Desenvolvimento de método para determinar adulteração de azeite de oliva com óleo de canola por espectroscopia no infravermelho médio associada à calibração multivariada

Abstract

Among the edible vegetable oils sold worldwide, the olive oil (Olea europaea sativa) is one of the most important and oldest in the world. The practice of selling a product mixed with pure olive oil allows that some manufacturer exert an unfair competition in the market, achieving more competitive prices for their product, as well as harm the consumer who buys the mixture as if it was olive oil. So, this study aimed to evaluate qualitatively and quantitatively the purity of olive oil extra virgin olive with canola oil by infrared spectroscopy. Prepared mixtures of olive oil and rapeseed oil in the proportions of the 100.00 0,00% (m / m), in duplicate. The spectrum were obtained with infrared spectrophotometer Perkin Elmer, Spectrum 65 model with accessory attenuated total reflectance in the range 650-3500 cm-1, with a resolution of 4 cm -1, being held 40 scans for spectrum acquisition. For each duplicate sample spectra were obtained. The calibration was performed with the elimination of outliers, on the basis of samples with leverage, the value found for the RMSECV (Root Mean Square Error of Cross Validation) was 7.8144, and the value of the correlation coefficient of 0.9188. Anomalous values were removed and the final value of the square root of the cross-validation average error was 6.952 and the value of the correlation coefficient of 0.9353, thus the model showed reasonable predictive capacity with lower correlation coefficient compared to the literature.