keywords: Cashew, Anacardium occidentale, natural dyes, anthocyanins fruit juice
Cashew (Anacardium occidentale) fruits were collected from Girei Local Government Area of Adamawa State in Nigeria and dye extracted using ethanol as solvent. Ethanol was removed using rotary evaporator and dye extract was characterized by UV-Visible, FTIR, GC and MS spectrophotometers. The UV-Visible spectra indicated peaks at 195, 218, 263, 298, 358, 379 and 658 nm. FTIR spectrum indicated band at 2930 and 2860 cm-1 corresponded to C-H stretching vibration, 1711, 1602 and 1514 cm-1, corresponded to C=O stretch of amide, C=C of aromatic hydrocarbon and N-H, respectively. These chromophoric groups may be responsible for the formation of red-orange-yellow colour of the dye extract. Compounds such as N.N-Dimethyl-o-(1-methyl-butyl-)hydroxylamine and 2,4,7,14-Tetramethyl-4-vinyl-tricyclo[5,4,3,o(1.8)]tetradecan-6-ol and N,N’-Bis(Carbobenzyloxy)-lysinemethyl(ester) were obtained by GC and MS spectra. It was then concluded that the dye extract could be a mixture of compounds belonging to the family of anthocyanins. Therefore, interaction between these coloured substances with cellulose could lead to the formation of strong bonds which may be difficult to break by common surfactants thereby creating a near permanent stain on the material.