Effect Of System Conditions And Ultrasonictreatment On Pre-emulsion Soybean Oil

Emulsified sausages and minced meat products such as meatballs and luncheon meats have become more and more important in meat products and have become an important part of people's daily dietary consumption.During the processing of meat emulsion products such as emulsified sausages,exogenous oils and fats can be added to the meat emulsion,whether it is to enhance flavor or to replace animal fat to reduce cholesterol content.However,the accompanying technical problems also affect the quality of the product,such as the sausages are easy to produce oil and water during the cooking process,the final product has poor structural organization and poor elasticity.In recent years,the method of pre-emulsification has been gradually applied to this field,that is,the oil,protein,and water are firstly formulated into a pre-emulsion,and then it is mixed with the meat emulsion.The effect of pre-emulsification will affect the oil retention of minced meat products.Increasing the pre-emulsification effect can increase the emulsification effect of the whole minced meat,thereby improving the oil retention of the minced meat.The pre-emulsification effect is related to the conditions and methods of pre-emulsification.The optimization of the system conditions and supplementary measures may increase the adsorption amount of protein on the surface of the added oil particles and the stability of the binding.At present,there are relatively few studies on the stability and applicability of fat pre-emulsions in China.Therefore,this topic studied the effects and mechanisms of different system conditions(protein addition amount,lipid-water ratio,pH,and NaCl concentration)on the effect of pre-emulsions At the same time,the ultrasonic method was used to assist in the preparation of the pre-emulsion,and finally the pre-emulsion-myofibrillar composite gel was prepared to verify the oil and water retention and texture characteristics of the gel.Production provides theoretical basis and technical reference.The main findings are as follows:1.Pre-emulsions were prepared with sodium caseinate,soybean oil and purified water as raw materials.Within the range of 0.1%to 0.5%of protein addition,with the increase of protein addition,the emulsification activity and emulsification stability of the pre-emulsion showed a significant upward trend;the emulsion stratification index gradually decreased,and the protein addition amount was 0.5%The pre-emulsion did not delaminate obviously after being left for 24 hours.The increase of protein addition significantly increased the viscosity of the emulsion and the adsorption of interfacial proteins.The average particle size of the droplets decreased from about 60?m to 7.28?m,and the particle size distribution range Narrower,the emulsion is more uniform and stable.2.In the range of 1:2?2:1,the emulsification activity of the pre-emulsion increases gradually with the increase of the proportion of oil phase volume,and the emulsification stability and emulsion delamination also gradually improve;When the ratio is greater than 1:1,the viscosity of the emulsion is about 5 times higher than that of the other groups.It is found from the microstructure diagram that this is related to the close-packing of the droplets.The adsorption amount of interfacial proteins showed an upward trend;when the lipid-water ratio was less than 1:1,there was no significant difference in the average droplet size and distribution range of milk droplets,and then it decreased and then increased.3.The emulsion's pH environment is in the range of 3?11.When the pH is 3 and5,the emulsification activity of the pre-emulsion decreases significantly.The emulsion is severely delaminated after 6 hours of storage.The reasons for this are its lower emulsion viscosity,zeta-potential absolute value,and interface protein adsorption.The concentration of milk droplets was serious at pH 3,and the average particle size and distribution range were much higher than those of other groups.Taken together,the pre-emulsions have higher stability at pH 7 and 9.4.When NaCl was added to the pre-emulsion at a concentration of 0 to 0.84mol/L,compared with the control group,the emulsification activity of the pre-emulsion with NaCl was significantly reduced;except for the 0.06 mol/L sample group,the emulsification stability of the other groups was 120 min.Are lower than the control group;the addition of NaCl can significantly increase the viscosity of the emulsion and the amount of interfacial protein adsorption;the absolute value of the zeta-potential of the emulsion is smaller than that of the control group when the concentration of NaCl is?0.36 mol/L,and its microstructure shows that milk droplets occur to a certain extent When the flocculation and the NaCl concentration was 0.84mol/L,larger droplets appeared in the droplets,making the average diameter larger than that of the control group.5.With the increase of ultrasonic power,the emulsification activity of the emulsion first increased and then decreased,and reached a maximum of 59.95 m~2/g at360W,and the emulsion of each ultrasonic treatment group did not delaminate within36h.With the increase of ultrasonic power,the initial viscosity of the pre-emulsion increased significantly,and the average droplet size decreased directly from micrometer to nanometer,and the particle size distribution range became narrower.When the ultrasonic power is 360W and 480W,the adsorption amount of the emulsion interface protein reaches the maximum value,and the protein utilization rate is greatly improved.The measurement results of Raman spectroscopy show that with the increase of ultrasonic power,the?-helical structure contained in the emulsion may be more and more transformed into random curl,and the increase in flexibility is favorable for its adsorption at the oil-water interface.At the same time,changes in the structure of the protein also led to changes in zeta-potential,the net charge decreased,and stabilized after the power reached 360W.In general,ultrasonic treatment can significantly improve the effect of soybean oil pre-emulsion and its stability.6.The oil and water retention and texture properties of three different pre-emulsion systems and fish myofibrillar protein after forming a composite gel are compared.The results show that the pre-emulsions after ultrasonic treatment and adjustment of the system pH and ionic environment,the The formed composite gel has better oil and water retention characteristics than the other two groups,and the cooking loss rate is also significantly reduced from 16.34%to 8.18%.Compared with the protein gel prepared without the pre-emulsification step,its hardness,Elasticity,chewability,etc.have been significantly improved.