Extraction,Purification,Physical And Chemical Properties And Antioxidant Activities In Vitro Of Polysaccharide From Amaranthus Hybridus L.

Amaranthus hybridus L.is an annual herb of Amaranthus Amaranthceae,which is also a kind of food,vegetable and forage crop.The main medicinal effects of amaranth is clearing heat,promoting defecation and urination,treating red and white dysentery,anuria and constipation.This study with A.hybridus L.on the ground part for material,with traditional hot water,microwave-assisted hot water and ultrasonic-assisted hot water three methods for A.hybridus L.polysaccharide(AHP),the optimum extraction process was optimized by RSM.The physical and chemical properties and its antioxidant activity in vitro were analyzed and the relationship between physicochemical properties and biological function was analyzed.The results of this study can promote the effective utilization of the amaranth resources,and provide the theoretical basis for the development and utilization of AHP's products.The main results are as follows:1.The traditional hot water extraction method,the microwave assisted hot water extraction method and the ultrasonic assisted hot water extraction process were optimized,and the crude polysaccharide was obtained by water extraction and alcohol precipitation method.The optimum extraction process is microwave-assisted hot water extraction.The extraction time was 47 min,the extraction power was 210 W,the ratio of material to liquid was 1:31(g/mL),and the actual yield was 12.98%±0.13%.2.The results showed that the crude polysaccharides extracted from the three methods had different contents in the content of neutral polysaccharides,uronic acid and protein,but all of them contained high content of uronic acid,which indicated that AHP was an acidic polysaccharide.FT-IR results showed that the crude polysaccharides obtained by the three methods had the saccharide characteristic groups.UVS results showed that the crude polysaccharides contained protein or nucleic acid.The results of SEM showed that the structure of crude polysaccharides were extracted by hot water extraction method(AHP-H)and microwave extraction polysaccharides(AHP-M)tightness,the surface of the AHP-H is smooth,the surface of the AHP-M has a small protrusion,and the ultrasonic extracted polysaccharide(AHP-U)is loose and uneven.Ultrasonic method is very destructive to the polysaccharide surface structure,and the other two methods have less damage to the surface structure of the extracted polysaccharide.3.Crude polysaccharides in vitro antioxidant results showed that the three methods of crude polysaccharides have antioxidant activity in vitro,which AHP-H has the highest activity.The scavenging rate of DPPH radical was 72.2%,the scavenging rate of hydroxyl radical was 41.8%,the superoxide anion free radical scavenging rate was 68.3%,and the absorbance value of Fe3+ was 1.16 in 2 mg/mL AHP-H solution.The total antioxidant capacity of T-AOC per mg of AHP-H was 4.2,which was close to the total antioxidant capacity of Vc 4.5.4.A total of 6 kinds of purified polysaccharides were isolated and purified from the crude polysaccharides from the three kinds of methods.They were named AHP-H-1,AHP-H-2,AHP-M-1,AHP-M-2,AHP-U-1 and AHP-U-2 respectively.The purified polysaccharide neutral polysaccharide,uronic acid and protein have biggish difference content;The FT-IR results showed that there was no difference in the functional groups between the crude and purified polysaccharides.UVS analysis results show that the protein and nucleic acid content in the purified polysaccharide is few,purification can be very good to remove the protein and nucleic acid material in the crude polysaccharide;GC-MS results showed that the monosaccharide content exists obvious difference between samples,the AHP-H-1 contains the largest variety(7)the monosaccharide components,the AHP-M-1 only contains three kinds of monosaccharide composition.5.Purification of polysaccharide in vitro antioxidant results are as follows:AHP-H-2 was more effective than AHP-M-2 and AHP-U-2 in vitro,and the antioxidant activity of polysaccharide was higher than that of AHP-H-2.The scavenging rate of DPPH radical was 80%,the scavenging rate of hydroxyl radical was about 48.5%,the scavenging rate of superoxide anion was 85.3%,and the absorbance of Fe3 + was 0.92.The total antioxidant capacity of T-AOC per mg of AHP-H-2 was 6.5,which was stronger than the total antioxidant capacity of Vc 4.5.