title: Comparison of antioxidant capacity and phenolic composition of peel and flesh of some apple varieties.
abstract: BACKGROUND
  Apples contain a large concentration of phenolic compounds, dependent on factors such as cultivar, harvest, storage conditions, and processing. This study aims to identify the essential phenolic compounds present in various apple varieties, to measure their total antioxidant capacity (TAC) with the CUPRAC (cupric ion reducing antioxidant capacity) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate)) methods, and to correlate their TAC values with HPLC findings.
  
  
  RESULTS
  The order of TAC (mmol Trolox g(-1) fresh weight) of apple peels determined with the CUPRAC method was: Granny Smith > Amasya > Sky Spur > Ervin Spur > King Luscious ≥ Arap Kizi ≥ Lutz Golden. The theoretically calculated TAC values of HPLC-quantified compounds, with the aid of the combined HPLC-CUPRAC method, accounted for 18.4-33.5% of the experimentally observed CUPRAC capacity of peel extracts and 19.5-56.3% of flesh extracts, depending on apple variety.
  
  
  CONCLUSIONS
  In synthetic samples of apple antioxidants, the CUPRAC-TAC values of constituents, identified and analyzed by HPLC, proved to be additive, enabling measurement of the cooperative action of antioxidants using the proposed methodology. Apple peel showed higher contents of phenolics and therefore higher TAC than apple flesh, confirming the health benefit of the consumption of apples together with peel.
authors.affiliation: Department of Chemistry, Faculty of Arts and Science B. Çekmece, Fatih University, 34500 Istanbul, Turkey.
authors.forename: Seyda
authors.initials: S
authors.lastname: Karaman
authors.forename: Esma
authors.initials: E
authors.lastname: Tütem
authors.forename: Kevser Sözgen
authors.initials: KS
authors.lastname: Başkan
authors.forename: Reşat
authors.initials: R
authors.lastname: Apak
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D004032:Diet; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D027845:Malus / Q000737:chemistry* / Q000145:classification; D010636:Phenols / Q000032:analysis / Q000494:pharmacology*; D013045:Species Specificity
chemical_list: D000975:Antioxidants; D010636:Phenols