Pear (Pyrus L.) Genetic Resources from Northern Japan: Evaluation of Antioxidant Capacity

'Iwateyamanashi' (Pyrus ussuriensis var. aromatica) is one of the Pyrus species grown wild in Japan. They have been utilized traditionally as food and medicine, but are not used now. Therefore, it has been decreasing, so conservation and evaluation are urgently needed. Over 750 accessions including Iwateyamanashi were collected and maintained at Kobe University. Antioxidant capacity of accessions from the collection maintained to evaluate its functional characters were analysed. In 2010 and 2011, we measured total polyphenol content and DPPH radical scavenging activity at mature stage among 29 accessions. In 2013, we evaluated temporal total polyphenol content and DPPH radical scavenging activity among 3 accessions. Almost 'Iwateyamanashi' had much higher antioxidant capacity than Japanese pear cultivars (P. pyrifolia) and European pear cultivars (P. communis L.). Especially, accession 'i0868' contained much polyphenol (1.40 mg g(-1) FW of (-)-epicatechin equivalent) and showed high DPPH radical scavenging activity (19.76 mu mol g(-1) FW of ascorbic acid equivalent). It indicated about 23 times higher polyphenol content and about 33 times higher DPPH radical scavenging activity than 'Hosui'. The fruit used in this study was found to possess high antioxidant capacity in an early development stage, and then it reduced according to increasing of fruit weight at full maturity. 'Iwateyamanashi' with high antioxidant capacity might stimulate the new demands as breeding materials and health foods.