2018 ASHS Annual Conference

Apple fruit (Malus domestica) is one of the most consumed fruit in the world due to its flavor quality and nutritional value. The production of apples plays an important role in economic development in the world. Apple fruit contain significant amounts of phytochemicals including phenolic compounds, anthocyanins and other compounds which are recognized as important bioactive compounds contributing to human health and well-being. Many of these phenolic compounds are strong antioxidants, including simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids such as quercetin, epi-catechin, catechin, phloridzin, chlorogenic acid, quercetrin and procyanidins. Phenolic compounds in apples are influenced by many pre- and postharvest factors. To determine the diversity of phenolic compounds in apple cultivars, we evaluated 88 and 144 apple cultivars grown in Nova Scotia in 2015 and 2016, respectively. Fruit were harvested at commercial harvest maturity and stored at 3.0 °C for one month prior to phenolic compound analysis. High performance liquid chromatography (HPLC) with photo diode array and fluorescence detection was employed to determine phenolic and anthocyanin composition of apple tissues. Five major polyphenolic groups composed of total phenolics, total hydroxycinnamic acid derivatives, total flavonols, total fluorescence and total anthocyanins as well as 14 individual compounds were identified and quantified. Significant variation of phenolic compounds and anthocyanin among apple cultivars was found. For some compounds, concentrations differed by more than 6 times among the cultivars in the two populations indicating that a strong genetic regulation may control phenolic metabolism in apples. Our study also revealed correlations among the different classes of phenolics with diseases resistance as well as the development of physiological disorder. These research findings will lay the foundation for future genetic improvement of the phenolic composition of apples.