Profile chemical compounds and antioxidant activity of Korean commercial vinegars produced by traditional fermentation

Ultra-high-performance liquid chromatography coupled with linear trap quadrupole-orbitrap mass spectrometry (UHPLC-LTQ–Orbitrap MS) with multivariate statistical analysis was applied for the metabolite profiling and assessing antioxidant activity of ten commercial vinegars produced by traditional fermentation techniques. Totally, 28 metabolites including three organic acids, three phenolic acids, 11 flavonoids, nine lipids and fatty acids, 6-methoxymellein, and tyrosyl-valine, were identified in the ten vinegars. Using principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA), vinegar samples were differentiated based on raw materials used in their production. Based on the PC1 (42.10%) and PC2 (9.86%), mulberry fruit vinegar (OV) and citrus vinegar (CV) were classified as rest vinegars. Fruit vinegars were found to be rich in metabolites and antioxidant properties, as compared to grain vinegars. OV had the highest content of the quercetin derivatives and phenolic acids, and showed strongest antioxidant activity. Of the 28 metabolites identified, quercetin-3-O-rhamnoside-7-O-glucoside and quercetin-3-O-glucosyl-rutinoside were determined to be the main contributors to antioxidant activity in vinegars. The current study suggests that metabolite profiling by UHPLC–MS can be used to illuminate compounds associated with antioxidant properties as well as selection for vinegar type with the high content of bioactive metabolite profiles.