Diffuse-light absorption spectroscopy and chemometrics for discrimination and quantification of extra virgin olive oil adulterants

A selection of top-quality extra virgin olive oils with excellent nutraceutic properties was artificially adulterated by means of lower-grade olive oils commonly used in commercial counterfeits. The oil sample set was analyzed by means of diffuse-light absorption spectroscopy performed in the wide 400-1700 nm spectral range. A setup based on optical fiber technology was experimented, which made use of an optical fiber supercontinuum source. The spectroscopic library was processed by means of a Partial Least Squares regression for quantifying the adulterant concentration, followed by a Principal Component Analysis and Linear Discriminant Analysis for identifying the type of adulterant.