Antioxidizing Enzyme Activities in Chilling-sensitive and Chilling-tolerant Pepper Fruit as Affected by Stage of Ripeness and Storage Temperature

Abstract

To study ripening-related chilling injury in pepper (Capsicum annuum L.), chilling-tolerant ‘Buchon’ and chilling-sensitive ‘Nockgwang’ fruit were harvested at mature green (MG), breaker (BR), and red-ripe (RR) stages and stored at 1, 5, and 10 °C for 21 d. ‘Buchon’ did not show surface pitting (SP) regardless of ripeness stage and storage temperature, whereas ‘Nockgwang’ at MG and BR exhibited SP at 1 and 5 °C. After 14 days of storage at 1 °C, chilling-sensitive ‘Nockgwang’ did not show SP when fruit were at the RR stage. Compared with ‘Buchon’, ‘Nockgwang’ at MG and BR had more electrolyte leakage increase during storage at 1 and 5 °C. ‘Buchon’ at all ripeness stages showed significantly higher ethylene production during storage regardless of storage temperatures. Contents of β-carotene and lycopene increased in both cultivars as ripening progressed. The contents of β-carotene and lycopene were similar between the two cultivars regardless of storage temperatures and ripeness stages. Susceptibility of pepper fruit to chilling appeared to be related to superoxide dismutase (SOD) and catalase (CAT). Activities of SOD and CAT were much higher in ‘Buchon’ than ‘Nockgwang’, more apparently at MG and BR. The results suggest that chilling-tolerant ‘Buchon’ and fruit at RR could have been equipped with a more efficient antioxidizing system, even if it was not clear whether oxidative stress is a cause or an effect of the CI in pepper.