Effects Of Superfine Grinding On The Nutrients Rate And Antioxidant Activity Of Pumpkin Powder

Pumpkin is gourd melon genus of annual tendril herb. And it is widely planted in our country.Pumpkin pulp is rich in a variety of nutrients, including sugar, vitamin, protein, amino acids, fatand other active substances. The capacity of pumpkin production in China is high, but pumpkinproducts processed by traditional method tastes rough and less nutrient, so it is significance todevelop a new processing method to keep its active ingredients and to improve its taste and toenhance its functions.It was studyed that pumpkin crude powder and superfine powder processed by grinding millas sample in the experiment to discusses the effect on the protein solubility, polysaccharide anddietary fiber extraction yield and antioxidant activity of different processing powder, the followingconclusions:(1) It was found that the protein solubility of crude powder changed slightly with dissolvedtime and the dissolution rate was low, a maximum of34.41%, and protein solubility of superfinepowder increased with time, a maximum of61.34%; Overall, the protein solubility of superfinepowder was higher than crude powder.(2) The polysaccharide of the crude and superfine powder was extracted by water.It wasstudied that the effect of various process parameters in the extraction process on pumpkinpolysaccharide yield. The influence degree of various factors on the polysaccharide yield of crudepowder were in turn: extraction temperature, extracting time and liquid ratio, and optimal processconditions were extraction temperature80℃, the extraction time4h, liquid ratio50:1.Thepolysaccharide extraction rate was verified12.62%. The influence degree of various factors on thepolysaccharide yield of crude powder were in turn,extraction temperature, time and liquid ratio,and the optimal process conditions were extraction temperature80℃, extracting time2h, liquidratio60:1.The polysaccharide extraction rate was verified15.86%.(3) The method of microwave-assisted extraction was adopted to extract the polysaccharide ofthe coarse powder and superfine powder.It is discussed that the effect of various parameters on theyield of polysaccharide. The influence of various factors on the polysaccharide yield of crudepowder were in turn, liquid ratio,extraction time and temperature, and the optimal processconditions were liquid ratio25:1, extracting time40min, extracting temperature70℃,Thepolysaccharide extraction rate was verified14.96%. The influence of several factors on the polysaccharide yield of superfine powder was: liquid ratio, extracting time and temperature, andthe optimal process conditions were: liquid ratio25:1, extracting time20min, extractiontemperature70℃.(4) It was studied that the effect of various parameter on the yield of soluble dietary fiber inthe extracting process of crude powder and superfine powder. The influence of various factors onthe yield of coarse powder as follows: pH, extraction time, extraction temperature and liquid ratio,and the optimum parameters of coarse powder were: extraction temperature100℃, extractiontime1h, liquid ratio25:1, pH2, and the dietary fiber extraction yield was15.34%. The influenceof various factors on extraction yield of ultrafine powder as follows:extraction temperature, liquidratio, extraction time, pH, and the optimum parameters were: extraction temperature70℃,extraction time1h, liquid ratio45:1, pH2, the yield of dietary fiber was31.52%.(5) The screening ability to free radicals in crude powder and superfine powder was studied.Itwas found that the antioxidant activities of the coarse powder and superfine powder were on somedegree, and the effect of superfine was better than the coarse powder and superfine powder.(6) It was found in SEM that the surface was smooth and spherical for the surface of pumpkinpowder by ball grinding time for2h. The spherical structure of pumpkin powder for4h by millingwas destroyed into fragmentary pieces. The spherical structure of pumpkin powder for6h bymilling was dispeared into small size powder, and the reunion phenomenon in a powder wasexisted. And the structure of the pumpkin powder for8h by milling was presented flaky, thereunion phenomenon in a powder was severe and not dispersed.