Study On The Preparation Of Pumpkin Polysaccharide And Pectin And Pumpkin Powder From Pumpkin

Pumpkin is a common vegetable in our life. The resource of Pumpkin is richin our country, and the price is low. Pumpkin, which contains abundant nutrients,has good edible value as well as unique medicinal value. Its major nutrientsincludes polysaccharides, pectin, and dietary fiber. In this paper, we studied theextraction, the purification and the antioxidant properties of pumpkinpolysaccharide and utilized the pectin and rich flavor of pumpkin powder fromthe rest of the extract of pumpkin polysaccharide. The main experiments are asfollow:1、Through the extraction by acid process, the experiments showed that thebest extraction conditions of pumpkin polysaccharide are at the pH value is6.0,extracting temperature is50℃,extracting time is1.5h,the ratio of material tosolvent is1:3. Extracted two times on these conditions, the extraction rate is93.38%.2、In this paper, the membrane technology is used to purify the Pumpkinpolysaccharide extraction liquid. We determined membrane type by contrastexperiment. The separation and purity removal were done bytwo-order-membrane technology. The experiments show that the membranemodule could run steadily and maintain a high penetration capacity. Finally, thepurity of pumpkin polysaccharide is91.36%.3、In order to prove pumpkin polysaccharide has free radicals scavengingability, three kinds of radicals（DPPH、 OH and O₂）were used to do the study.The results showed that pumpkin polysaccharide has the capacity of scavengingfree radical and its effect increased with amount of pumpkin polysaccharideincreasing. The maximum clearance rate of radicals（DPPH、 OH and OR2-RPP）are68.13%、58.37%and47.83%.4、 To analyzed the pumpkin dregs, which was extracted pumpkinpolysaccharide. The results showed that the pumpkin dregs contains a largenumber of pectin. We extracted Pumpkin pectin from pumpkin dregs with acid.The optimization experiments showed that the best extraction conditions of pectinare as follow: The pH is2.5,extracting temperature is90℃,extracting time is2.0h,the ratio of material to solvent is1:4. Under these conditions, the extractionrate is93.69%.5、Membrane technology is used to remove the impurity and to purify thepectin extraction liquid. The separation and purity removal were done bytwo-order-membrane technology. Finally,the purity of pectin is88.56%. Theobtain pumpkin powder is canary yellow, which obtained from the concentrated solutionby alcohol precipitation and vacuum drying.6、Study on the pumpkin pomace and membrane filtrate with comprehensive experiments. The experiment used heterogeneous machines to handle them. Theexperiment show that pumpkin powder contains a large number of nutrientsubstance, it can be used as excipients or additives.In this thesis, the main research is about the preparation of pumpkinpolysaccharide and pectin and pumpkin powder from pumpkin. The wholeprocess is in accordance with the Circular Economy and Clean production as thecenter.