Comparative study of organic solvents and extraction conditions on colour and antioxidant capacity in red cabbage

Abstract

In industrially natural-dye production, there are many organic solvent with different efficiencies for extracting colour and antioxidants of red cabbage. The objective of this study was to investigate appropriate organic solvent and extract condition on colour and antioxidant activity. Two organic solvents were used for extraction: ethanol for hydrophilic antioxidants and hexane for lipophilic antioxidants. Experimental results showed that red cabbage extracted by ethanol was significantly higher in purple colour, anthocyanin content, total phenolic content, antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl radical assay (DPPH), and ferric reducing/antioxidant power assay (FRAP) than extraction by hexane due to anthocyanins being the main phenolic compound in extract. To find the appropriate concentration and extraction time, the results revealed that the red cabbage extracted by 70% ethanol for 18 h was suitable for extracting bioactive polar compounds, such as hydrophilic antioxidants.