Study On The Processing And Nutritional Properties Of Myofibrillar Protein-silkworm Pupa Protein Binary Protein System

In order to introduce insect protein into the food system and become a sustainable substitute for some poultry and livestock proteins,while improving the utilization rate and high value of insect protein.In this paper,myofibrillar protein(MP)and silkworm pupa protein(SW)were taken as the research objects,and the effects of added amount of SW on MP-SW binary protein conformation,emulsifying properties and changing laws of viscoelasticity were revealed by gel electrophoresis,Raman spectroscopy and rheological techniques.A system of ultrasonically modified binary protein aggregates was established,and the effect of high-intensity ultrasonic treatment on aggregates was clarified by measuring the secondary structure and tertiary structure of binary protein aggregates combined with the microstructure and emulsification characteristics of the binary protein aggregate emulsion;Finally,the effects of high-intensity sonication on the amino acid composition,antioxidant activity and in vitro digestion of myofibrillar protein-silkworm chrysalis protein aggregates were determined.Thus,it provides a theoretical basis for constructing a stable binary protein system and producing novel binary protein functional products.The main findings are as follows:1.The protein composition,emulsifying properties,protein conformation and rheological properties of the different ratio MP-SW binary proteins were determined.The results showed that with the increase of SW,the type of protein decreased,and the emulsion stability gradually decreased.With the proportion of SW increased,the hydrophobicity of the binary protein was significantly enhanced(P < 0.05).The reduction of α-helix structure and the increase of β-sheet structure in the emulsification process.The G’ decreased and the tanδ increased,at the same time,the viscosity of the binary protein emulsion decreased with the increase of the proportion of SW.2.The protein composition,surface charge,particle size and protein conformation of the ultrasonic treatment of MP-SW(UM),MP-ultrasonic treatment of SW(US)and the Simultaneous ultrasonic treatment of MP-SW(UMS)binary protein aggregates were determined.And the emulsion surface charge,aggregate size,microstructure and emulsifying properties of four binary protein aggregates were evaluated.The results showed that the cavitation effect of ultrasound reduced the particle size and enhanced the surface electrostatic interaction of binary protein aggregates;the content of α-helix was significantly decreased,while the content of β-sheet and β-turn was significantly increased(P < 0.05);After ultrasound treatment of MP-SW binary protein aggregates,the surface hydrophobicity was significantly increased(P < 0.05),the total thiol content was significantly decreased(P < 0.05),the disulfide bond content was increased and the fluorescence intensity was decreased,indicating that the exposure of hydrophobic groups and the sulfhydryl to disulfide bonds.Ultrasonic modification of binary protein aggregates improves their microstructure and improves the emulsion stability of emulsions.3.The nutritional properties of MS,UM,US,UMS were evaluated by amino acid analysis,nutritional evaluation,antioxidant activity and in vitro digestion process.The results showed that the ratio of essential amino acids/total amino acids of the modified binary protein aggregates was higher than the recommended model of the United Nations Food and Agriculture Organization/World Health Organization(FAO/WHO),amino acid score(AAS)and essential amino acid index(EAAI)were significantly improved(P < 0.05).The DPPH clearance and total reducibility were significantly improved in the treatment group(P < 0.05),and CLSM combined with particle size and Zeta-potential demonstrated that ultrasound treatment improved the digestibility of binary protein aggregates.