Classification and analysis of citrus oils by NIR spectroscopy

A new NIRS method is introduced for the determination of valuable component s in various citrus oils. Spectra of grapefruit, orange, mandarin, lemon an d lime oils in the range from 1100 to 2500 nm have been registered. Applyin g principal component analysis to the spectral data a good separation of th e different fruit oil types can be achieved. The application of multivariat e statistics in conjunction with analytical reference data leads to good NI R calibration results. For the main components (e.g. limonene, gamma -terpi nene, sabinene) and general chemical-physical parameters (e.g. optical rota tion value, aldehyde content) standard errors are in the range of the appli ed reference method. The multiple coefficients of determination (R-2) for c omponents with an amount of more than 1.5% are generally > 0.95. Furthermor e reliable in-process methods for the determination of the individual nootk atone and aldehyde contents during the isolation and purification process f rom grapefruit and orange oil are presented, (C) 2000 Elsevier Science Ltd. All rights reserved.