Study On Emulsifying And Processing Properties Of Myofibrillar Protein And Chicken Plasma Protein

In recent years,with the improvement of people's living standard and the enhancement of health consciousness,reduced-fat meat products have got more and more attention from consumers.Many researchers have studied reduced-fat foods.In order not to change the product quality,fat substitutes are appearing.Fat substitutes are important additives in food processing.Pre-emulsions as a replacement of animal fat have become a hot topic among the world researchers.Pre-emulsion is composed of fat,protein and water and it has good water-and fat-binding properties,stable physicochemical properties and more conducive to keep the mince emulsify material stability,etc.Pre-emulsions have been used in the fermented sausage and Frankfurt sausage,so as to achieve lower fat content and change the fatty acid composition of meat products.The emulsion stability is affected by the pH and sodium concentration,and also some studies have shown that the protein of pre-emulsions is likely to do competitive adsorption in the fat surface with the myofibril protein,which may cause the composition and stability of the emulsion system changing.So,in this paper,firstly,the effect of different pH and sodium concentration on emulsion stability and secondary structure of myofibril protein and chicken plasma protein have been studied.Secondly,the competitive adsorption in fat surface of emulsion between chicken plasma protein and myofibril protein have been studied.Finally,we studied the effect of soybean oil emulsified and un-emulsified with chicken plasma protein on the physicochemical properties of reduced-fat frankfurters.The contents and results were as follows:1?Effect of different pH and sodium concentration on emulsion stability and secondary structure of myofibril protein and chicken plasma proteinWith the pH and sodium concentration increasing,the emulsifying viscosity of myofibril protein increased,it was highest when the pH was 6.5 or 7.0 and sodium concentration was 0.6mol/L,and also had better emulsifying stability,lower surface hydrophobicity and a-helix content,higher ?-sheet content.Different sodium concentrations have no obvious influence on chicken plasma protein.With the pH increasing,the emulsifying viscosity and ?-sheet content of chichen blood plasma obviously increased(P<0.05),surface hydrophobicity and ?-helix content decreased(P<0.05).When pH was 7.0,chicken plasma protein had higest emulsifying viscosity and[-sheet content,lowest surface hydrophobicity and a-helix content and the emulsifying stability was better(P<0.05).2.Study on the competitive adsorption emulsion between chicken plasma protein and myofibril proteinResearch the effect of different emulsifying order on the competitive adsorption emulsifying between chicken plasma protein and myofibril protein found that chicken plasma protein,vegetable oil and water was emulsified firstly,and then emulsified with myofibril protein,the emulsion had better emulsifying stability,emulsifying activity,its viscosity value is also highest,the particle size of emulsion was smaller.By comparing the emulsion interface adsorption of protein composition and content found that chicken plasma protein and myofibril protein had competitive adsorption in the surface of the fat.3?Effect of soybean oil emulsified and un-emulsified with chicken plasma protein on the physicochemical properties of reduced-fat frankfurtersThe effects of reduced pork back-fat levels from 30%to 20%,15%and 10%with addition of chicken plasma protein(CPP)as a powder additive or as a emulsifier in pre-emulsified soybean oil(SO)on the physicochemical properties,texture and microstructure of frankfurters were investigated.Reduced-fat frankfurters containing CPP had low energy contents and apparent viscosity,showed good emulsion stability compared with the control with 30%fat.With increasing substitution of pork back-fat,frankfurters containing CPP showed higher protein and ash contents(P<0.05),were more yellow and lighter in color,had increased weight loss by pressing,higher springiness and cohesiveness(P<0.05),while the hardness of frankfurters became lower(P<0.05).Utilize CPP as a stabilizer in pre-emulsified soybean oil was beneficial for water hold capacity,texture profile analysis,emulsion stability,apparent viscosity(P<0.05)and gave a homogeneous distribution of fat globules in frankfurters compared to those where CPP was added as a powder additive.