Effect Of Dynamic High Pressure Microfluidization On Properties And Structures Of Wheat Gluten

Application of dynamic high pressure microfluidization technology for modification ofwheat gluten provided an important theoretical basis to widen the industrial application ofwheat gluten and dynamic high pressure microfluidization. Influence of dynamic highpressure microfluidization on the functional properties of wheat gluten in distilled water anddifferent pH solution was studied. The mechanism of the influences of dynamic high pressuremicrofluidization on wheat gluten was discussed through the changes in molecular structure.Meanwhile, explored the application of wheat gluten treated by dynamic high pressuremicrofluidization through measuring the rheological properties of wheat gluten.The mainresults are as follows:1. Effect of microfluidization on functional properties of wheat gluten in distilled waterwas studied. Choose the concentration of wheat gluten:2%,4%and6%, and the pressure ofmicrofluidization:0.1MPa,40MPa,60MPa,80MPa and100MPa.The results showed thatmicrofluidization treatment could increase the solubility of wheat gluten in distilled water, butthe effect has something to do with the protein concentrate. The best concentreatino wasdetermined as4%, and in this concentration, whey gluten reached its highest solubility4.81,which was24%higher than that of control, after80MPa microfluidization. The influence ofmicrofluidization on foaming and emulsifying properties of wheat gluten was also associatedwith protein concentration.When the concentration was4%, with the increase of pressure,foaming ability remained constant followed by decreasing, and foam stability, emulsifyability and stability increased, reaching the maximum at100MPa, which was100%,0.744and0.553, respectively, and13.8%,17.4%and64.6%better than control. When theconcentration was2%or6%, with the increase of pressure, foaming ability increased,reaching the maximum at100MPa, which was136%and140%, respectively, and13.3%and33.3%better than control; and foam stability, emulsify ability and stability decreased. DSCanalysis indicated that high molecular weight subunit was destroyed and some newaggregation was formed, which changed the functional propertied of gluten protein.2. Effect of microfluidization on functional properties of wheat gluten in different pHsolution was studied. Dissolved the wheat gluten in pH2~5, making the concentration4%,and then treated by microfluidization at pressures of0.1MPa,40MPa,60MPa,80MPa and100MPa. Results showed that microfluidization treatment could not improve the solubility ofwheat gluten dissolved in pH2~5solution, but even decreased the solubility. DSC analysisindicated that microfluidization treatment could not change the molecules structure of wheat gluten in pH2solution, but caused gathering, resulting in a decreased solubility.3. Effect of microfluidization on structure of wheat gluten was studied by measuring theparticle size, SDS-PAGE, surface hydrophobicity, UV absorption spectra and circulardichroism changes of wheat gluten in water or pH=2solution treated by100MPamicrofluidization. Results showed that after microfluidization at100MPa, the particle sizedecreased. SDS-PAGE indicated that for wheat gluten in distilled water, small moleculeaggregation increased and large molecular weight subunits was destroyed, leading to moresmall molecular weight subunits, which improved solubility. As for wheat gluten in pH=2solution, macromolecular micelles increased, which decreased solubility, but did not changethe structure of wheat gluten protein. Microfluidization could make wheat gluten proteinmolecules stretch and surface hydrophobicity index increase; while fluorescence spectrum,ultraviolet spectrum and circular dichroism showed that microfluidization treatment did notchange the secondary and tertiary structure of wheat gluten.4. Effect of microfluidization on rheological properties of wheat gluten was also studied.Viscosity and wet gluten protein frequency and temperature sweep was measured. Resultsshowed that after100MPa microfluidization, apparent viscosity of wheat gluten increased indistilled water, but decreased in pH=2solution, and it’s the same case for the elasticity of wetgluten. The phenomenon was caused by molecules aggregate stability. At lower temperature,100MPa microfluidization treatment could increased the storage modulus and loss modulus ofwet gluten in distilled water, but in pH=2solution, the opposite result was obtained. At highertemperature, the situation was at the opposite of that at lower temperature, which showed thatthe aggregation caused by microfluidization was unstable.