Polyphenol traits, antimicrobial property and consumer preference of ‘Italian Red Passion’ apple genotypes and cultivar ‘Annurca’

Apple polyphenols may promote health and reduce the risk of chronic disease by various mechanisms, including antioxidant, antiproliferative, and cell signaling effects. Furthermore, these compounds are active as repressors of antimicrobial activity. Apple plants from M3, M4 and M5 genotypes, belonging to the red-flesh group 'Italian Red Passion' (IRP), generated from open pollination, show red coloration of flesh, leaf and flower. This phenotype is due to a mutation in the promoter region of MYB10, a gene encoding a transcription factor that up-regulates genes coding enzymes involved in apple anthocyanins production. Comparative analysis of HPLC data confirmed that extracts from fruit and leaf samples of IRP lines contained a larger array of compounds compared to samples of the 'Annurca' apple cultivar. These compounds belong to different chemical groups, such as anthocyanins, hydroxycinnamic acids, flavonols, procyanidins and dihydrochalcones. Fruit and leaf extracts of IRP exhibited antimicrobial activity against Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The extracts' antimicrobial activities were found to be dependent on the extraction solvent used. In addition, sensorial analysis highlights the good global preference of IRP red-flesh apples, which ranks similar to commercial cultivars.