Characterization and authentication of olive, camellia and other vegetable oils by combination of chromatographic and chemometric techniques: role of fatty acids, tocopherols, sterols and squalene

Fatty acids, tocopherols, sterols and squalene were analyzed by chromatographic-based techniques and were selected as variables to build a variety of classification models for the accurate characterization and authentication of olive, camellia oil and six other vegetable oils (soybean, corn, rapeseed, peanut, palm and sunflower). Different unsupervised and supervised chemometrics techniques, such as principal component analysis (PCA), linear discriminant analysis (LDA) and partial least squares discriminant analysis (PLS-DA), have been applied. In addition, the Kennard–Stone algorithm was used to select the training samples for the construction of supervised models. The discriminating power of different components was compared, and the results suggested that fatty acids are the most powerful in distinguishing vegetable oils, followed by tocopherols and sterols, and squalene contributed to the discrimination between olive and camellia oils despite their apparent similarities. This proposed method was straightforward and can be easily implemented to identify unknown oil samples.