Sensing the Addition of Vegetable Oils to Olive Oil: The Ability of UV–VIS and MIR Spectroscopy Coupled with Chemometric Analysis

The aim of this study was to assess the ability of both UV–VIS and ATR-MIR spectroscopy to identify and quantify the addition of vegetable oils (canola and sunflower) to olive oil (artificial adulteration). The spectra of pure oils and mixtures was collected using an UV–VIS (200–800 nm) (1 cm path length) and an ATR–MIR instruments. This study showed that both UV–VIS and ATR-MIR spectroscopy can detect levels of adulteration above 10% due to their lower error values in prediction. However, both methods have difficulties to detect low levels of adulteration (less than 1%). Interpretation of the UV–VIS and MIR spectra indicated that differentiation between adulterated samples might be explained by the different fatty acids, products of the oxidation of lipids and change in the pigment profiles derived from the different oil samples. It was concluded that both UV–VIS and MIR spectroscopy might detect and quantify the level of addition of vegetable oils into olive oil.