Rapid and Non‐Destructive Quantification of Trace‐Level Lignans in Sesame Oil Using <scp>FT</scp> ‐ <scp>NIR</scp> Spectroscopy and Chemometric Modeling

ABSTRACT Lignans are bioactive polyphenols in sesame oil that contribute to its antioxidant and metabolic health benefits. Their composition changes drastically during roasting and refining, but conventional methods such as HPLC–UV are time‐consuming and require organic solvents. Here, we established a rapid and non‐destructive near‐infrared (NIR) spectroscopic method coupled with partial least squares regression (PLSR) to simultaneously quantify six lignan species—sesamin, sesamolin, episesamin, diasesamin, sesaminol, and sesamol—in sesame oil. A total of 100 samples, including both roasted and refined oils, were analyzed. Reference data were obtained by HPLC–UV, and PLSR models were constructed using second‐derivative NIR spectra. The models achieved excellent predictive accuracy ( R 2 = 0.970–0.996; RMSE = 0.0008%–0.020%), even for trace‐level lignans such as sesamol (0.005%–0.03%) and diasesamin (&lt; 0.04%). The approach successfully distinguished structurally similar lignans and revealed spectral regions (around 7400 cm −1 ) linked to processing‐induced compositional changes. The proposed method provides a powerful, solvent‐free platform for rapid lignan profiling, allowing analysis within minutes without sample pretreatment, and offers strong potential for industrial quality control and process monitoring.