Developmental variation of phenolic compounds in fruit tissue of two apple cultivars.

BACKGROUND Qualitative and quantitative analyses of 'Zonouz' and 'Gala' apples phenolic compounds were accomplished by HPLC. MATERIAL AND METHODS Samples for phenolics study were taken at three different growing stages [1 - fruit early growing stage 2 - mid-stage of fruit development (80 days after full bloom) 3 - during commercial harvest time]. RESULTS The results showed qualitative differences between two apple cultivars regarding phenolic compounds. The highest amounts of total phenols, flavonoids, flavonols and phenolic acids content in both cultivars were recorded during the fruit early growing stage. The high phenolic acids content was due to increasing in chlorogenic acid content in fruits during early growing stage. The highest amount for flavanol content was recorded in 'Zonouz' peel at the harvest time. Descending pattern was recorded for phloridzin dihydrate content during the season. 'Gala' peel had the greatest amounts for cyanidin-3-galactoside at harvest time. Increasing in total flavonoid content was due to the great amounts of cyanidine-3-galactoside and epicatechin (in 'Gala' peel), rutin hydrate (in 'Zonouz' pulp) at fruit early growing stage, catechin (in 'Zonouz' peel) during mid-stage of fruit development and cyanidin-3-galactoside and quercetin-3-D-galactoside (in 'Gala' peel) at the harvest time in both apple cultivars. CONCLUSIONS There were meaningful quantitative differences between two cultivars, and 'Gala' was richer in phenolics than 'Zonouz'.