Integrating untargeted metabolites and targeted analysis for discrimination of kiwifruits from different cultivars

Abstract

To investigate the differences among kiwifruits from six different cultivars (Actinidia chinensis, Actinidia delicosa and Actinidia arguta), UPLC-QTOF-MS and UPLC-ESI-MS/MS coupled to multivariate statistical analysis were applied to untargeted metabolites and targeted analysis of kiwifruit samples for the first time. In untargeted analysis, the metabolome of kiwifruits was exhibited by principal component analysis (PCA), a total of 44 up-regulated feature compounds were screened based on the orthogonal partial least squares-discriminant analysis (OPLS-DA) and identified as glycosyl compounds, hydrocinnamic acids and various flavonoids. Furthermore, the contents of 27 targeted procyanidins, flavonoids and hydrocinnamic acids were analyzed by a UPLC-ESI-MS/MS method. It was indicated that phenol glycosides were much higher in A. arguta, responsible for the aroma of kiwifruits, various quercetin glycosides were higher in A. arguta, and much higher flavan-3-ols and hydrocinnamic acids were rich in A. Chinensis cv. Hongyang (red) kiwifruits. In addition, the results of chemometric analysis showed the untargeted metabolites and targeted compounds were responsible for the classification on the kiwifruits, which can benefit the scientific understanding of chemical diversity for kiwifruits, and improve the investigation of new wild kiwifruit cultivars, especially red kiwifruit and A. arguta.