Study on the extraction of purplish red pigment from Solanum nigrum with resins

Taking Solanum nigrum as raw material,the different resins to the Solanum nigrum purplish red pigment adsorption rate and the desorption effect,and the elution effect of different eluents were studied,and the technology of extracting purplish red pigment from Solanum nigrum with resins was determined,and the preperties of the purplish red pigment was checked.The results showed that AB-8 resin had better adsorption and desorption effect on the Solanum nigrum purplish red pigment.In the course of desorbing the absorbed pigment for 100 min,50% ethanol was optimal,the colority E(1%,540 nm) was 35 and the product receiving rate was 1.26%.AB-8 resin was selected during the experiment.After repeating 20 times,the absorption factor had only a loss of 1.45%.Under this extraction condition,the pigment dissolved in water,but it was stable in acid solution.The light,heat lower than 80 ℃ and low density food additions also had no evident influences on its stability,Na~+,K~+,Ca~(2+),Mg~(2+) and Zn~(2+) have no influence on the pigment fluid,but Cu~(2+) and Al~(3+) had the function of adding colour to the pigment fluid,Fe~(3+) could change the colour of the pigment fluid;Oxidizer H_2O_2 and reductant Na_2SO_3·7H_2O could speed up the degeneration of the pigment.