Phytochemical Profile of Selected Processing Apple Genotypes

The phenolic composition in the flesh and peel of 19 advanced apple breeding lines and cultivars to be released for fresh market and processing was determined by high performance liquid chromatography (HPLC). Total phenolic content (TPC) by the Folin-Ciocalteu (FC) method and total antioxidant capacity using ferric reducing/antioxidant power (FRAP) were also determined. HPLC analysis revealed the presence of several sub-classes of phenolics: proanthocyanidins, hydroxycinnamate acids, flavan-3-ols, flavonols, and dihydrochalcones. The profile of phenolic compounds varied among the 19 tested genotypes and the peel showed higher concentrations than the flesh. Proanthocyanidins were the most predominant sub-class in both flesh and peel and contributed 49.7% and 48.7% of the total phenolic index (TPI), respectively. Flavonols were not found in the flesh, except quercetin 3-rhamnoside, which was detected in almost all tested genotypes. In contrast to all other genotypes, flavan-3-ols were not detectable in the flesh of 'Eden'. Cyanidin glycosides were exclusively found in the peel, except for 'Floribunda Rosea', which contains in both peel and flesh. 'Floribunda Rosea' was found to possess the highest concentrations of polyphenols and TAC, whereas 'Eden' had the lowest. The significant variation in total antioxidant capacity (TAC), TPI and TPC indicates the potential use of some new cultivars and advanced lines as parents in breeding programs targeted towards developing superior apple genotypes with higher levels of antioxidants.