Study on Microwave-assisted Extraction and Application of Natural Red Pigment from Peel of Pitaya

With dry powder of pitaya peel as raw material,microwave-assisted extraction(MAE)method was studied for the extraction of a red pigment from the peel of Pitaya.The results showed that the maximum absorption wavelength of water solution of the pigment in the peel was 535 nm,the extraction was bright red.The suitable condition of extraction with ethanol as extracting solvent was as follows: the microwave was 180 W,the extraction time was 60 s and the optimum material-to-liquid ratio was 1∶ 60 g/mL.The MAE method is a fast,efficient,energy saving method,which is recommendable for the application on the extraction of natural red pigment from the peel of Pitaya.When the red pigment crude extract from the peel of pitaya was 80 mg/100 g,the jelly was the best;when the red pigment content was 23 mg/100 mL,the experimental mixed wine being and the purchase was similar,presented pink.The red pigment disappeared after a month which in the jelly and mixed wine by stored at room temperature without avoiding light.Vitamin C has a protective degradation effect on red pigment of the jelly.The red pigment should be preserved in dark place at low temperature.