Screening of characteristic umami substances in preserved egg yolk based on the electronic tongue and UHPLC-MS/MS

Abstract In this study, the electronic tongue, ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and multivariate statistical methods were used to explore the characteristic taste of preserved egg yolk. The results of the electronic tongue showed that the prominent characteristic taste of preserved egg yolk was umami, and there existed significant differences in metabolites between preserved egg yolk and fresh raw yolk according to UHPLC-MS/MS results. Combined with principal component analysis (PCA), orthogonal partial least squares-discriminate analysis (OPLS-DA) and partial least square analysis (PLS), the umami flavor profile of preserved egg yolk was obtained. Glutamic acid (Glu), aspartic acid (Asp), nucleotides, succinic acid, betaine, glutamyl peptides and their derivatives were considered to be the important components of umami substances in preserved egg yolk. Other substances such as carnosine, glutamine and lipids may promote its umami taste retention. Interestingly, it was also found that the change of lipids had a certain effect on the umami taste of preserved egg yolk. Consequently, we explored the characteristic flavor of preserved egg yolk and provided metabolite information of its related umami-producing substances.