SALVIA OFFICINALIS L. ESSENTIAL OIL AND CARNOSIC ACID ANALYSIS BY MEANS OF NIR SPECTROSCOPY

This paper reports the results of a research aimed at investigating the applicability of the NIRS technique to the quantitative determination of sage quality traits, such as the content of carnosic acid, essential oil content and composition. 143 samples were analysed by means of two NIR spectrometers (a FOSS dispersive spectrometer and a mobile ZEISS spectrometer equipped with a photo diode detector), in comparison with a reference method, based on solvent extraction followed by gas-chromatography (essential oil), or liquid chromatography (carnosic acid). Reference essential oil content ranged form 8.6 to 31.3 ml kg^-1 d.m., with α- and β-thujone, camphor and 1,8-cineole as main components, while carnosic acid content was 8.6-39.9 g kg^-1 d.m. After spectra correction and wavelength selection, the application of modified partial least square regression (MPLS) allowed good NIR calibration for the analysis of carnosic acid and essential oil content and composition.