AKTIVITAS ANTIOKSIDAN EKSTRAK ETANOL 30% KULIT BUAH MANGGIS (Garcinia mangostana L.) SEBELUM DAN SESUDAH PROSES PENGERINGAN DALAM OVEN 60OC

Abstract

Ethanol extracts of mangosteen fruit rind contain high antioxidant activity that is heat labile. Drying of ethanol extracts containing antioxidant activity ideally is carried out at low temperatures using a vacuum freeze dryer. In the absence of a vacuum freeze dryer other methods must be used, such as oven drying but at temperatures with minimal loss of the antioxidant activity. To evaluate the effects of the drying process, the antioxidant activities of mangosteen fruit rind 30% ethanol extracts before and after oven drying at 60oC was compared to each other. Dried powdered mangosteen fruit rind was incubated in 30% ethanol for 8 days at 40ºC and 100 rpm in a shaking incubator. After incubation, the mixture was filtered to separate the ethanol extract from the remaining solids. The ethanol solvent from the filtered extract was evaporated by rotary vacuum evaporation at 50oC, and the semi-dried residue was further oven dried at 60oC to constant weight. The antioxidant activity of the semi-dried extract residue and oven dried extract was analyzed using the 2,2 diphenyl-1-picrylhydrazyl (DPPH) method. The results showed that the IC50 value of the antioxidant activity from mangosteen fruit rind 30% ethanol extract before the drying process was (42.78±1.54) μg/mL, and after the drying process was (21.30±2.29) μg/mL. Unpaired student t analysis to compare the average IC50 values of the 30% extracts before and after drying showed that there was a significant increase (p<0,05) in the antioxidant activity after the 60oC oven drying process.