Study On Extraction And Purification Of Glycoprotein From Purple Ipomoea Batatas And Antioxidant Functions

Purple sweet potato (purple ipomoea batatas) is a new specie introduced from Japan,which contains abundant of glycoprotein. Present Science research suggest that glycoprotein can give special protection function to human's health, It could be to protect gastrointestinal mucosal and maintain respiratory tract moist. It could be to prevent arteriosclerosis due to accumulation of Lipids on the Artery wall and prevent atrophy of connective tissue in liver and kidney. It assumed to Anti-aging for human's organ and enhance immunity. In this paper, glycoprotein was extracted by ultrasonic from purple ipomoea batatas, and the glycoprotein was purified using DEAE-52, G-75 gel. Then the antioxidant activity of glycoprotein was studied in vitro. For purposes of utilize Purple sweet potato to provide theoretical guidance and process parameters. The main results are as follows:1,Glycoprotein was extracted from the purple sweet potato with the ultrasonic-assisted extraction in this paper. The protein content of glycoprotein was calculated with the bovine serum albumin as standard reference. Ultrasonic power, the ratio of solid to liquid, extraction times and ultrasonic time was chosen as main factors in orthogonal experimental design, the result analysis of variance and multiple comparison. The result showed that the main extraction influence factors of purple sweet potato glycoprotein in turn were extraction times, solid to liquid ratio, ultrasonic power and ultrasonic time; Through the analysis of variance, the three single factor of extraction times, solid to liquid ratio and ultrasonic power differences were extremely significant, the ultrasonic time was not significant; The best conditions of extraction are conducted after multiple comparisons and validation test when the power of ultrasonic is 150 W, the ratio of raw materials is 1:10, the times of extraction is 3 times, the extraction's time is 30 min. It obtained best result of extraction 0.4529% from purple sweet potato.2,The glycoprotein of purple sweet potato was obtained using ethanol precipitation several times and Sevage method to eliminate the free protein, then the glycoprotein was freeze-drying in vacuum. The glycoprotein was extracted by DEAE-52 cellulose column chromatography with NaHCO3 gradient elution of 0.05,0.10,0.20,0.30,0.40,0.50 mol/L respectively. The overlapping peaks of glycoprotein eluating was collected to dialysis and vacuum freeze-drying, then the red raw glycoprotein powder was obtained.This glycoprotein powder was Chromatography by SephadexG-75 Sephadex, eluting with double distilled water. The eluate of overlapping peaks was collected to dialysis and vacuum freeze-drying, then the white glycoprotein powder.3,The antioxidant activity of purple sweet potato glycoprotein was evaluated by superoxide anion free radical (O-2.), hydroxyl free radical (·OH) and 1,1-diphenyl -2-phenylhydrazine radical (DPPH·).The result showed that the glycoprotein powder has significant antioxidant activity in the range of 0-640μg/mL concentration, and the activity was enhanced with the increased concentration. when the concentration of glycoprotein was 640μg/mL, the clearance effect to superoxide anion free radical could reach to 69.80%.