The use of response surface method to optimize the extraction of natural dye from winery waste in textile dyeing

Abstract

Grape pomace, which is a winery waste is studied and experimented to serve as a source of natural dyes that could be utilized in textile dyeing. The present study aims at developing and optimizing an extraction method of natural dye derived from grape pomace in order to dye silk fabrics. The water-acidified ethanol (20–40%) mixture is used mainly for the extraction of anthocyanins at different durations and at different temperatures (20–40 °C) from grape pomace. Effects of these independent variables (percentage of acidified ethanol, temperature, and duration of extraction) and their interactions during the extraction are determined by response surface methodology based on three-level three-factorial Box–Behnken design. Optimized values of percentage of acidified ethanol, temperature, and the duration of extraction for the optimization of monomeric anthocyanins concentration (75 mg L⁻¹) are found as 40%, 32,7 °C, and 38 h, respectively. The extract has been used for silk fabrics dyeing. The effects of some parameters (temperature, pH, and salt addition) on dyeing silk fabrics have been studied and optimized. The use of tannic acid as a natural mordant to improve the dye fastness proprieties has been investigated.

Keywords:

• Grape pomace
• anthocyanin
• natural dye
• dyeing
• silk fabrics
• Box–Behnken design