Study On Processing Technology And Characteristics Of Pumpkin Powder

Pumpkin has high nutrition and healthcare function,and is one of the main vegetables during summer and autumn in China.Pumpkin powder which is the most main processed product of pumpkin series products has strong market requirements and broad prospects.The processing technology and characteristics of pumpkin powder were researched in this paper,through optimizing the suitable conditions of color retention treatment with pumpkin,pumpkin pulpenzymatic hydrolysis and pumpkin powder drying,and comparing the physical properties and antioxidant activities of pumpkin powders treated with different technology.Firstly,the pumpkin slices were treated by blanching,steam heating and microwave heating.The three kinds of color retention treatments were compared to PPO relative activity and color difference.The results showed that the PPO relative activity of pumpkin slices treated with microwave heating was the lowest,and the effect of color protecting was good.Based on the above researches,the microwave heating conditions were researched by single factor and orthogonal experiments.The results showed that the optimum microwave heating conditions were as follows:the microwave time was three minutes,the microwave power was 390 w,and the slice thickness was 5 mm.Treating with the optimum conditions,the PPO relative activity and the color difference of pumpkin slice were 22.87%,3.76.Secondly,with soluble sugar as evaluation indexes,the optimum enzymatic hydrolysis conditions of pumpkin pulp were researched by single factor experiment and response surface analysis.The result showed that the best composite enzymatic hydrolysis was the amount of pectinase,?-amylase and glucoamylase were 0.02%,0.53%and 0.89%.The content of soluble sugar was 5.38%in this condition.On the basis of the optimal mixture enzyme ratio,using the uniform design method to study the enzymolysis process conditions,identified with enzyme solution temperature,enzymolysis time,shaking speed for process conditions is:enzyme solution temperature was 60?,enzymolysis time was 2.5 h,shake speed was 120 r/min,the soluble sugar content in pumpkin pulp is 5.55%.To further study about the effect of microwave on hydrolysis,single factor and orthogonal experiments were conducted.Results showed that after enzymatic hydrolyzing 1 h,selecting microwave power 230 w for 3 min,soluble sugar content could reach 5.83%Thirdly,the quality of pumpkin power prepared by microwave drying,vacuum drying and vacuum freezing drying were compared.Results showed that the quality of pumpkin power prepared with vacuum freezing drying was the best,and the V_Ccontent,?-carotenecontent,total phenolscontent,soluble sugar content and sensory value,angle of repose,solubility,volume-weight,water holding power,oil holding capacity,DPPH radical scavenging activity were 114.5 mg/100g,32.2 mg/100g,3.83 mg/g,6.43%,85,37.7°,0.231%,0.7076 g/mL,5.63g/g,4.77 g/g,88.76%,respectively.Finally,the nutritional,physical,antioxidant properties of pumpkin powder A and B(pumpkin powder A was prepared by fresh pumpkin treated with beating,vacuum freezing drying,and pumpkin powder B was prepared by fresh pumpkin treated with color retention,enzymatic hydrolysis,vacuum freezing drying)were compared and analyzed.Results showed that pumpkin powder B had a greater quality than pumpkin powders A.