Investigation the spatial distribution of polyphenols and metabolomic profiling of apple

Abstract

Aim: In this study, Polyphenol and chemical profiles in core, pulp, and peel of 7 apple varieties [Fuji (FS), Qinguan (QG), Qingping (QP), Jinshuai (JS), Gala (GL), Changmiou (CMO), and Huahong (HH)] were comparatively studied to distinguish the different metabolism biomarkers in the three parts of apple fruit. Methods: This study investigated the distribution of 15 polyphenolic compounds using a combination of multivariate analysis and ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). Results: chlorogenic acid, catechin, epicatechin, phloretin were the most abundant components. While phloretin was the dominant component in core, chlorogenic acid was the main phenolic compound in pulp, and quercetin was mainly found in apple peel. The multivariate analysis showed that the chemical profile of peel was significantly distinct from that of apple pulp and core, whereas apple pulp and core overlapped with each other. The difference attributed to the compounds that were predicted from ultra-high performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS), which were remarkably different (P < 0.05) and belong to polyphenol. Conclusions: It indicates that the potential superior biomarker of polyphenols is to differentiate the products from apple core, pulp, and peel respectively. This research provided an insight on the polyphenolic profile of core, pulp, and peel of apple fruits.