Research On Extraction And Modification Of Pumpkin Seed Protein

In this study,with pumpkin seed meal obtained by cold-processed method as material and pumpkin seed meal protein was prepare with ultrasonic-assisted alkali-soluble acid precipitation extraction method.The optimal extraction process was established,transglutaminase was used to modify the protein of pumpkin seed meal,and the function of the modified protein was studied.The aim is to improve the utilization value of pumpkin seed meal protein and lay a theoretical foundation for the intensive processing of pumpkin seed meal.The main results are showed as follows:The extraction process parameters of pumpkin seed meal protein had been determined.The pumpkin seed meal protein was extracted by ultrasonic-assisted alkali.The optimal extraction process conditions were determined by single factor experiment and response surface experiment design:Material to liquid ratio:1:30?reaction pH:11?reaction temperature:30??reaction time:1h.In such conditions,the highest extraction rate and purity are 80.64% and 88.65%.Pumpkin seed meal protein components are: albumin 12%,globulin 26%,gliadin 8%,glutenin 54%,isoelectric point is pH=5,and the relative molecular weight mainly concentrated in 20 KDa and 35 KDa.The enzyme modification process parameters had been determined.Pumpkin seed meal protein was modified by transglutaminase(TG enzyme).The optimum technological conditions were determined by single factor experiment and response surface design.The optimum conditions were as follows: enzyme dosage 30U/g,reaction temperature 40?,reaction time 2.5h,and the optimum gel strength was 90.71 g.The functional properties of pumpkin seed meal protein modified TG enzyme had been research.The solubility of pumpkin seed protein was 8% at pH=5 and 13% after TG enzyme modification;the water content of pumpkin seed protein was 1.5 g/g at pH=5,and 2.9 g/g after modification;pumpkin The emulsifying and emulsifying stability of seed protein was 40% and 32.8% at pH=5,and the emulsification and emulsifying stability of 34% and 26.4% after TG enzyme modification;pumpkin seed The foaming and foam stability of the protein was 5.31%,14.2% at pH=5,and the foaming and bubble stability after TG enzyme modification were 9.64% and 30.16%.After modification,the indexes of Water retention,oil absorption,emulsification,emulsifying stability and foam stability of pumpkin seed meal protein were more than those of soybean protein under neutral conditions.The water content of the modified pumpkin seed protein was increased by 0.2g/g,the oil absorption was improved by 1.1g/g,the emulsifiability was improved by 4%,the emulsion stability was improved by 19.3%,and the foam stability was improved by 6.51%.Solubility and foaming ability was lower than that of soybean protein.Its solubility decreased by 51% and foaming decreased by 45.89%.