Study On The Application Of Egg Yolk Antibody In Toothpaste

Caries is one of the most common diseases in human being.The WHO has ranked it with cancer and cardiovascular diseases as the three major human diseases for prevention and treatment.Streptococcus mutans is the main cariogenic bacteria.In this thesis,Streptococcus mutans was used as antigen and white oil as adjuvant to passively immunize hens to produce specific egg yolk antibody(IgY)which was applied into toothpaste.The effects of surfactants,moisturizers,thickeners and friction agents on Ig Y activity and structure determined the most optimum formula for IgY active toothpaste.The key to the production of anti-caries IgY toothpaste is the maintainence of IgY activity.Therefore,the surfactants commonly used in toothpaste are sodium dodecyl sulfate(SDS),cocoamidopropyl betaine(CAB),sodium lauroyl sarcosinate(LS-30),and dodecyl dimethyl betaine(BS-12).Therefore,they were used to study the effects on the activity of IgY.The results of ELISA showed that SDS caused the loss of IgY activity,followed by LS-30.The results of differential scanning calorimetry(DSC)analysis proved that IgY with SDS and LS-30 had been denatured before heating.But the denaturation temperature of IgY with CAB increased by 2.4?,and the enthalpy slightly increased.So,the heat resistance of IgY was enhanced.Therefore,CAB was selected as the most suitable surfactant in IgY toothpaste.The activity and spectroscopy consequences displayed the optimum pH environment of IgY was 6-8.Because CAB is a zwitterionic surfactant that exhibits non-ionic properties in neutral environment and reduces it ability to interact with IgY.So the pH 7.0 was chosen as the microenvironment of toothpaste system.The effects of SDS and CAB on the structure of IgY were compared by the UV fourthorder derivatives and fluorescent spectrum.When the concentration of SDS was more than 0.001 g/m L,the characteristic absorption peaks of Trp,Tyr,and Phe in IgY were blue shift,and generated the static fluorescent quenching.The curve fitting analysis concluded that SDS and IgY were combined to form a non-fluorescent complex.The concentration of SDS formed critical micelle concentration in IgY solution was much higher than CAB,which indicated more SDS monomers were combined with IgY.And the hydrophobic interation was the main force.The FTIR revealed ?-helix and ?-sheet contents of IgY with SDS decreased,and the secondary structure was destroyed.IgY,mixed with CAB,didn't undergo fluorescence quenching,and there were no changes in four secondary structure basically.Secondly,this paper studied the effects of moisturizers commonly used in toothpaste on activity and structure of IgY.Glycerol and 70% sorbitol had the least influence on IgY activity.Combined with spectroscopic analysis,PEG-400 and 600 made IgY quenching.The higher the concentration was,the more obvious the quenching effect was.Therefore,glycerol and sorbitol were selected as the glycerin agents in the bioactive toothpaste.The bioactive toothpaste not only needs to ensure the activity of IgY,but also needs to have good rheological properties.Therefore,this paper further studied the effects of different thickeners on the activity of IgY and the rheological properties of the compound system of different moisturizers and thickeners.When the amounts of xanthan gum and guar gum were both 0.5%,and glycerol and sorbitol were 25% and 35%,the colloid preoperties were the best by indirect-ELISA,texture,and rheology methods.Finally,the effects of different friction agents(silica,calcium carbonate,and calcium hydrophosphate)on the toothpaste system were investigated.The apparent structure of toothpaste was taken by the positive fluorescent microscope,suggesting that the structure of the silica type toothpaste was enenly distributed.The effects on IgY activity was minimal.The most suitable formulation provides a theoretical basis for the application of IgY in toothpaste.This can expand the application scope of IgY in the field of daily chemical industry.