Bauhinia Natural Red Pigment Extracted And Refined Process

The new red pigment from Bauhinia aurea Levl was extracted by the method of surfactant assisted microwave extraction and purified by the technology of macroporous resin. The optimum conditions and stability of colorant were determined. The primary structure of the pigment was confirmed elementarily. The studies laid theoretical foundation for large-scale extraction and purification of the red pigment from Bauhinia aurea Levl.Through experiments, the optimum conditions of the extraction were determined as follows: microwave power was 648W, the extraction agent was 0.03% K₁2 solution, extraction time was 50s, the ratio of raw material to extraction reagent was 1:80g/ml, extraction times were twice, the yield of extracted pigment achieved 87.18%.The optimum conditions of the purification were studied. The optimum conditions were determined as follows: the best macroporous resin was X-5, the flow rate on dynamic absorption was 1 ml/min at normal temperature, the original concentration and PH of the flower solution was 2g/L at PH=2³. The best desorption reagent was acetone, the flow rate on dynamic desorption was 1. 5 ml/min at normal temperature. The yield of pigment achieved 3. 8% when the color value was 264.3.The stability of red pigment from Bauhinia aurea Levl has obviously enhanced after purification. It was sensitive to light, heat, oxidants, reducing agents, vitamin C and Fe³+. The red pigment was stable to Na⁺ K⁺ Mg²+ Cu²+ Ca²+ Zn²+ Al³+ and Sodium benzoic acid, Fe²+ Pb²+ can protect the extracted colorant.According its character and its different color in different PH, the red pigment was confirmed elementary as the anthocyanin. Analysising the UV Spectrum and the LC-MS Spectrum of the fine pigment, one main component of the pigment was Hirsutidin, its probable structure was as follows:...