Effects Of Physical Processing On The Interaction Of Gliadin-Rutin Complex And The Properties Of Emulsion Stabilized By The Complex

In view of the mixed use of buckwheat and wheat in daily life and the emergence of multi-grain products,the interaction between gliadin(g)and rutin(R)is inevitable.Processing conditions are a vital part of the food production and processing.Temperature,dynamic high-pressure microfluidization(DHPM)and ultrasound have important effects on the physical and chemical properties of proteins.Moreover,the interaction between proteins and other substances is inevitably affected by the above conditions.Therefore,this study explored the influences of temperature,DHPM and ultrasonic power on the interaction mechanism of gliadin(G)and rutin(R),and complex structure and functional characteristics of G-R were determined.The research provided theoretical basis and guidance for developing high protein foods rich in bioactive substances.The key study contents and results are summarized as follows:(1)The complex of gliadin and rutin(mass ratio 10:1)was prepared by antisolvent method and then heated at 25?,60?,80?,100? for 30 min.The interaction mechanism between wheat gliadin and rutin was investigated by fluorescence spectrum,ultraviolet visible spectroscopy,fourier transform infrared spectroscopy and Raman spectra.The particle size,potential,surface hydrophobicity,thermal stability and microstructure of the samples were determined.The results revealed that the quenching mechanism of G by R was dynamic and static at all temperatures.After compounding with rutin,the secondary as well as tertiary structure around the protein fluorophore changed,and the microenvironment changed.The content of gauche-gauche-trans conformation decreased,while the content of tauche-gauche-tauche conformation increased.Thermal induction led to the occurrence of aggregation,the reduced thermal stability,the denser network structure and the increased pores.(2)The Pickering emulsion was prepared by homogeneous emulsification with the oil(soybean oil)/water ratio was 5:9(v/v).The formation and properties of the emulsion were studied.The result showed that G-R treated by 80? stabilized-emulsion had higher viscosity and stronger gel property.The emulsifying activity and emulsion stability were higher than those of the other samples.The continuous network structure of the protein particles in the continuous phase stabilized the emulsion as 80?.(3)The surface hydrophobicity,particle size,potential and free sulfhydryl groups of the complex were measured after being treated by DHPM(0 MPa,40 MPa,80 MPa,120 MPa,160 MPa,twice).The effects of R combined with DHPM on the structure and physicochemical properties of G were studied by FTIR,raman spectroscopy,scanning electron microscopy and differential scanning calorimetry.R changed the microenvironment of tryptophan and tyrosine,and led to the rearrangement of protein secondary structure.With the increase of pressure,the content of gauche-gauche-gauche and trans-gauche-trans conformation increased,the content of gauche-gauche-tauche conformation decreased,the particle size decreased markedly,the content of free sulfhydryl group and surface hydrophobicity increased,and the thermal stability improved.(4)Pickering emulsion was prepared by homogeneous emulsification with the oil(soybean oil)/water ratio was 1:1(v/v),and the formation and properties of the emulsion were studied.The emulsion stabilized by G,which treated by 120 MPa after loading rutin,had higher viscosity and stronger gel property,and the potential of the emulsion were higher than that of the other samples.Under this condition,the formed-emulsion was more stable,and more the protein particles in the continuous phase were adsorbed on the surface of the oil droplet.(5)After ultrasonic treatment(0 W,150 W,300 W,450 W,600 W,20 min),the structure and functional properties of G were studied by multi-spectral technology and a variety of physical and chemical indexes.At low ultrasound power,the particle size gradually decreases,the potential and surface hydrophobicity had no significant effect,but the solubility increased.Ultrasonic treatment exposed protein structure,changed the microenvironment of tryptophan and tyrosine residues,and led to the rearrangement of secondary structure of gliadin.After ultrasonic treatment,the honeycomb was uniform and dense.The interfacial tension of G-R decreases more obviously.(6)Pickering emulsion was prepared by homogeneous emulsification with the oil(soybean oil)/water ratio was 3:5(v/v),and the formation and properties of the emulsion were studied.After ultrasound,the absolute zeta potential values of all the emulsions stabilized by the complex were significantly increased,and the electronegativity was greater.Ultrasonic treatment can enhance the interaction between G and R,improve the stability and gel properties of emulsion.The emulsion stabilized by G,which treated by450 W after loading rutin,had higher viscosity and stronger gel property,and the emulsifying potential is higher than that of other samples.