Effects Of Gastrointestinal Digestion On Immunoreactivity Of Glycosylation Soybean Antigen Proteins

Because of its high nutritional and functional properties, soybean is widely used in food and feedindustry. However, soybean antigen proteins can cause allergic reaction in infant, piglets, calves and otheryoung animals.Therefore soybean is considered to be one of the major food allergens.Glycinin andβ-conglycinin are two major antigen proteins in soybean and they accounted for about65%to80%of the totalseed protein.This study was done in order to utilize the method of glycosylation which could reduce theimmunogenicity of soybean antigen proteins, and determine the immunogenicity variation of the glycosylatedsoybean antigen proteins through system-wide anlaysis in vitro and in vivo. Firstly, fructo-oligosaccharide(molecular weight=741.9) and rough glycinin or β-conglycinin was mixed at molar mass ratio of1:14andwith the temperature and relative humidity (RH) combinations (65℃，75%RH). Reaction products werecollected after60h, respectively. The solubility of proteins and the immunogenicity of these samples weredetected. Secondly, the immunogenicity variation of the glycosylated soybean antigen proteins afterhydrolyzed at various hydrolysis time (0.5,1,15,30,60min) and enzyme substrate ratio (1:20,1:10,1:1,10:1)were analysed in vitro. At last, the immunoreactivity disapearance rate of glycosylated soybean antigenproteins in the digestive tract of piglets and their effects on the growth performance of piglets were evaluated.Generally, the results showed that the immunogenicity removal increased in all products as time went on, andthe removal rate reached75%more or less at60h. The enzymatic hydrolysis experiement in vitro showed thatthe immunogenicity residual rate of unglycosylated soybean antigen protein was much higher than those ofthe glycosylated soybean antigen proteins.The pepsin and trypsin hydrolysis glycosylated glycinin andglycosylated β-conglycinin in a different way. In the in vivo test, the immunoreactivity disapearance rate ofthese soybean antigen proteins was found similar to those in vitro, but some difference was found betweenglycosylated and unglycosylated proteins on the growth performance of weaning piglets. The weaning pigletswhich fed glycosylated proteins were a little better on the average daily gain than unglycosylated.Theseresults demonstated that the immunoreactivity of glycosylation soybean antigen proteins would not recover bygastrointestinal digestion, and the hypoallergenic glycosylation soybean antigen proteins showed theirapplication prospect in piglet production.