예냉 처리 시간이 저온저장한 Basil의 항산화효소 활성변화에 미치는 영향

Effects of Duration of Precooling before Cold Storage on Antioxidant Enzyme Activities of Basil(Ocimum basilicum L.)

Basil is one of popular culinary herbs in the world, and recently production and consumption have been increased in Korea. Chilling injury by storage temperature during cold storage transportation is a major factor to decrease its marketable value as well as growers income. This study aimed to investigate the effects of pre-cooling treatments prior to cold storage on activities of antioxidant enzymes of basil (Ocimum basilicum L.). Harvested basil leaves were pre-cooled in a chamber controlled at 12℃ for 0, 4, 8, 12, 16 and 24 hours prior to storage at 4℃ for 12 hours. After completion of pre-cooling and cold storage treatments, the activities of APX (Ascorbate peroxidase), SOD (Superoxide dimutase), and CAT (Catalase peroxidase) were measured. When the harvested leaves were placed in a chamber controlled at 4℃ for 12 hours without application of pre-cooling at 12℃, the APX activity was decreased by 40 % (P < 0.05), about 112 μmol/min/mg protein, compared to the level measured immediately after the leaves were harvested, 186 μmol/min/mg protein. In contrast, the highest level of APX activity was observed in the leaves treated with 16 hour-precooling at 12℃, about 186 μmol/min/mg protein. The APX activity in the leaves under longer-term pre-cooling application, 24 hours, was lower than those of leaves under 16 hours, indicating that proper length of pre-cooling treatment should not be longer than 16 hours. However, the activities of both SOD and CAT were not significantly affected by the pre-cooling treatments. All the integrated data suggest that pre-cooling treatment prior to cold storage is necessary to avoid chilling injury, and the APX enzyme appears to be a better indicator for physiological response of basil leaves to chilling injury than SOD and CAT enzymes.