Flavonoid and chlorogenic acid concentrations in skin of 'Jonagold' and 'Elstar' apples during and after regular and ultra low oxygen storage

Apples are important dietary sources of potentially healthy phenolics. In t hree successive seasons, the changes in concentrations of flavonoids and ch lorogenic acid in the skin of two apple cultivars 'Jonagold' and 'Elstar' d uring and after regular (RS) and ultra low oxygen storage (ULO) at 1 degree s C, were quantified by reversed-phase high performance liquid chromatograp hy (RP-HPLC) with UV-VIS detector. There were no significant differences in the concentrations of flavonoids and chlorogenic acid between fruits store d under ULO and RS conditions. During storage of both 'Jonagold' (3, 6 and 8 months) and of 'Elstar' (2, 4 and 6 months), and during 1 or 2 weeks shel f life, the concentrations of cyanidin 3-galactoside and quercetin glycosid es were relatively constant, while the concentrations of catechins, phlorid zin and chlorogenic acid showed only minor changes. Exposing 'Jonagold' and 'Elstar apples' to white light during shelf life following storage increas ed the concentration of cyanidin 3-galactoside but not any of the other fla vonoid classes. An explanation for this might be that the synthesis of diff erent flavonoid classes may have different spectral sensitivity characteris tics. It is concluded that flavonoids present in apples are stable and poss ibly not subject to net metabolic turnover during storage and shelf life. ( C) 2000 Elsevier Science B.V. All rights reserved.