Effect of Blanching Treatments on Antioxidant Activity of Frozen Green Capsicum (Capsicum annuum L. var bell pepper) using Radical Scavenging Activity (DPPH) Assay

摘要

Blanching treatments are needed to deactivate enzymes in frozen vegetables. Antioxidant activity using DPPH radical scavenging activity assay were evaluated in steaming, boiling water, and microwave blanching at different temperature, time and microwave power level on frozen green capsicum. Green capsicum was chosen for frozen treatment compared to other capsicum with different maturity index because of the firm texture. The objective of this study was to compare the antioxidant activity of frozen green capsicum between conventional and Oxi Count Kit? assay for DPPH radical scavenging activity. Results showed frozen green capsicum blanched using microwave at high level/90 seconds (sample J) contained higher level of DPPH in both conventional method and Oxi Count Kit? compared to other treatments. However, there were no significant differences between sample J and fresh sample (sample A). Overall, the sequences from highest to lowest in blanching treatments for both DPPH conventional method, and DPPH Oxi Count Kit? were J (microwave high level/90 seconds)> A (Fresh)> H (Microwave Medium Level/120 seconds)> D (Boiling Water 80°C/150 seconds)> K (Microwave High Level/120 seconds)> I (Microwave Medium Level/150 seconds)> F (Microwave Low Level/150 seconds)> B (Steam 100°C/150 seconds)> E (Boiling Water 100°C/120 seconds)> G (Microwave Low Level /180 seconds)> C (Steam 100°C/180 seconds). Almost all frozen green capsicum samples showed no significant differences for comparison between test using DPPH conventional method and Oxi Count Kit?. Frozen storage for 0, and 3~(rd) months showed no significant differences which indicate no changes on antioxidant activity during frozen storage at -18°C.