Abstract：
The effect of microfluidization treatment on the primary, secondary, and tertiary structure of soybean protein isolate (SPI) was investigated. The samples were treated with and without controlling the temperature and circulated in the system 1, 3, and 5 times at high pressure (137 MPa). Then, the treated samples were freeze-dried and reconstituted in water to check the impact of the microfluidization on two different states: powder and solution. Regarding the primary structure, the SDS-PAGE analysis under reducing conditions showed that the protein bands remained unchanged when exposed to microfluidization treatment. When the temperature was controlled for the samples in their powder state, a significant decrease in the quantities of β-sheet and random coil and a slight reduction in α-helix content was noticed. The observed decrease in β-sheet and the increase in β-turns in treated samples indicated that microfluidization may lead to protein unfolding, opening the hydrophobic regions. Additionally, a lower amount of α-helix suggests a higher protein flexibility. After reconstitution in water, a significant difference was observed only in α-helix, β-sheet and β-turn. Related to the tertiary structure, microfluidization increases the surface hydrophobicity. Among all the conditions tested, the samples where the temperature is controlled seem the most suitable.
摘要：
微流化处理对初级,次要,研究了大豆分离蛋白(SPI)的三级结构。在控制和不控制温度的情况下处理样品,并在高压(137MPa)下在系统中循环1、3和5次。然后，将处理过的样品冷冻干燥并在水中重构，以检查微流化对两种不同状态的影响：粉末和溶液。关于一级结构，还原条件下的SDS-PAGE分析表明，当暴露于微流化处理时，蛋白质条带保持不变。当控制粉末状态的样品的温度时，注意到β-折叠和无规卷曲的数量显着减少，而α-螺旋含量略有减少。在处理过的样品中观察到的β-折叠的减少和β-转角的增加表明微流化可能导致蛋白质解折叠,打开疏水区域。此外,较低的α-螺旋表明较高的蛋白质灵活性。在水中复原后,仅在α-螺旋中观察到显著差异，β-折叠和β-转角。与三级结构相关，微流化增加了表面疏水性。在所有测试的条件中，控制温度的样品似乎最合适。
