Studies on the Dyeing Properties of Cotton and Antimicrobial Activity of Natural Colourant Extracted from Beta vulgaris (Beetroot)

Abstract

Natural colourant was extracted from beetroot (Beta vulgaris) with Soxhlet apparatus using water, ethanol, ethyl acetate and aqueous methanol (50%). Methanol (50%) gave a higher yield of dyestuff than the other solvent. The stability of the dye on pH and temperature was best found to be 4.5 and 50ºC respectively. The purification and separation of the extract was done using TLC and micro column, the better Rf values were found to be 0.47, 0.36 and 0.24 when methanol and hexane (4:1) were used as the solvent. FTIR was used to characterize the extract and it showed that active component in the dye was present. Analysis of the dye was done with UV/visible spectrophotometry at a 538 λmax. The cotton fabrics were dyed with crude extract and a mordant (ferrous sulphate and alum) under conventional dyeing techniques; pre-mordanting and meta-mordanting, adopting a well-known vat dyeing method. The dyed fabric possessed very good fastness to light, rub and press but fair wash fastness. Ferrous sulpate as a mordant gave a better % exhaustion on dyed cotton and the dyeing was best achieved with pre-mordanting techniques. The antimicrobial activity test showed that, the extract was active against Staphylococcus aureus, Escherichia coli, and Aspergillus niger but non-active against Candida albican.