Study Of The High Pressure Microfluidization On Modification Of Soy Protein Isolate

In view of this fact that there are few researches on the application of ultra-high pressure micro-fluidization in the modification of protein, and that the in-depth studies on the functional property changes are still lacking both at home and abroad, this paper focuses on the modification of soy protein isolate treated by high pressure microfluidization. This paper offers a new approach to protein modification as well as a new method on the application of dynamic high pressure microfluidization, and provide a new way for the further utilization of protein resources. The experimental results of this paper are summarized showed as follows:1. Solubility are changed by dynamic ultra-high pressure micro-fluidization: the solubility of soy protein isolate increase with the microfluidization pressure; microfluidization times can not further improve the solubility of soy protein isolate; as to soy protein isolate of different concentrations, lower concentration's solubility go up more notably; the lower temperature is more conducive to the improvement of the solubility.2. Emulsifying are changed by dynamic ultra-high pressure micro-fluidization: the emulsifying properties of lower concentration soy protein isolate (2%) increase with the microfluidization pressure range from 20MPa to 100MPa and as the pressure increased further, emulsifying properties decreased; the emulsifying properties of the higher concentration(4%, 6%, 8%) after treated by dynamic high pressure microfluidization are decreased. With the increase of the microfluidization times, emulsifying properties and emulsifying stability of soy protein isolate both decreased. The temperature affected emulsifying properties and stability with no change.3. Foaming property are changed by dynamic ultra-high pressure micro-fluidization: the foaming property of soy protein isolate is better with the increase of the pressure and the foaming property of the higher concentration soy protein isolate excelle lower concentration's and foaming property change little by microfluidization times and microfluidization pressure. 4. Gelation are changed by dynamic ultra-high pressure micro-fluidization: the gelation of soy protein isolate increase with the microfluidization pressure and we can gain better sensory-quality gel.5. Viscosity are changed by dynamic ultra-high pressure micro-fluidization: after soy protein isolate treated by the dynamic high pressure microfluidization, fluid show shear thinning and close to Newtonian fluid, microfluidization's times do not result in great changes for rheological property and they all showe close to Newtonian fluid. The viscosity improve with the increase of soy protein isolate concentration. The temperature had little impact of viscosity.6. Film tensile strength and elongation are changed by dynamic ultra-high pressure micro-fluidization: soy protein isolate's film tensile strength enhance at first, achieve the maximum at 100MPa and then decrease with the increase of the microfluidization pressure. The optimum tensile strength and elongation appeare at 100MPa, soy protein isolate have great potential to become edible film at this pressure.7. Paiticle size and functional groups are changed by dynamic ultra-high pressure micro-fluidization: after soy protein isolate treated by the dynamic high pressure microfluidization, the average particle size reduce greatly, but changed little with the increase of microfluidization pressure, the minimum average particle size is at 140MPa, which is 167.5nm; the content of-SH increase with the pressure, after a little decrease at 100MPa, go on increasing until 160MPa; after soy protein isolate treated by the dynamic high pressure microfluidization, relative fluorescence intensity reache the maximum when the pressure go up to 100MPa; and UV maximum of absorbing wavelength is blue shift, the UV maximum of absorbing intensity increase with the pressure, reache the highest 3.562 at 80MPa, then decrease gradually, a little increase at 160MPa; the DSC curve's peak move rightward, peak temperature is higher than that of the untreated soy protein isolate.