Abstract:Phytosterol (PS) has many excellent physiological activities, but the application of phytosterol in food industry is widely restricted due to low solubility and bioaccessibility. To provide a water-soluble phytosterol, okara protein (OP) was used as raw material to prepare phytosterol nanoparticles by anti-solvent method combined with dynamic high-pressure microfluidization, and physicochemical property were characterized. Dynamic high-pressure microfluidization can significantly reduce the size of OP-PS particles, and significantly improve the encapsulation efficiency of PS. After dynamic high-pressure microfluidization for 3 times at 120 MPa, the particle size of OP-PS particles can reach 139.28 nm with good re-dispersibility, and the encapsulation efficiency of PS is up to 98.63%, which can effectively improve the water-solubility and bioavailability of PS. The stability of OP-PS particles was evaluated. After 50 days of storage at room temperature, the encapsulation efficiency of PS was still about 66.90%, and the thermal stability was obviously better than that of soybean protein isolate-phytosterol particles prepared under the same conditions. The results of particle disulfide bond determination showed that high-pressure microfluidization could induce the formation and cross-linking of intramolecular or intermolecular disulfide bonds of protein. The free sulfhydryl and disulfide bonds of OP were significantly higher than those of SPI, and more disulfide bonds could be formed and cross-linked under high pressure homogenization. Therefore, OP-PS nanoparticles prepared by high pressure microjet technology have higher stability and sterol loading capacity, which can provide reference for industrial production of water-soluble sterols.
