Fourier transform infrared spectroscopy combined with chemometrics for discrimination of Curcuma longa, Curcuma xanthorrhiza and Zingiber cassumunar
Turmeric (Curcuma longa), java turmeric (Curcuma xanthorrhiza) and cassumunar ginger (Zingiber
cassumunar) are widely used in traditional Indonesian medicines (jamu). They have similar color for their
rhizome and possess some similar uses, so it is possible to substitute one for the other. The identification
and discrimination of these closely-related plants is a crucial task to ensure the quality of the raw materials.
Therefore, an analytical method which is rapid, simple and accurate for discriminating these species
using Fourier transform infrared spectroscopy (FTIR) combined with some chemometrics methods was
developed. FTIR spectra were acquired in the mid-IR region (4000–400 cm1). Standard normal variate,
first and second order derivative spectra were compared for the spectral data. Principal component
analysis (PCA) and canonical variate analysis (CVA) were used for the classification of the three species.
Samples could be discriminated by visual analysis of the FTIR spectra by using their marker bands.
Discrimination of the three species was also possible through the combination of the pre-processed FTIR
spectra with PCA and CVA, in which CVA gave clearer discrimination. Subsequently, the developed
method could be used for the identification and discrimination of the three closely-related plant species.