Content of bioactive compounds and antioxidant capacity in skin tissues of pear

The amounts of bioactive compounds (phenolic compounds, triterpenoids and carotenoids) and antioxidant activities of peels from 10 different pear cultivars were studied. Polyphenols, triterpenoids and carotenoids were identified and quantified by liquid chromatography photodiode array quadrupole time-of-flight mass spectrometry (LC-PDA-QTOF/MS), while antioxidant capacities were evaluated in vitro using scavenging assay of 1,1-diphenyl-2-picrylhydrazyl radical and ferric reducing power. A total of 44 polyphenolic compounds were identified: 18 hydroxycinnamic acids, 13 flavan-3-ols, 10 flavonols, 1 flavone, 1 hydroquinone and 1 anthocyanin. Three triterpenoids (betulinic, oleanolic and ursolic acid), 4 carotenoids and 7 chlorophylls were identified. It was found that the cultivars had different phenolic, triterpenoid and chromoplast pigment concentrations. In addition, a positive correlation between antioxidant capacity and content of bioactive compounds was found.