Antioxidant capacity changes of bird chili (Capsicum frutescens Linn.) during hot air drying.

Abstract

The antioxidant capacity of bird chili (Capsicum frutescens Linn.) during hot air drying at 70, 100 and 121°C was analyzed by three different methods: ferric-reducing, antioxidant power (FRAP) assay; improved, ABTS, radical cation decolorization assay; and DPPH, free radical scavenging activity, together with the analysis of total phenolic content and browning pigment formation. It was found that total phenolic content might decrease at the beginning of the drying process, but that it would increase when the browning pigments were developed. Phenolic compounds of fresh, red bird chili were less heat stable than the ones of fresh, green bird chili. In addition, the antioxidant capacity of dried bird chili was dependent on the degree of browning and the drying temperature. All the antioxidant capacities of the dried products were higher than for the fresh ones, except after drying at 70°C, when the reducing power, FRAP value, of dried green and red chili was lower than the fresh one, and the values of the free radical scavenging activities, ABTS and DPPH of dried red bird chili did not change.