Comparison of phenolic compounds’ content and antioxidant activity between some native Iranian apples and standard cultivar 'gala'

To determine the phenolic content and antioxidant activity in some native Iranian apple cultivars, some five cultivars namely: 'Bekran', 'Golab-e Kermanshah', 'Golab-e Kohanz' 'Golab-e Sheikhi' and 'Atlasi' were selected and compared with the standard cultivar 'Gala'. The profiles related to four phenolic compounds (chlorogenic acid, quercetin-3-galactoside, catechin, and phloridzin) were determined through HPLC for flesh and flesh+peel of the studied cultivars. Total Phenolic Content (TPC) through Folin-ciocalteu, and antioxidant activity applying DPPH radical (IC50) were also evaluated for flesh vs. flesh+peel for each cultivar. The results of HPLC analysis revealed that catechin constituted the main phenolic compound of flesh and as well the flesh+peel in all the studied cultivars. The highest catechin concentrations in flesh+peel and in flesh were detected in 'Golab-e Kermanshah' (4,064.37 ug g-1FW) and 'Bekran' (2,315.92 ug g-1FW), recpectively. The second high concentration phenolic compound was quercetin-3 galactoside, with 'Atlasi' containing the highest content (833.96 ug g-1FW). A high level of chlorogenic acid was detected in 'Golab-e Sheikhi' (276.106 ug. g-1FW). The highest level of Total Phenolic Index (TPI) was observed in 'Golab-e Kermanshah' (4392.81ug g-1FW). The highest TPCs were detected in 'Golab-e Kermanshah' and 'Atlasi'. Phenolic compounds were found as less abundant in the flesh than in the flesh+peel. The scavenging activity of DPPH radical (IC50) revealed a higher antioxidant effect in flesh+peel than in (only) flesh. It can be concluded that in comparison with 'Gala', native Iranian cultivars contained higher concentrations of phenolic compounds, making them appropriate for use in breeding and being reintroduced into the production cycle. Also, it was revealed that whole fruit (flesh+peel) provides phytochemicals in levels far greater than the amounts provided by the fruit’s (only) flesh.