodiol and uvaol; and from the dried-extracted sample for the maslinic acid. Conversely, the best results for the linoleic acid content were reached by extraction with ethyl acetate from the dried-sifted sample. These are remarkable processes that make the solid wastes from the olive-oil industry reach a high added value.