DISCRIMINATION OF VARIETAL OLIVE OILS OF THE PORTUGUESE CULTIVARS COBRANÇOSA, MADURAL AND VERDEAL BASED ON THEIR FATTY ACIDS COMPOSITION

The fatty acid composition has been traditionally used to discriminate the different vegetable oils and confirm their authenticity. The aim of the present study was to check the possible use of the fatty acid profile to differentiate varietal olive oils of the three most important cultivars in Northeast Portugal (Cobranqosa, Madural and Verdeal). Fifteen varietal olive oils from each of the three cultivars were collected to achieve that goal. Fatty acids were determined, as methylesters, by HRGC. Methylesters; were prepared by transesterefication with BF3/methanol after saponification with methanolic KOH. The fatty acid pattern was performed with a Chrompack CP9001 equipped with a split-splitless injector, a FID and a 50m x 0,25 mull W. fused silica capillary column coated with a 0.19mum film of CP-Sil88 (Chrompack). The temperatures of injector, detector and oven were 230, 250 and 185degreesC, respectively. The results as shown by two-way Anova techniques and discriminant analysis demonstrate that C(16:1)c, C-17:1, C-18, C18:1C, C(18:2)cc and C(18:3)cc can be used to discriminate the origin of each of the three olive oils.