Identification of Polyphenolic and Flavonoid Compounds in  Zonouz and  Gala Apple Fruits by Means of High-Performance Liquid Chromatography

Qualitative and quantitative analyses of ‘Zonouz’ and ‘Gala’ apples polyphenolic compounds were carried out by HPLC during the commercial harvest time. The results showed qualitative differences between the two apple cultivars regarding polyphenolic compounds. In general, ‘Gala’ had higher polyphenolic compounds compared to ‘Zonouz’. The highest polyphenolics content was recorded in the Gala's peel and seed. The predominant flavonoids in the Gala's peel were quercetin-3-D-galactoside and cyanidin-3-galactoside with 45.7% and 42.3% of the total identified components, respectively. Phloridzin dihydrate (86.3% of the total flavonoid compounds) contained the principal flavonoid compound in the Gala's seed. Cyanidin-3-galactoside and (-)-epicatechin were the main flavonoid compounds in the Zonouz's peel with 65.4 and 26.1% of the total flavonoids. Phloridzin dihydrate (82.6% of the total flavonoids) was the major flavonoid compound in the Zonouz's seeds. The Zonouz's Peel and pulp had higher flavonoid and phenolic acids content compared to Gala. Chlorogenic acid (1mg/g DW) and (-)-epicatechin (0.5mg/g DW) were the highest phenolic acid and flavonoid components in the Zonouz's peel and pulp, respectively. Rutin hydrate was another major flavonoid constituent of Zonouz's pulp with 5.8% of the total identified flavonoids. This compound was absent in the Gala's pulp. Caffeic acid content in the Zonouz's pulp (0.3 mg/g DW) was considerably higher than Gala (0.08 mg/g DW).