Study On Extraction、Purification And Stability Of Red Pigment From Pitaya Peel

Research on the red pigment of pitaya peel haven’t been much.The paper alanalysis the following parts:extraction pigments of pitaya peel,purify pigment method by adsorption resin, the stability of pigment.The main conclusions are as follows:1、the red pigment extracted by solvent extraction method to discuss the suitable condition as follows:the ethanol concentration was35%, the pH value was4, the extracion temperature was30℃,the optimum material-to-liquid ratio was1:8, The best red pigment extraction rate of pitaya peel was7.36%. The suitable condition of Supersonic-assisted extraction(SAE)method as follows:extract supersonic power was75w,extraction time was40min,the ratio of solid to liquid was1:12. The best red pigment extraction rate of pitaya peel was7.76%. SAE method was better than solvent extraction method by comparision.2、AB-8was the optimum resin of adsorption resin method.By adsorption experiment the optimum condications show:pH value was4, adsorption time was60min, flow rate of liquid was5mL/min.By desorption experiment the optimum condications show:30%alcohol was the elution, desorption time was40min,the volume of elution was400mL.the colour value of red pigment was27.71,It’s5.2times as much as unpurify.3、The stability of red pigment under different conditions such as temperature, pH, light, oxidants, antioxidants, food additives and metal ions was studied in this paper. The results show that:temperature above50℃、Ultraviolet light decreased its stability, but visible light had no effect on the stability of the pigment.The red pigment was stable in acid, Oxidants and reducers could make the pigment discolor or fade. Some metal ions such as Ca2+、Mg2+、Na+and K+made the pigment deepen its color and raise its stability.