冷榨对大豆蛋白结构特性的影响研究

Effects of Cold-Pressing on Soybean Protein Structure Characteristics

冷榨工艺是将物料在低于60 ℃的环境温度下进行螺杆挤压提取油脂的一种方法。文章主要研究连续二次冷榨对物料的影响机制。通过傅里叶变换红外光谱、内源荧光光谱、表面疏水性、化学交联和溶解度、乳化活性和乳化稳定性、粒径、Zeta电位、消化特性等指标,探究不同冷榨次数对大豆蛋白的构效关系和消化性能的影响。结果表明:二次冷榨后大豆蛋白的α-螺旋结构相对含量增加,无规则卷曲结构减少,冷榨工艺增加了大豆蛋白的有序结构,结构更加紧密。冷榨工艺使大豆蛋白的最大发射波长发生蓝移,表面疏水性降低。二次冷榨后使得维持大豆蛋白构象的作用力被破坏,形成了聚集体,粒径增加,Zeta电位绝对值减小,溶解度下降,乳化活性和乳化稳定性减小。在体外模拟胃肠道消化过程中,冷榨处理暴露酶的作用点,体外消化率明显增加。该研究结果为冷榨工艺应用于大豆蛋白的加工过程提供了理论基础。

Cold-pressing process is a physical treatment of extracting oil from the material by screw extrusion below 60 ℃.This paper mainly studies the influence mechanism of continuous secondary cold pressing on materials.The effects of different cold pressing times on the structure-activity relationship and digestibility of soybean protein were studied by Fourier transform infrared spectroscopy,endogenous fluorescence spectroscopy,surface hydrophobicity,chemical crosslinking and solubility,emulsifying activity and emulsifying stability,particle size,zeta potential and digestion characteristics.The results showed that the content of soybean protein after secondary cold pressing α-helix structure increased and the random coil structure decreased.The cold pressing process increased the ordered structure of soybean protein and made the structure more compact.The cold pressing process made the maximum emission wavelength of soybean protein blue shift and the surface hydrophobicity decreased.After the second cold pressing,the force to maintain the conformation of soybean protein was destroyed and formed aggregates.The particle size increased,the absolute value of zeta potential decreased,the solubility decreased,and the emulsifying activity and emulsifying stability decreased.In the process of simulating gastrointestinal digestion in vitro,cold pressing treatment exposed the action point of enzyme,and the in vitro digestibility increased significantly.The results provide a theoretical basis for the application of cold pressing technology in the processing of soybean protein.