Utilization of Indigofera Leaves as Natural Dyes for Silk Fabrics

Abstract

Indigo is a natural blue dye produced from the leaves of the Indigofera plant, which is environmentally friendly and non-carcinogenic. This study aimed to determine the reduction potential value of molasses and brown sugar as reducing agents, to examine the effect of the hydrochloric acid concentrations and aeration time on the amount of indigo, and to test the fastness of rubbing against solar heat, dry, wet and acid on silk fabrics that were dyed by indigo with various fixators. To extract the indigo dye, the Indian glycosides contained in Indigofera leaves were hydrolyzed to indoxyl and glucose using hydrochloric acid. Indoxyl was then oxidized to indigo using molasses as a polysaccharide compound. The results showed that the concentration of 0.01 M hydrochloric acid produced the highest indigo content of 26.83 ppm, and the best aeration time was 4 hours to produce indigo with a concentration of 22.32 ppm. The effect of the fixator types produced different colors. The fixator of ferrous sulfate produced a dark blue-green color, limestone produced a light blue color, while alum produced a bright blue color. The fastness test showed the same result as the gray sale value of 4-5 meaning that there was a slight fading.