Application of Two-Dimensional NIR-MIR Correlation Spectroscopy in Identifying Adulterated Sesame Oil

A method for identifying adulterated sesame oil using two-dimensional NIR-MIR correlation spectroscopy was proposed. 40 pure sesame oil samples and 40 adulterated sesame oil samples (with volume fraction of adulterating corn oil varying from 3% to 60%) were prepared. And NIR and MIR spectra of all these samples were collected. The synchronous 2D NIR-MIR (4 540-6 000 cm^-1 vs. 650-1 800 cm^-1) correlation spectra of these samples were calculated to construct N-way partial least squares discriminant analysis (NPLS-DA) model to identify adulterated sesame oil. The NPLS-DA models based on normalized synchronous 2D NIR and 2D MIR correlation spectra, were also constructed and their performance of discrimination to identify adulterated sesame oil were compared. It was found that the rates of accuracy of discrimination of the above mentioned 3 NPLS-DA models for the prediction set were 96.3%, 92.6%, 96.3%, respectively.