Polyphenol composition and antioxidant capacity in pulp and peel of apricot fruits of various varieties and maturity stages at harvest

摘要

Polyphenol composition and antioxidant capacities of peel and pulp tissues of six apricot varieties were determined. Variations in polyphenol and antioxidant capacity based on variety (early-maturing varieties and late-maturing varieties) and harvest maturity (green mature and full mature) were assessed. The results of principal component analysis revealed that (+)-catechin made the most important contributions to the antioxidant capacities of the pulp. As the (+)-catechin content in 'Dajie' apricot decreased by 36.8% from green mature to full mature, the antioxidant capacities determined by ABTS free radical scavenging assay, DPPH free radical scavenging assay and cupric ion reducing antioxidant capacity assay decreased by 50.0%, 45.2% and 45.8%, respectively. Levels of phenolic compounds in the apricot peels were approximately 2-4 times higher than those of the pulps. Quercetin-3-rutinoside may be substantially responsible for the antioxidant capacities of the peels. The late-maturing varieties tended to have higher levels of phenolic compounds and higher antioxidant capacities than the early-maturing varieties. The antioxidant capacities in green mature apricots were much higher than those of full mature apricots.