Effects of UV-B irradiation on phenolic compound accumulation and antioxidant activity in ‘Jonathan’ apple influenced by bagging, temperature and maturation

Author: Davood Bakhshi ¹ and Osamu Arakawa ^*

Received 18 August 2005, accepted 22 October 2005.

Abstract

The effects of UV-B and white light irradiation on phenolic accumulation in apple (Malus domestica Borkh cv. Jonathan) was investigated in the skin of bagged and non-bagged fruits harvested at mature and ripe stages, 132 and 156 days after full bloom (DAFB) and irradiated at 10, 17, 24 and 30°C for 96 hours. Mature and ripe fruits synthesized the most cyanidin 3-galactoside, quercetin 3-galactoside and epicatechin at 17°C and 24°C, respectively. The total oxyradical scavenging capacity (TOSC) showed a positive relationship with flavonoid content and antioxidant capacity of mature and ripe fruits was also at its highest at 17°C and 24°C, respectively. There was a strong relationship between total phenolic content and antioxidant activity; and cyanidin 3-galactoside, quercetin 3-galactoside and epicatechin were the strongest antioxidants among skin phenolics.