Using a portable Raman-SORS spectrometer as an easy way to authenticate high oleic sunflower oil

Abstract

Nowadays, due to the high price of virgin olive oil, sunflower oil (SFO) is commonly used for cooking. Among its commercial types, High Oleic Sunflower Oil (HOSFO) is the most suitable because of its high oleic acid concentration, it excellent properties, which enhances its quality but also increases its price. To protect the consumer who buys a product at a higher price due to its added value in the form of a higher amount of oleic acid, it is necessary to authenticate the different commercial types of SFO throughout the processing and distribution chain. Therefore, the producer and the various distribution links up to the final point of sale and the official administration need tools to verify and ensure that the customer is buying the product he really wants. There is no study in the bibliography that deals with the differentiation (authentication) between the different types of SFO. In this article, using instrumental fingerprints obtained by Spatially Offset Raman Spectroscopy (SORS) and processed with different chemometric tools, it has been possible to authenticate the different commercial types of these oils. Chemometric analysis of the SORS fingerprint matrix revealed the natural grouping (HCA and PCA) of samples and the possible discrimination/classification based on characteristic Raman spectral regions associated with fatty acids occurrence. All developed models (PLS-DA, SVM, and SIMCA) showed reliable qualimetric performance (sensitivity, specificity, and low false positive/negative rates among others). They were able to authenticate HOSFOs effectively, but only SIMCA model allowed successfully discriminate among all types of SFOs.