Effect Of Lipid Types And Fatty Acid Saturation Degree On The Pork Meat Proteins Emulsifying Properties

China is the largest pork producer and consumer country in the world.The pork is blessed with high nutritional value,delicious taste and unique flavor.It becomes the ideal green nutrition food.The low-temperature emulsified meat products increasingly become one of the consumer favorite meat products.It contains 20-30 % of lipids wrapped and fixed in the protein matrix and provide the rich flavor,juicy,taste and appropriate tenderness.In this paper,pork meat batter was used as the research object.Different lipids were added in the process of chopping and different fatty acids(oleic acid,linoleic acid and linolenic acid)were added into salt-soluble protein solution.From the perspective of the mechanism,the effects of different lipids on the physical and chemical properties of emulsified meat batters,and different saturation degrees and adding amount of fatty acids on the emulsifying properties of muscle protein were studied.The competitive adsorption between lipids and salt-soluble protein was also explored.It aimed at determine the effect of lipids type on the quality of emulsified meat betters and explore the relation between protein membrane formation and protein maintain the stability of the emulsion.These could provide a theoretical basis for the application of lipids.The specific research contents and conclusions are as follows:1 Analysis of the fatty acid composition of different lipid typesThe soybean oil,backfat and butter were used as the research object.The polarity of the lipids,fatty acid content and fatty acid composition were analyzed by chemical analysis method and GC-MC method.It was analyzed from the fatty acid saturation degree and the fatty acid chain length.The results showed that butter contains more saturated fatty acids and soybean oil contains more unsaturated fatty acids and neutral lipid.While the content of medium chain fatty acids in the backfat was between soybean oil and butter samples,but the butter was significantly higher than others.In the three lipids,Oleic acid(C18:1)and linoleic acid(C18:2)content were more,linolenic acid(C18:3)content was relatively less.It indicated the polarity,fatty acid content and composition in the different fat was very different.2 Effect of lipid types on Water/Fat-binding capacity and rheological properties of emulsified meatThe different emulsified meat batters system was used as the research object.The effect ofdifferent polarity lipids on the emulsion stability,surface hydrophobicity,surface active sulfhydryl content,the particle size and the dynamic and static rheological properties and color were studied through the muscle protein emulsified The results showed that the cooking loss of soybean oil group was the least,and the backfat group was the second,so the soybean oil could improve the emulsion stability of the emulsified meat batters system.The surface hydrophobicity and surface active sulfhydryl content of soybean oil group showed a significant decrease trend.The D10 and D50 of the butter group showed the lowest value,while the D90 of the soybean oil group was significantly lower than the other two groups(P < 0.05),which indicated that it was related to the lipids state.Rheological properties indicate that the backfat group and the soybean oil group showed better viscoelasticity and butter group was poorer relatively.Comprehensive the above shows that the addition of soybean oil can improve the stability and rheological properties of emulsified meat emulsion to a certain extent.At the same time,different lipids have different effects on the microcosmic conformational changes of proteins,and the disulfide bond and hydrophobic interaction are the main chemical forces involved in the process of protein emulsification.3 Effect of lipid types on protein membrane formation in emulsified meatThe emulsion layer was used as the research object.The effects of the different lipids on the formation of protein film in the emulsion layer were studied which include emulsion stability,particle size of emulsion particles,Zeta potential,the average particle size of lipid particles and applyed the electrophoresis to trace the changes of the protein composition in emulsified layer.The results showed that the emulsifying activity of the emulsified layer showed the backfat group was larger than butter group and soybean oil group was the least.While the emulsion stability showed the butter group was lager than the back fat group and the soybean oil group was the least.The droplet size of the backfat group in the emulsion was significantly smaller.But the backfat particles obtained after the destruction of the emulsified system were significantly larger than the other two groups.The distribution of the microparticles in the emulsion was more concentrated than the distribution of the lipid particles after the destruction of the emulsified system.These indicated that the protein membrane formed in protein particles or droplet surface could effectively prevent the accumulation of lipid particles or droplets.From the Zeta potential value,the stability of the muscle protein solution was higher than the original emulsion.The absorption amount of protein(?T)on the lipid particles surface and unit interface membrane absorption amount of protein(?s)in the butter group were higher than that in the other two groups.In short,the muscle protein could better emulsified backfat to improve the emulsifying activity and emulsified butter to the increase emulsion stability of the emulsion.And after emulsification system damaged,butter could increase ?T and ?s.So butter can effectively formprotein film,this is helpful to improve the stability of emulsion.4 Effect of fatty acid saturation degree and adding amount on muscle protein emulsifying properties.The salt-soluble protein was extracted,and the composite emulsion was prepared by adding oleic acid,linoleic acid and linolenic acid.The composite emulsion was analyzed.The effects of different saturation degrees and adding amount of fatty acids on the emulsifying properties,rheological properties and Zeta potential were studied.The results showed that the larger the amount of fatty acid,the stronger the emulsifying activity of the emulsion was.Under the same adding amount,the fatty acids of different saturation degree play a better role in the emulsification.While addition amount could resulted more serious the stratification of the emulsion,which maybe due to the fact that the greater the amount of the emulsion,the more likely to the emulsion was happen accumulate and bridge.Oleic acid and linoleic acid could significantly increase the surface active sulphur the emulsion.The emulsion particle size distribution curve showed single peak type and moved left.With the increase of shear rate,the viscosity of the emulsion decreased gradually and finally became gentle.Under the same shear rate,the greater the adding amount,the greater the shear stress was.From the Zeta potential value,the stability of the emulsion was relatively unstable.In general,fatty acids(C18)with different additions and different saturation degree have different effects on the pork salt soluble protein,and in further affect the emulsifying properties,microstructure and Zeta potential properties of emulsions.