Metabolomics-Based Identification of Bleached Shellac in Liquid Fruit Wax

The purpose of this study was to identify whether liquid fruit waxes could be added with bleached shellac. The compounds of bleached shellac from different sources were analyzed by targeted metabolomics based on liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) combined with liquid chromatography with evaporative light scattering detection. Twelve target compounds were selected by multivariate statistical analysis including unsupervised principal component analysis (PCA) and supervised partial least squares discriminant analysis (PLS-DA). According to variable importance in the projection (VIP) value, five differential compounds and seven shared compounds were identified. Finally, the viability of this method in the detection of commercial liquid fruit wax products was verified using the shared compounds as biomarkers. These results showed that chromatography combined with mass spectrometry can identify whether bleached shellac could be added in liquid fruit wax.