| Mesona chinensis Benth.,also known as Salvia miltiorrhiza,fairy grass,fairy grass,fairy grass,etc.,is a plant of the genus Jellyaceae.As a traditional medicinal and edible plant,it has the effects of relieving heat,quenching thirst,clearing the lungs and lowering blood pressure.Mesona chinensis polysaccharide(MCP)is an acidic heteropolysaccharide extracted from Mesona chinensis with gelatinous properties,which has the effects of anti-oxidation,immune regulation and blood sugar lowering.In the liquid state,the MCPexhibits Newtonian fluid or pseudo-plastic fluid behavior.A single polysaccharide cannot form a gel alone,and needs to interact with protein,starch or other substances to form a gel.Whey protein isolate(WPI)is known as the "king of protein" and has extremely high nutritional value.A single WPI only forms a thermosetting gel at a high concentration(≥12%).Polysaccharides and proteins are important components in foods,which play an important role in the structure and properties of foods.It is of great significance to study the effect of polysaccharide and protein compounding systems on the microstructure and texture characteristics of foods.However,there is relatively little research on the blending between MCP and WPI.The interaction between them and the effect of calcium ions on the properties of the composite gel system are still unclear,and the mechanism of gel formation between protein and polysaccharide is not yet clear.Therefore,this paper first explored the conditions for the formation of gels in the compound system of MCP and WPI,and measured the gel properties of the compound gel of MCP-WPI.The analysis of its interaction force and microstructure revealed its gel formation mechanism.In addition,on this basis,its practical application was studied,and a new jelly grass-containing milk jelly could be developed.The main results are as follows:1.The functional properties,thermal stability,rheology,texture characteristics and microstructure of the MCP-WPI gel were studied.The results show that the MCP-WPI composite gel has a higher WHC than the WPI gel.As the concentration of MCP increases,the gel structure becomes denser,resulting in a gradual increase in WHC and an increase in thermal stability and thermal transition temperature.Under alkaline conditions,MCP-WPI has a higher thermal transition temperature and thermal stability.The addition of calcium ions has little effect on the thermal stability of the system.The apparent viscosity,loss modulus(G"),storage modulus(G’)and creep recovery capacity of the MCP-WPI composite gel increase with the increase of MCP concentration and increase with the increase of pH,decreases with the increase of calcium ions.The MCP-WPI composite gel shows good elasticity and rigid structure.Texture texture analysis(TPA)results show that adding MCP or increasing the pH can increase the gel strength and fracture stress,but the effect of adding calcium ions is the opposite.Scanning electron microscopy(SEM)results show that at pH 10 and MCP addition of 2.0%,it has a good three-dimensional network structure.Low pH conditions and the addition of calcium ions cause protein aggregation and the gel network structure is poor.2.The formation mechanism of the MCP-WPI gel was preliminarily explored.The formation of the mixed system gel was closely related to the pH,the amount of MCP addition and the strength of calcium ion.The results showed that the molecular force between the MCP and WPI under different conditions was mainly through hydrogen bonding interaction and hydrophobic interaction,and both formed a polymer protein semi-crystalline macromolecular polymer,which is caused by T2.As the pH value increased,the surface hydrophobicity continues to increase,and the free cholesterol group gradually decreased.The reason may be that alkali treatment destroys the recombinant structure of the protein,triggers the expansion of the protein molecule structure,and causes the original thiol group embedded in the protein molecule Exposure to the surface of protein molecules.In the case of pH 4 MCP-WPI composite gel,some large aggregates can be observed.The gel formed at pH 10 has uniform and fine water pores.The overlap between the networks converts the rising MCP concentration continuously.The addition of calcium ion changed the three-dimensional network structure of whey protein isolate gel.3.MCP-WPI composite gel has good gel properties and has the potential to develop new products,so a new Mesona chinensis-containing milk jelly has been developed.Process optimization was carried out using response surface optimization test method.The results showed that the optimal process parameters of whey protein nutritional jelly obtained by response surface optimization experiments were:jelly jelly 4.99%,WPI 2.06%,sucrose 6.97%,citric acid 0.08%.The product is evaluated through sensory evaluation and texture.The product has a smooth appearance,a uniform and delicate texture,and is transparent and free of clots.The gel has good elasticity and can be restored to its original state after slight extrusion.The color is transparent,the flavor is rich,it has a light milk flavor,the taste is smooth,the sweet and sour is moderate,and the sensory score is 86 points.The jelly produced is safe and hygienic,meets national standards,has moderate hardness and elasticity,and is suitable for the sensory preferences of most people. |
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