Spectrophotometric studies of natural pigment in beta vulgaris and curcuma longa and application on silk fabric as a natural dye / Shabinah Filza Mohd Sharib

The natural pigment in Beta vulgaris and Curcuma longa were observed in spectrophotometric studies. These natural pigments were extracted using a conventional method which is boiling with distilled water at four different temperature (40˚C, 60˚C, 80˚C and 100˚C). The crude extract was then analyzed by UV-VIS Spectrometer over the range of 400nm to 800nm. The maximum absorbance of Beta vulgaris crude extract was observed at 60˚C with λmax of 487.72nm and 534.04nm. While the maximum absorbance of Curcuma longa crude extract was observed at 100˚C with λmax of 422nm. The studies show that the natural pigment in Beta vulgaris and Curcuma longa tend to degrade when exposed to sunlight and high temperature. Maximum percentage degradation of the natural pigment in Beta vulgaris and Curcuma longa are observed when exposed to sunlight and light respectively. The best condition for both natural pigments is in the dark room that give lowest percentage degradation than other conditions. Silk fabric dyed with natural pigment in absent and presences of mordant were also studied. The initial colour of the silk fabric changes when dyed with natural pigment and mordant. The three mordant used were copper (II)sulphate (CuSO4.5H2O), stannous chloride (SnCl2.2H2O) and potassiumdichromate (K2Cr2O7) and it is mordanted with the natural pigment using pre-mordanting method to give variation of colour.