Abstract:
The aim of this research was to investigate the optimum condition for antioxidants extraction fromtamarind seed coat (Tamarindus indica L.). Extractions with supercritical carbon dioxide as well aswith solvent extraction were carried out. Supercritical carbon dioxide extractions were performedusing an ISCO Model SFXTM 3560 laboratory extractor. The effects of ethanol as co-solvent,temperature range 35-80 OC, pressure range 10-30 MPa and the ratio of ethanol to carbon dioxiderange 5-10 percent volume by volume were investigated. Solvent extractions were also studied. Theeffects of method of extraction, temperature and type of solvent were investigated.It was found that antioxidative component prepared from the seed coat was (-)-Epicatechin. Theuse of a 10 percent of ethanol co-solvent resulted in a much higher yield of (-)-Epicatechin, (12.75mg/100 g dry weight of seed coat), under the best conditions which were found to be 40 OC and 10MPa. The results showed that ethanol extraction at ambient temperature has a higher productivitythan supercritical carbon dioxide extraction, yields of (-)-Epicatechin was 120.79 mg/ 100 g dryweight of seed coat. The extracts prepared fiom supercritical carbon dioxide extraction has purityhigher than ethanol extraction. However the ethanol extraction has a higher yield of (-)-Epicatechin about 10 fold. In addition the antioxidants extracted from tamarind seed coat usingsolvent extraction with ethanol was found to be the most active in terms of peroxide value.