Control of olive oil adulterated by soybean oil in a population where low olive oil consumption is an issue. A case study in Brazil

Abstract

The objectives of this work were to evaluate the ability of spectroscopic techniques to distinguish unadulterated and adulterated olive oil (OL) and to investigate consumers perception of adulterated OL samples by sensory tests in a population with low OL consumption. The adulterated OL samples were prepared with the addition of soybean oil (SO) in varying concentrations of 5 to 50% (v v-1). Samples were characterized using Fourier transform infrared (FTIR) spectroscopy and ultraviolet-visible (UV–visible) absorption spectroscopy. The capability of spectroscopy techniques to distinguish unadulterated and adulterated OL was evaluated by using a chemometric tool, principal component analysis (PCA). A questionnaire about the frequency of OL consumption was used. Multiple comparison and hedonic tests were used to discriminate and evaluate the acceptance of the adulterated OL samples. FTIR and UV–visible spectroscopy coupled with PCA proved to be good instruments to be used to distinguish OL samples intentionally adulterated with the addition of 5, 10, 15, 20, 30, 40, and 50% SO, and have great potential for classification of adulteration involving OL. The results confirmed that this group of Brazilian consumers has low OL consumption. Consequently, there was low discrimination of adulterated OL and they had the same acceptance as unadulterated and adulterated OL.