豆渣蛋白-植物甾醇纳米颗粒的制备及其性质表征

植物甾醇（Phytosterol，PS）具有多种优秀的生理活性，但较低的水溶性和生物可及性一直阻碍其被广泛应用。该研究以豆渣蛋白（Okara protein，OP）为原料，利用反溶剂法结合高压微射流技术制备了豆渣蛋白-植物甾醇纳米颗粒，并对其性质进行了表征。研究结果表明：高压微射流处理可显著降低OP-PS颗粒的粒径，明显提高PS的包埋率。在120 MPa高压微射流循环处理3次后，OP-PS颗粒的粒径可达到139.28 nm，PS包埋率高达98.63%，水溶重分散性良好。对OP-PS颗粒进行稳定性评估，发现常温贮藏50 d后，甾醇包埋率仍能保持在66.90%左右，且热稳定性明显优于同等条件下制备的大豆分离蛋白-植物甾醇颗粒（SPI-PS）。可能的原因是，OP的游离巯基及二硫键明显高于SPI，高压微射流能诱导蛋白分子内或分子间二硫键的形成与交联，可以有效提高纳米颗粒的稳定性。高压微射流技术制备的OP-PS纳米颗粒具有较高的稳定性和甾醇荷载能力，能够为工业生产水溶性甾醇提供借鉴。

Preparation and Characterization of Okara Protein-phytosterol Nanoparticles

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.