关键词: 豆乳粉, 微流化, 表面疏水性, 巯基含量, 溶解性

Abstract: Microfluidization was introduced into the traditional wet process for preparing soymilk powder. After okara separation, soymilk was microfluidized at pressures of 0, 42.5, 89.0, 123.5 or 152.0 MPa. Our aim was to study the effect of microfluidization on the structure and solubility of soymilk powder protein. The results demonstrated that free sulfhydryl content, volume average particle size and surface hydrophobicity of the microfluidized samples were significantly higher than those of the untreated ones (P < 0.05). At a microfluidization pressure of 123.5 MPa, the protein surface hydrophobicity reached its the maximum value, an increase of 1.6 times compared with that of the untreated samples. Similarly, the content of free sulfhydryl groups reached its maximum level of 7.62 μmol/g, an increase of 24.96% compared with that of the untreated samples. Moreover, the soymilk powder produced had the smallest volume average particle size and particle size distribution width, and its maximum solubility was 79.47%. However, when the pressure was increased to 152.0 MPa, the solubility of the soymilk powder decreased.

Key words: soybean powder, microfluidizer, surface hydrophobicity, sulfhydryl content, solubility