Fatty Acid Compositions of Olive Oils from Six Cultivars from East and South-Western Algeria

Abstract

The aim of this work is to characterize olive oils from six algerian cultivars (Azeradj, n=4); Blanquette, n=7; Bouricha, n=2; Chemlal, n=5; Limli, n=3; Sigoise, n=1) by determining their fatty acid compositions. The fatty acid composition of oils is determined using gas chromatography of methyl esters obtained by transesterification of triacylglycerols with 2M KOH/MeOH. Fourteen fatty acids and squalene are identified in all the samples. Oleic acid (18:1ω9), palmitic acid (16:0), linoleic acid (18:2ω6) and stearic acid (18:0) are the major fatty acids commonly found in olive oils. Palmitoleic acid (16:1ω7), hypogeic acid (16:1ω9), oleic acid (18:1ω9) and cis-vaccenic acid (18:1ω7) are considered as separate entities by the European regulation, unlike the Codex Alimentarius which identifies them as a single component. Six minor fatty acids namely margaric acid (17:0), margaroleic acid (17:1ω8), arachidic acid (20:0), gondoique acid (20:1ω9), behenic acid (22:0) and lignoceric acid (24:0) are identified. These acids, although minor, are important for the characterization of cultivars. Oils of different cultivars are characterized by different fatty acid compositions. All the values of fatty acid compositions are in compliance with the regulations of the International Olive Oil Council and Codex Alimenta-rius. A radial plot enables the analysis and characterization of each variety as a morphotype by creating a morphogramme . The morphogramme is designed as a radial representation of each fatty acid (n=14) using an Excel ® spreadsheet, and each axis represents the change in the variable with respect to the mean. The morphotypes are real fingerprints of different oil cultivars. Thus, the oils of Azeradj, Blanquette, Chemlal, Limli and Sigoise cultivars have specific morphotype . The morphotype of the Bourricha cultivar is very similar to the Chemlal cultivar. In addition, the Blanquette morphotype is identical to that of the tunisian cultivar Chetoui. This mode of representation is particularly effective for the rapid visual identification of characteristics of olive oils.