An Integrated Authentication Analysis of Citrus aurantium L. Essential Oil Based on FTIR Spectroscopy and Chemometrics with Tuning Parameters

Citrus aurantium L. essential oil or Orange Oil (OO) has gained popularity recently due to its benefit for human health. An “economically motivated adulteration” can potentially occur to achieve more profit in the market. On the other hand, cheaper oil, such as Coconut Oil (CO), is commonly used as an adulterant. This study aims to perform an authentication analysis of OO by FTIR spectroscopy and chemometrics. The exploratory data analysis applied the principal component analysis at the initial stage of authentication analysis. Multivariate calibration of Principal Component Regression (PCR) and Partial Least Squares Regression (PLSR) was constructed from five pre processed FTIR spectral data. The PCR model using Standard Normal Variate (SNV) spectra was selected as the best prediction model for OO, whereas the PLSR model using SNV spectra was sorted for the best prediction model for CO. SNV spectra of OO, CO, and binary mixture of OO+CO was used to generate sparse partial least squares-discriminant analysis (SPLS-DA) model. Component number three with “keepX” for components 1, 2, and 3 were 1, 5, and 1, respectively, were selected along with the maximum distance approach to construct the discriminant model. The final sPLS-DA model explained the total variances of 94% with satisfaction separability of 100%, 97.8%, and 100% for OO, CO, and OO+CO, respectively. In conclusion, FTIR spectroscopy and chemometrics with tuning parameters can authenticate Citrus aurantium L. essential oil.