Effects Of Fats On The Stability Of Myofibrillar Protein Emulsions And Gel Properties Of Meat Batters

Zeta-potential,particle size,rheological properties and microstructure were carried out to evaluate the effect of fats on stabilities and protein conformations of emulsification system of myofibrillar protein combined with Raman spectroscopy and interfacial protein adsorption.The correlation between emulsion stability and protein secondary structure was established.Color,centrifugation loss,texture and rheological properties were carried out to evaluate the effect of myofibrillar protein emulsions on water-holding and texture properties of emulsified gel.And the relationship between protein conformation and stability of emulsions was established.Then the stability mechanism of the myofibrillar protein emulsion system was investigated.Therefore,it provides a theoretical basis for the development of new low-fat meat products.The main findings are as follows:1 The emulsion is formed from myofibrillar protein emulsified butter/soybean oil/lard.The effects of emulsifying activity,emulsifying stability,Zeta-potential,particle size distribution and rheological properties on the stability of the emulsions were examined.The particle size of the emulsion decreased with the increase of fat addition?1%,3%and 5%?,and the emulsifying activity and the absolute value of Zeta-potential increased.The soybean oil groups D10,D50 and D90 correspond to the smallest particle size,while the emulsifying activity and Zeta-potential are significantly higher than those in the butter and lard treatment groups.When the amount of fat added was the same,the ESI difference?6.53?of the soybean oil group was the smallest in 120 min,and the butter group?106.50?was the largest.Therefore,compared with butter and lard,soybean oil can interact well with myofibrillar protein,and the formed emulsion has better stability.2 The emulsion layer of myofibrillar protein emulsion was extracted and tested for protein adsorption,Zeta-potential and Raman spectroscopy.The effect of butter/soybean oil/lard on the conformational changes of myofibrillar protein was investigated from a microscopic view.The results showed that the absolute value of Zeta-potential was the highest in the soybean oil group?100.07 mV?,the second in the butter group?65.93 mV?,and the smallest in the lard group?59.77 mV?.The amount of protein absorbed in the interface between the butter group,the soybean oil group and the lard group??s?were 151.34,111.30,and 37.13 mg/m²,respectively.The?-helix content?63%?of the soybean oil group was lower than that of the butter group?75%?and the lard group?69%?,while the?-sheet content?13%?was the largest.Correlation analysis showed that?-helix content was positively correlated with?s and d_3,2,while?-sheet,?-turn and random coil were negatively correlated with?s and d_3,2.Therefore,when?s or d_3,2,2 are larger,the?-helix content is higher,which indicated the degree of protein molecule expansion is lowered.3 The meat batters containing different proportions of myofibrillar protein emulsion were tested for color?before and after cooking?,centrifugal loss rate,texture and rheological properties.The effect of myofibrillar protein pre-emulsions on the water-holding capacities and texture properties of the meat emulsion gel matrix was investigated.The redness?a*?value and the yellowness?b*?value of meat batters were reduced by heat treatment.When the fat content of the emulsified gel is lowered,the redness and centrifugation loss of meat batters gel is increased,the overall color is deepened,and the hardness,gumminess and chewiness are decreased.Both shear stress and viscosity decreased with increasing proportion of myofibrillar protein pre-emulsions.Correlation analysis showed that hardness,adhesion,chewiness and centrifugal loss rate?R=-0.350,R=-0.495,R=-0.449,P<0.05?showed a significant negative correlation,centrifugal loss rate and emulsified meat D50,D90?R=0.556,R=0.431,P<0.01?showed a very significant positive correlation.Therefore,when the particle size of the emulsified meat emulsion particles is small,the centrifugal loss rate of the emulsion gel is lower.As the water retention of the gel decreases,the hardness,gumminess,and chewiness of the emulsified gel decrease.