NIR prediction of fruit moisture, free acidity and oil content in intact olives

Abstract

In this work, the prediction of olive fruit and virgin olive oil quality parameters through the direct measuring of the fruit using near infrared spectrometry (NIRS) has been investigated and the effectiveness of a portable spectrometer has been assessed. Models and calibration tests were developed using both the hexane-isopropanol extraction of individual olive fruits, and the Soxhlet extraction of olive paste. The parameters analyzed were the free acidity in olive oil, oil yield from physical extraction, oil content referring to fresh weight, oil content referring to dry matter and fruit moisture. The results indicate a good predictive potential with both methodologies and serve to encourage improvement in the obtained models through the enlargement of the calibrations. Fruit moisture prediction models showed high accuracy.