Study On The Improvement And Application Of Yeast β-glucan Solubility And Emulsification

Yeast β-glucan has received wide attention due to its good biological activity.The Ministry of Health of my country has approved β-glucan as a new resource food,and the European Fo od Safety Association(EFSA)has approved β-glucan preparation as a new resource food ingred ient.But its unique triple helix structure and imbalance of hydrophilic and hydrophobic groups result in its insoluble in water and poor emulsification,which limits its application in the fields of food,medicine and cosmetics.The establishment of β-glucan modification technology to im prove solubility and emulsification,which expands its application in beverages,meat products a nd other food fields.It is of great importance to promote the high-quality development of the i ndustry and improve the nutrition and health of the whole people.The optimal process parameters of β-glucan enzymatic solubilization were optimized: β-gluc an concentration was 15 mg/m L,temperature was 45℃,time was 83 min,and the amount of enzyme added was 4.3%.The optimal process increased the solubility of WSG from insoluble t o 89.74±0.62%.Optimize the process parameters of β-glucan,peanut protein isolate and soybea n protein isolate by Maillard reaction grafting modification,and prepared WSG-PPI/SPI conjugat es.The optimal process conditions of WSG-PPI conjugate were:p H 9,Time was 80 min,temp erature was 90℃,PPI/WSG was 1:3,and WSG concentration was 3 mg/m L.Compared with β-glucan,the emulsification of WSG-PPI conjugate was increased by 7.9 times.Compared with P PI,the emulsification of WSG-PPI conjugate was increased by 5.6 times;the best preparation c onditions of WSG-SPI conjugate were:p H 9,time was 180 min,temperature was 95℃,SPI/W SG was 1:3,WSG concentration was 3 mg/m L Compared with β-glucan,the emulsifying proper ty of WSG-SPI conjugate was increased by 6.5 times,and compared with SPI,the emulsifying property of WSG-SPI conjugate was increased by 3.3 times.The changes in the physical and chemical properties of β-glucan and its conjugates before and after modification were clarified. β-glucan undergone enzymatic hydrolysis and solubilizatio n,and the molecular weight was reduced from 6.09?10~6 g/mol to 2.99?10~6 g/mol,6.68?10~4 g/mol and 1.40?10~4 g/mol;The molecular weight of WSG-PPI conjugate was 4.08?10~6 g/mol and4.03?10~4 g/mol,and the molecular weight of WSG-SPI conjugate was 3.52?10~6 g/mol and 5.58?10~4 g/mol by Maillard reaction.Thermogravimetric analysis showed that WSG had better ther mal stability than β-glucan,and the thermal stability of WSG-PPI conjugate and WSG-SPI conj ugate were better than that of WSG;Rheological results showed that enzymatic hydrolysis redu ced β-glucan,and the grafting modification increased the viscosity of WSG-PPI conjugate and WSG-SPI conjugate.The structural changes of β-glucan and its conjugates were studied.The primary structure of β-glucan did not change before and after enzymolysis,and it was still connected by β-1,3-gl ycosidic bonds;CD results showed that the modified WSG still had a highly ordered structure,and haddα-helix and similar to β-sheet structure,which was conducive to contact with water molecules to improve solubility;SEM and CLSM observed that after enzymatic hydrolysis modi fication, β-glucan changed from an aggregated clump structure to a broken sheet structure,and the particles size reduced.After graft modification,FT-IR showed that WSG-PPI conjugate and WSG-SPI conjugate were formed;CD results showed that the positive absorption peak of WSG-PPI conjugate and WSG-SPI conjugate decreased,the negative absorption peak increased and moved to the left,which meaned its conformation had changed;CLSM and SEM results showe d that the surface of the WSG-PPI and WSG-SPI conjugates were rougher,indicating that WS G was attached to the surface of the protein.The effects of β-glucan,WSG,WSG-PPI conjugate and WSG-SPI conjugate on the quality of sausages were compared.Comprehensive consideration,when the WSG-PPI compound replac es 20%fat,the yield rate of sausage was 88.60%±2.79%,the water loss rate was 20.92%±1.93%,L~*was 66.20±0.37,a~*was 3.67±0.21,b~*was 15.39±0.64,hardness was 7356.00±776.86,el asticity was 0.89±0.04,chewiness was 3346.22±376.36,cohesiveness was 0.51±0.06,water retent ion of low-fat sausage was better than commercial products,and texture was equivalent to com mercial products.