A COMPARATIVE-STUDY OF UV SPECTROPHOTOMETRIC METHODS FOR DETECTION OF OLIVE OIL ADULTERATION BY REFINED OILS

UV spectrophotometric measurements on hundreds of virgin olive oils and refined vegetable oils have shown that a previous method for evaluating the absorption maxima at 315 nm by calculation an Rs value (ratio of slopes of absorption curve in both sides of 315 nm) may lead to false conclusions concerning possible adulteration of virgin olive oils by refined olive, olive residue or seed oils. It was found that ΔK3154% values, obtained directly from the UV spectra, are much more reliable estimates of conjugated tetraene absorption at 315 nm, without affecting the sensitivity of the method. © 1990 Springer-Verlag.