THE USE OF GC-MS AND FTIR SPECTROSCOPY COUPLED WITH MULTIVARIATE ANALYSIS FOR THE DETECTION OF RED GINGER OIL ADULTERATION

Abstract

The ginger oil traded worldwide could come from various sources. Standard quality is the most critical aspect of ensuring customer safety. This study aims to develop an analytical method for red ginger oil (RGO) authentication. Chemical compositions of red ginger oil were determined by Gas Chromatography-Mass Spectrometry (GC-MS). The Fourier Transform Infrared Spectroscopy (FTIR) coupled with multivariate analysis (discriminant analysis (DA), partial least square (PLS), and principal component regression (PCR) were used to identify and quantify the adulterant. The total terpenoid compounds were 55.72%, with the percentage of monoterpenes at 34.29% and sesquiterpenes at 21.43%. E-Citral (19.01%), Z-Citral (14.82%), Geranyl Acetate (11.90%), Geraniol (9.56%), 1,8-Cineole (5.84%), and camphene (4.92%) were identified as the main constituents. The best PLS model for quantifying the level of palm oil in RGO was at the wavenumber 3100–2700 cm–1, while the region of 3100 – 2700 and 1850 – 650 cm–1 was suitable for detection of soybean adulterants. FTIR spectroscopy coupled with chemometrics produced accurate and fast authentication of red ginger oil without the used solvent. Then, the GC-MS technique could identify the chemical constituents present in the red ginger oil.