Discrimination and investigation of inhibitory patterns of flavonoids and phenolic acids on heterocyclic amine formation in chemical model systems by UPLC-MS profiling and chemometrics

To discriminate and investigate the inhibitory patterns of different categories of ingredients from natural origin such as spice is necessary to elucidate the inhibitory mechanism of them on heterocyclic amines (HAs) formation. In this work, the inhibitory patterns of flavonoids (naringenin, quercetin, luteolin and rutin) and phenolic acids (chlorogenic acid, ferulic acid, p -coumaric acid and protocatechuic acid) on HAs in a mixed chemical model system were discriminated and examined by UPLC-MS profiling combined with principal component analysis (PCA) method with the interpretation of scores, loadings, contribution and biplots. Seventeen HAs from seven categories were profiled by UPLC-MS; furthermore, the precision for most of these HAs upon three repeated samples was between 4.2 and 13.9 %, and their recoveries were between 58.4 and 97.1 %. Seven HAs: norharman, harman, DMIP, PhIP, IQx, MeIQx and 4,8-DiMeIQx were detected and quantified in all of the samples without and with flavonoids (phenolic acids), thus employed in the subsequent multivariate analysis. The PCA results show that the inhibitory patterns of the two groups are different; moreover, flavonoids have inhibitory potential to norharman, PhIP, 4,8-DiMeIQx, while phenolic acids have possible capability of inhibiting DMIP formation. The results have demonstrated that the proposed UPLC-MS profiling method may be a useful tool for differentiating and exploring inhibitory patterns of different categories of ingredients from natural origin on HA formation.