Effects of modified atmosphere package and 1-MCP treatment on the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity of okra (Abelmoschus esculentus) during storage

Okra (Abelmoschus esculentus) is widely spread in tropical and subtropical areas. It has been favoured as a food for the health-conscious. Okra pods possess significant antioxidant activity and phenolics as well as flavonoids are active constituents. Fresh okra deteriorates quickly during storage due to tenderness and a high respiration rate. Modified atmosphere package and 1-MCP treatment were developed to extend the storage limit successfully. However, the antioxidant activity of okra during storage was not clarified. The objective of the study was to determine the total flavonoid and phenolic contents as well as total antioxidant activity of okra during storage by using modified atmosphere package and 1-MCP treatment. Fresh okra pods were sealed into 25x35-cm bags comprised of 0.03 and 0.1-mm-thick low density polyester (LDPE) film or 0.01-mm-thick high density polyester (HDPE) film and stored at 12 degrees C. Okra pods were treated by 1-MCP (0.5, 10, and 20 mg L-1) for 16 h at 6 degrees C before storage. Total flavonoid and phenolic contents as well as DPPH radical scavenging activity were checked every week during storage. Results showed that okra pods packaged in low density polyester bags of 0.03 mm thickness showed the highest total flavonoid and phenolic contents as well as DPPH radical scavenging activity during storage at 12 degrees C. 1-MCP pretreatment minimized the decrease of total flavonoid and phenolic contents as well as DPPH radical scavenging activity at 12 degrees C. Good correlations were found between DPPH radical scavenging activity and contents of total flavonoid and phenolic in okra pods stored at 12 degrees C for 4 weeks.