Study On Extraction And Stability Of Pigments Of Chrysanthemum Cornarium L. And The Effect Of Soil Cadmium Pullution On Pigment Quality

The yellow pigments were extracted from the flower of Chrysanthemum cornarium L. Different solvents were used to extract the pigments. The optimum solvent was determined as water. The optimum extraction conditions including pH, temperature, ratio and time were studied by single factor experiment and orthogonal test L9 (34). The results showed that the optimum extract of yellow pigment was obtained under the conditions of pH 5.0, 50℃, 1:20 the ratio, and 5 hours.The pigment extracts were purified on different resin adsorbent columns. HZ818? nonpolar resin had the best effectiveness on purifying the extracts. The adsorbent volumn was 26.1 AV/g. 90% enthanol was determined as the optimum eluant, as its eluant rate was 97.98%.Thin Layer Chromatography (TLC) analysis of the extract showed the presence of flavonoids. The total flavonoid content was 750.67±8.65 mg/g in the extract, which was about 37.53mg/g in the dry flower of C. cornarium.The stability study showed that the pigment is moderately stable under high temperature in a short time. The extract was found to be more stable in lower pH.When pH is higher than 7, the pigment color is changed to red. The pigment's stability to metal ions is high, only Fe3+ has an obvious effect on the color of the pigment. Food addictives such as citric acid had no significant effect on the stability, while reductant-oxidant has significant negative effect on the stability. To study the comprehensive effect of different factors on the pigment stability, the thermal and light stability of the extract was tested at pH 3.0 and 5.0. At pH 3.0, the colour retention was 91% and 73% of after 8 h of heating at 50oC and 90oC. At pH 5.0, the colour retention was 79% and 65% at 50oC and 90oC. Light had a highly negative (P<0.01) effect on the stability. After 30 days of persistent illumination, the colour retention was 53% and 45% at pH 3.0 and 5.0.Study on the effect of soil Cd pollution on pigment quality demonstrated that though Cd content in pigment increased as the soil Cd content increase, the overall Cd content in pigment was low, all lower than 0.5mg/kg. When Cd content in soil was 0-1.0mg/kg, the Cd content in pigment had no significant change.In summary, the study on C. cornarium pigments'extraction, stability and soil Cd pollution effects provides the foundation of the further study of the pigments.