Estimation of main chemical content of nutmeg oleoresin by using near infrared spectroscopy

Abstract

Determination of the main chemical content of nutmeg oleoresin is usually carried out by the GCMS method that time-consuming and expensive. It is required a faster and cheaper method for the determination of chemical contents of nutmeg oleoresin. The purpose of this study was to estimate the main chemical composition of Banda nutmeg oleoresin by NIR Spectroscopy. Transflectance of nutmeg oleoresin were measured by the NIR spectrometer. The samples were then subjected to composition analysis using GCMS. The transflectance spectra were processed using some data pretreatments, and the calibration between transflectance and chemical composition were carried out by using Partial Least Square (PLS) and Principle Component Regression (PCR) method. The best estimation for myristicin by NIRS was obtained using original spectra and 3 factors of PLS ( r=0.95, SEC=1.56%, SEP=1.71%, CV=10.18%, RPD = 2.60, and consistency of 91%). The best estimation by NIRS for myristic acid was also obtained using original spectra and 5 factors of PLS ( r=0.95, SEC=3.94%, SEP=3.82%, CV=32.47%, RPD = 2.75, and consistency of 103%). Whereas for safrole was obtained by using data pre-treatment of de-trending and 7 factors of PLS (r = 0.98, SEC=0.08%, SEP = 0.10%, CV =10.87%, RPD = 3.82, and consistency of 82%).