Quantification of Phenolic Compounds in Peel and Pulp of 'Zonouz' Apple Cultivar from Iran

Abstract

Composition of phenolic compounds in peel and pulp of 'Zonouz' apple cultivar was studied during three fruit growth stages (early, middle and harvesting stages) using HPLC. Based on the obtained results, pulp contained the highest amounts for total phenolic and flavonoid compounds as well as total phenolic acids content during early growth stage. In peel, total phenolic and flavonoids were decreased till mid-season and then were raised at commercial harvest time. Total phenolic acids concentration attained declining trend till end-season. Chlorogenic acid was the major peel phenolic acid constituent in all three stages. Peel flavanols had their highest amounts during mid-season with a variation pattern: early season < mid season < harvest time. Pulp flavonols achieved their maximum amount during early growth stage. Cyaniding-3- galactoside (63%) and pholridzin dehydrate (20%) were the main flavonoids of early growth stage in peel. Rutin hydrate (56%) dominated in pulp during early growth stage. During the second measurement i.e. mid-season, catechin was the major flavonoid component in both peel and pulp. Cyaniding-3- galactoside (67%) was the most abundant flavonoid compound in peel at harvest time.