Adulteration detection of essence in sesame oil based on headspace gas chromatography-ion mobility spectrometry

Sesame oil is a traditional and delicious edible oil in China and Southeast Asia with a high price. However, sesame oil essence was often illegally added to cheaper edible oils to counterfeit sesame oil. In this study, a rapid and accurate headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) method was proposed to detect the counterfeit sesame oil where the other cheap oils were adulterated with essence. Combined with chemometric methods including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and random forest (RF), authentic and counterfeit sesame oils adulterated with sesame essence (0.5%, w/w) were easily separated into two groups. More importantly, 2-methylbutanoic acid, 2-furfurylthiol, methylpyrazine, methional, and 2,5-dimethylpyrazine were found to be markers of sesame essence, which were used to directly identify the sesame essence. The determination of volatile compounds based on HSGC-IMS was proven to be an effective method for adulteration detection of essence in sesame oil.

Automated summary

In this study, a rapid and accurate method using headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) was proposed to detect counterfeit sesame oil adulterated with sesame essence. The chemometric methods successfully separated authentic and counterfeit sesame oils, while specific volatile compounds were identified as markers of sesame essence for direct identification. The determination of volatile compounds based on HSGC-IMS was proven to be an effective method for detecting essence adulteration in sesame oil.