Rapid NIR determination of alkyl esters in virgin olive oil

The regulation of The European Union for olive oil and olive pomace established the limit of 35 mg(.)kg(-1) for fatty acids ethyl ester contents in extra virgin olive oils, from grinding seasons after 2016. In this work, predictive models have been established for measuring fatty acid ethyl and methyl esters and to measure the total fatty acid alkyl esters based on near infrared spectroscopy (NIRS), and used successfully for this purpose. The correlation coefficients from the external validation exercises carried out with these predictive models ranged from 0.84 to 0.91. Different classification tests using the same models for the thresholds 35 mg(.)kg(-1) for fatty acid ethyl esters and 75 mg kg(-1) for fatty acid alkyl esters provided success percentages from 75.0% to 95.2%.