Study On Graft Modification Of Artemisia Sphaerocephala Gum And Emulsification Of Its Products In Oil-in-water System

Artemisia sphaerocephala krasch gum is one of the important characteristic wild plants in northwest China.It is a kind of heteropolysaccharide extracted from artemisia sphaerophyllum seed.In recent years,the development of natural polysaccharide emulsifier has become a hot topic for food researchers,but the research on artemisia annul gum as a natural emulsifier is seldom discussed.Therefore,this study modified artemisia sphaerocephala gum on the basis of previous studies in order to obtain excellent emulsification products.In the O/W system,by graft modification of artemisia sphaerocephala gum and exogenous protein,the preparation process,structural function and emulsification stability of the product were studied.Specific research contents are as follows:(1)Study the modification technology of artemisia sphaerocephala polysaccharide.The single factor and response surface method was used to optimize the optimum process conditions of reaction:118min,temperature 90?,pH12.Under this condition,the absorbance value at 500nm emulsification was 0.732,and the emulsification stability was 244min.The results of the verification test are very close to the predicted values,indicating that the model fitting degree and reliability of the predicted emulsification and emulsification stability of the reaction are good.(2)Study the structure of graft products.Amino acid analysis showed that lysine and arginine in the products decreased by 23%and 31.1%respectively.These two amino acid changes can confirm the occurrence of the reaction.The SDS-PAGE experiment showed that the strength of these bands labeled with protein decreased,while the complex showed obvious bands at the boundary between the laminate and the separating gel,indicating the formation of high molecular weight substances.By fluorescence spectrum,the maximum fluorescence intensity of the product was lower than that of the original protein,this is due to the steric hindrance of protein fluorescence after the polysaccharide linked in.Through the characterization of FTIR-ATR,the peak intensity at 2928 cm-1 in Maillard reaction products was significantly reduced.Through the characterization of FTIR-ATR,the absorption of graft reaction products at 3,700 cm-1?3,200 cm-1 and 1260cm-1?1,000 cm-1 was higher than that of whey protein,which were the absorption peaks of hydroxyl and carbon-oxygen bonds respectively.The peak strength at 2928 cm-1 was significantly reduced,possibly due to the reduction of methylene vibration due to the interaction between protein and sugar molecules.(3)By scanning electron microscopy(sem)observation,colloid scanning electron microscopy(sem)images showed close layer structure,and graft products and the mixture show close block structure,compared with spherical structure formation of protein before reaction,which proved that the occurence of the graft reaction,and at the same time,microstructure change due to heat and non covalent.The particle size distribution analysis of high-speed shear treated emulsion shows that the particle size of MRPs emulsion is obviously smaller droplet distribution,which indicates that the graft product of artemisia sphaerocephala gum and whey protein has better emulsification.Through DSC analysis,the thermal denaturation temperature of MRPs was markedly higher than the MIX,and the denaturation temperature of MRPs increased from 55.97? to 73.4?.(4)The influence of modified artemisia sphaerocephala gum on the emulsification stability of milk beverage was studied.Combined with R value and conductivity,three groups of single factor tests were conducted to select the optimal dosage of modified emulsifier of sucrose ester,monoglyceride and artemisia sphaerocephala gum as 0.06%,0.04%and 0.04%respectively.The optimal dosage was selected for experimental observation during storage.During the storage period of 15 days,observe the stability of the three groups of beverage by measuring its R value,conductivity,centrifugal sedimentation rate,the viscosity and stability of sensory evaluation.Considering the above indexes,draw the conclusion:in the beverage,when emulsifiers single use,artemisia sphaerocephala krasch gum modified emulsifier is slightly better than sucrose esters and monoglycerides emulsification.