Effect Of Ultrafine Comminution On Function Of Soybean Protein Isolate

This paper focused on the functional properties of soy protein isolate treated by six kinds ofultrafine comminution. This paper offered a new approach to protein modification as well as anew method on the application of ultrafine comminution，and provided a new way for thefurther utilization of protein resources. The experimental results of this paper weresummarized shown as follows:1.The effect of ultrafine comminution on functional properties of soybean protein isolate.The results demonstrated that: as crush air increased, crush time extended, particle sizereduced, its tight organization structure was loose, the specific surface area, pore surfaceenergy and porosity rate improved; with mechanical function, the contact area, contact placebetween particles and water, oil increased, and the dispersion increased, so the water-holding,oil-holding increased significantly. As particle size reduced, foaming ability, foam stability,emulsifying ability, gelation, solubility, dispersion increased, but viscosity decreased.Ultrafine comminution could affect the functional properties of SPI effectively.2.The effect of ultrafine comminution on hydrolysate of soybean protein isolate. Thedegree of hydrolysis of soybean protein isolate was not significantly different before or afterultrafine comminution.3. The effect of ultrafine comminution on liquidity of soy protein isolate. As particle sizeof soybean protein isolate reduced, the sliding angle of powder increased, which showed thatits liquidity decreases.4. The effect of ultrafine comminution on content of thiol of soybean protein isolate. Asparticle size reduced, content of thiol of soybean protein isolate rose. The reason for this wasthat ultrafine comminution caused it modified and stretch, and thiol in protein exposed.5. The effects of ultrafine comminution on DSC of soy protein isolate. Compared to theoriginal of soy protein isolate, the peak temperature of soy protein isolate after ultrafinecomminution rose, and enthalpy showed a downward trend. All the modified enthalpy ofsoybean protein isolate processed by ultrafine comminution had dropped, which indicated thatthe protein had stretched for a certain degree.6. The effects of ultrafine comminution on particle sizes and microstructure of soy protein isolate. The original sample of soy protein isolate and powders of different particle sizes weredetermined by laser particle size analyzer. Analysis showed that as crush air increased, crushtime extended, median diameter, volume average diameter, and surface mean diameter of soyprotein isolate reduced gradually, but surface area increased.