Ground-breaking comparison of target stable isotope ratios vs. emerging sesquiterpene fingerprinting for authenticating virgin olive oil origin

Abstract

This study presents a pioneering comparison of target stable isotope ratios analysis and sesquiterpene (SH) fingerprinting for authenticating virgin olive oil (VOO) geographical origin. Both methods were selected for being among the most promising targeted and untargeted approaches, respectively. These methods were applied to the same sample set of nearly 400 VOO samples, covering diverse harvest years, cultivars and producers. PLS-DA classification models were developed to differentiate between Italian and non-Italian VOOs, as well as VOOs from three closely located Italian regions. Isotopic models based on bulk δ¹³C, δ¹⁸O and δ²H achieved over 75 % classification accuracy in distinguishing Italian from non-Italian VOOs, while SH fingerprinting outperformed with over 90 % accuracy and greater sensitivity to regional differences, as assessed in external validation. This systematic comparison provides insights into the strengths and weaknesses of each method, and the results will guide future research to enhance their reliability in VOO geographical authentication.