The Effect Of Reverse Micelle On The Subunit Structure And Functional Properties Of 7S And 11S Globulin In Soybean Protein

As a vegetable protein,soy protein is not only rich in resources,its protein digestibility is equal to or even beyond animal protein.For human body,it is a kind of high quality protein,which can play the role of good nutrition and healthcare.The proportion of 7S globulin in soybean protein is 35%,that of 11 S globulin is 52%,and they are the most important components in soybean protein.Soybean 7S globulin contains ?'(58kDa)subunit,?(57kDa)subunit and ?(42kDa)subunit,and 11 S globulin contains acidic subunit(35-37kDa)and basic subunit(20kDa).Taking soybean 7S and 11 S globulin as well as ?',?,?,acidic and basic subunits as main research objects,the separation and preparation of research objects,subunit extraction process with AOT/normal hexane as reverse micelle system and the subunit structure prepared in reverse micelle system and functional properties were studied in the paper.The main contents are as follows:1.Taking soy protein isolate(SPI)as raw materials,the cryoprecipitate method of isoelectric point was adopted to prepare soybean protein.The yield of 7S globulin was about 7.3% with the concentration of 91.1%,that of 11 S globulin was about 21.1% with the concentration of 88.1%,and both of their concentrations were better than that of protein prepared with traditional Nagano method.2.SDS-PAGE gel electrophoresis was used to extract and purify subunits,the purities of ?' subunit,? subunit and ? subunit of 7S globulin were 69.24%,89.96% and 87.87%;and the purities of acidic subunit and basic subunit of 11 S globulin were 73.11% and 74.96%.3.For the forward extraction process of preparing subunits with reverse micelle,the optimum forward extraction temperature was maintained at 45?;the best extraction water activity of ? and ? subunits was W0=13,and that of other subunits was W0=18;the effect of reverse micelle concentration on forward extraction rate was significant,and the optimum reverse micelle concentration was 0.08-0.1g/ml;pH should be kept in the range of 7.0-8.0;the forward extraction time was relatively short,in the range of 50-80 min.In the backward extraction process,the extraction temperature of 7S globulin subunit was 40-45 ?,and that of 11 S globulin was relatively low,about 20-35 ?;the concentration of KCl had a significant effect on backward extraction rate,and the optimum concentration of KCl was 0.6-0.8mol/L;pH should be kept in the range of 7.5-8.5;the backward extraction time was relatively long,in the range of 90-120 min.4.Through experiments and optimization of response surface,the optimal forward extraction rate and backward extraction rate with reverse micelle extracting subunits were: ?' subunit 78.21% and 67.46%,? subunit 63.65% and 61.03%,? subunit 61.34% and 71.40%,acidic subunit 59.53% and 73.61% and basic subunits 57.74% and 71.47%.5.7S and 11 S globulin subunits prepared by reverse micellar system have good emulsibility,stability,foamability and higher nitrogen solubility index,which can be applied in the field of food better.