Study On Ultrasonic Modification Of Tenebrio Molitor Protein And Preparation Of Oil-in-water Emulsion

Tenebrio molitor,as a common insect in nature,has the advantages of rich protein content and easy large-scale farming.It is an excellent feed and food raw material.However,Tenebrio Molitor Protein is mostly used in the field of animal feed,and there is a lack of technology for high-value utilization of food,resulting in not being widely used in the food industry.At present,emulsions are widely used in the field of food,with functions such as improving the state of food and delivering fat-soluble active ingredients.Using natural protein as an emulsifier to prepare emulsion not only has a wide range of sources,excellent stabilization effect,but also is safer and beneficial to the application in the food industry.In this paper,using Tenebrio molitor as natural protein raw material,water-soluble Tenebrio Molitor Protein(TMP)was prepared by alkaline precipitation and acid extraction,and the physicochemical properties of TMP were studied.On this basis,an oil-in-water emulsion was developed using this protein.Ultrasonic Tenebrio Molitor Protein(UTMP)was prepared by ultrasonic modification of TMP,and characterized by fluorescence spectroscopy,surface hydrophobicity(H₀),scanning electron microscopy(SEM),particle size,UV spectroscopy,free sulfhydryl content,and XRD.In order to broaden the application scope of Tenebrio molitor and TMP,and provide technical basis for their application in food industry.The main contents and results of this study are as follows:(1)Extraction and characterization of water-soluble Tenebrio Molitor Protein(TMP).The protein morphology and size,zeta potential,wettability,and interfacial tension were characterized.The wettability shows that the three-phase contact angle of TMP is closer to 90°(?=97.0°)and has natural amphiphilicity.The results of Zeta potential value show that the isoelectric point of the solid is around 4.(2)Study on the effect of TMP stabilizing emulsion.Through the stabilization effect of emulsions in different storage environments.Using droplet morphology and emulsification index,the effects of p H,particle addition,temperature,and oil phase fraction on the effect of TMP-stabilized emulsions were studied,and the rheological properties of TMP-stabilized emulsions were analyzed.It is found that the emulsion can exist stably in harsh environments(high temperature,strong acid,strong alkali)and low particle concentration(0.5%).And when the protein concentration was 2.0%,the emulsion exhibited the most beneficial emulsifying properties.When the oil phase fraction reaches 80%,the emulsion can be stored stably for 30days at room temperature,indicating that it can prepare a stable high inward emulsion.The rheological behavior showed that all emulsions were pseudoplastic fluids,and the viscosity and shear resistance of the emulsions showed a significant positive correlation with protein concentration and oil phase volume.(3)The effect of ultrasound on the properties of TMP and the application of emulsion stability.The UTMP was obtained by ultrasonic treatment of the TMP prepared in the previous stage.Sonication separated the soluble aggregates in TMP,and the particle size of TMP was significantly reduced from 818.3±20.1 nm to 318.5±17.1 nm.Through experiments such as UV spectroscopy and fluorescence spectroscopy,it was found that ultrasound can change the secondary and tertiary structures of TMP,and at the same time lead to an increase in protein hydrophobicity and free sulfhydryl content.Changes in protein structure properties have different promotion effects on the functional properties(solubility,WHC,OHC,foamability,foam stability,emulsification,etc.)of TMP.Especially for foaming and foaming stability,the amount of protein foam and the stabilization time are effectively improved.Subsequently,UTMPEs were prepared by UTMP and characterized by particle size analysis,microstructure,and rheological behavior.The results show that the particle size of the TMP stabilized emulsion after ultrasonic treatment is smaller,the stabilization effect is better,the interface adsorption protein is more,and the emulsion structure is more compact.