Effect of Different Drying Methods on Physicochemical Properties and Antioxidant Activities of Postharvest Okra Pods

Abstract

Effects of hot-air drying (HD) and microwave drying (MD) methods on the physicochemical properties and antioxidant activities of postharvest okra was investigated. The weight loss rate and the contents of vitamin C, chlorophyll a, protein, soluble pectin as well as antioxidant activities of okra pods were determined. The results showed that HD and MD methods had significant influences on the physicochemical properties and antioxidant activities. The weight loss rate of okra treated by HD method was 87.45%, and it was 75.04% treated by MD. Both of them presented lower contents of chlorophyll a with a ranges of 0.33 ± 0.01 mg/g and 0.23 ± 0.02 mg/g. The protein contents of the HD was 16.38 ± 0.49%, and 9.16 ± 0.11% for MD method. The soluble pectin contents were 29.1 ± 0.76 mg/g and 28.26 ± 0.57 mg/g for HD and MD methods, respectively. It indicated that the nutrients in okra pods are susceptible to thermal processing, and the high temperature will significantly reduce the nutritional value. The specific conditions for different thermal processes should be studied and optimization.