Untargeted metabolomics analysis reveals the biochemical variations of polyphenols in a diverse apple population

Apples are an important dietary source of polyphenols as antioxidants that contribute to human health. Based on total phenolic content and total antioxidant capacity data gathered from a large apple biodiversity collection, we applied untargeted metabolomics analyses to further understand the phenolic composition in select accessions with very low and very high phenolic contents, as well as in commercial cultivars. The liquid chromatography-mass spectrometry (LC-MS) analysis provided both qualitative and quantitative information, with 2,946 features detected using the positive mode of electrospray ionization. We found significant variation in total polyphenols, and strong correlations between total phenolic content and total antioxidant capacity. Polyphenolic compounds significantly associated with each group of apples were quantified, and new features were putatively identified. This study provides new knowledge regarding the specific polyphenols that contribute to the variation in total phenolic content and antioxidant capacity among apples, and new insights into the biochemical regulations of polyphenol biosynthesis and composition.