Extraction of natural dyes for textile dyeing from coloured plant wastes released from the food and beverage industry

Abstract

AbstractThe food and beverage industry releases considerable amounts of wastes which contain natural dyes. Such wastes could serve as a sources for the extraction of natural dyes for textile‐dyeing operations. The extraction of brilliant yellow and red colours from fruits and vegetables is of particular interest. Wastes, e.g. pressed berries, pressed grapes, distillation residues from strong liquor production, and wastes and peels from vegetable processing, have been extracted with boiling water and test dyeings on wool yarn were performed. Colour strength, shade and fastness properties of the dyeings have been tested. The extracts were applied as direct dyes and in the presence of iron(II) or alum mordants. The results prove the potential of such wastes as a source for natural dyestuff extraction. To obtain textile dyeings with acceptable fastness properties, however, rigorous selection of dyes and development of suited processes is required. A considerable number of red natural dyes need further research to optimise the low level of fastness to light. Copyright © 2005 Society of Chemical Industry