Study On The Properties Of Guar Gum And Xanthan Gum Emulsions And Their Effects On Myofibril Protein Emulsification And Gel Properties

Emulsion-type meat products are favored by more and more consumers because of their unique flavor and rich nutrition.Proteins and fats are the main components of emulsion-type meat products.Fats are often emulsified and encapsulated by proteins,and then presented in protein gel systems.With the same as other emulsions stabled by proteins,emulsion-type meat systems are also unstable.A series of problems such as water outflow,oil outflow,and structural looseness occur from time to time,and ultimately lead to the deterioration of product texture and degradation of functional properties.Therefore,it is necessary to find a suitable method to stabilize the protein emulsion and at the same time improve the quality of meat products.As a natural biological macromolecule,polysaccharides have many important functional properties and have been widely used in the food industry.In recent years,polysaccharides have often been used as thickeners in meat products.Many experimental studies have also shown that polysaccharides can interact with proteins to improve the functional properties of proteins.There are deep deficiencies in the study of the interactions between pork myofibrillar protein and polysaccharide.In the present work,two different polysaccharides(guar and xanthan gum)and pork myofibrillar protein were selected as the research object,the mechanism of stabilization of pork myofibrillar protein emulsion by guar gum and xanthan gum and the effect of emulsion on protein gel were mainly studied.First,we compared two emulsions prepared with myofibrillar protein and polysaccharide solution as emulsifier.The result showed that there was a positive correlation between the storage stability,apparent viscosity and the concentration of guar gum and xanthan gum emulsion.Under high-concentration system,the stability and viscosity of guar gum and xanthan gum emulsion were higher than that of myofibrillar protein emulsion.As the increasing of the concentration,fat particles gradually became finer,and large fat particles tend to become smaller and smaller.At the same time,0.5%guar gum and 0.3%xanthan gum emulsion system as well as myofibrillar protein system showed shear rheological rheological properties.High concentration polysaccharide emulsion system showed high elastic modulus than the viscous modulus,indicating that there was viscoelastic behavior of the weak gel in both emulsion systems.Then,we studied the effect of guar gum and xanthan gum emulsion on the properties of myofibrillar gel based on the previous chapter.The results showed that the addition of guar gum and xanthan gum emulsion can significantly improve the water holding capacity of the gel,and the LF-NMR results also showed a significant reduction in free water content,indicating that the addition of polysaccharide emulsion allowed more water to be retained in the gel network.The increasing in gel texture also indicated that the addition of the emulsion improved the network structure of the protein gel.However,the results of Raman spectroscopy showed that the change of the concentration of the emulsion had no significant effect on the secondary structure of myofibrillar protein.With the addition of the polysaccharide emulsion,the elastic modulus of the composite sol system tended to increase.However,the guar gum and the xanthan gum took precedence over protein deployment and delayed the thermal denaturation of myofibrillar proteins during heating.Finally,the effects of polysaccharide type(guar gum and xanthan gum)and concentration on emulsifying and stability of myofibrillar protein emulsion were studied.The results showed that the emulsification activity and stability of myofibrillar protein emulsions increased firstly and then decreased with the addition of guar gum and xanthan gum concentration.The particle size distribution experiment found that the higher the concentration of guar gum and xanthan gum,the smaller the number of large droplets of the emulsion and the larger the number of small droplets,the emulsion system tends to be more stable.The particle size results showed that the particle size of D(x)10,D(x)50 and D(x)90 in the emulsion decreased significantly(P<0.05).However,the microstructure showed that when the concentration of guar gum and xanthan gum exceeds 0.25%,the emulsion system tended to flocculate.The ?-potential experiment results showed that the anionic polysaccharide xanthan gum can significantly reduce the ?-potential of the myofibrillar protein emulsion,while the neutral polysaccharide guar gum had no effect on the ?-potential of the myofibrillar protein emulsion.In addition,guar gum and xanthan gum can interact with myofibrillar protein.Guar gum and xanthan gum can increase the elastic modulus of the protein emulsion system and change the rheological properties.However,the interface is still dominated by myofibrillar proteins,and guar gum and xanthan gum can accumulate on the surface,reducing the interfacial tension.