Oxygen heterocyclic compounds (OHCs) in lemon oils are important markers in targeted HPLC analyses for authentication

Lemon oils are broadly used as flavoring agents in beverages, foods, cosmetics and pharmaceuticals, yet the adulteration of natural, particularly cold pressed lemon oils is very common in the industry due to its unmet demand and high cost. Nowadays, most quality control (QC) analysis of lemon oils is conducted by gas chromatography (GC) analysis, which is far from a reliable method. Oxygen heterocyclic compounds (OHCs) in non-volatile fraction are gaining increasing attention in authentication process because of the nearly finger-printing profiles of OHCs in cold pressed citrus essential oils. Our goal in this study was to identify OHCs using high performance liquid chromatography (HPLC) in lemon oils, establish OHC profiles, perform stepwise logistic regression analysis (SLRA) and build effective predicting model and further determine adulterated lemon oils by referencing the OHC profiles and established models. After HPLC analyses, profiling and SLRA modeling of 154 OHCs samples of industrial lemon oils, we found that the combination of isopimpinellin and total OHC concentration are essential and robust predictors to differentiate authentic samples from adulterated lemon oils with a success rate of 98% from the 5-fold cross validation. This study provided a reliable and efficient method in determining the authenticity of lemon oils.