摘要：本文以乳清蛋白为研究目标，探讨超声-疏水性离子液体处理对蛋白质结构特征的影响。分别通过巯基和二硫键含量、红外光谱、表面疏水性、荧光光谱、紫外光谱、扫描电镜和Zeta电位等方法分析超声-疏水性离子液体处理后乳清蛋白的结构特征变化。结果表明：超声-疏水性离子液体处理后，乳清蛋白的巯基含量明显增加，而二硫键含量明显降低。红外光谱分析表明了超声-疏水性离子液体处理引起了乳清蛋白的二级结构（α-螺旋、β-折叠、β-转角和无规则卷曲）发生了变化；荧光光谱分析表明超声-疏水性离子液体处理提高了乳清蛋白的表面疏水性。超声-疏水性离子液体处理提高了270-290nm处的吸收峰，降低了乳清蛋白的Zeta电位。扫描电镜分析表明超声-疏水性离子液体处理减小了乳清蛋白颗粒；聚丙烯酰胺凝胶电泳（SDS-PAGE）分析表明超声-疏水性离子液体处理对乳清蛋白分子量没有明显影响。总之，超声-疏水性离子液体处理后，乳清蛋白的结构发生了变化。

关键词：乳清蛋白；超声-疏水性离子液体；处理；结构特征

Abstract：To explore the effect of ultrasonic-hydrophobic ionic liquid (UHIL) treatment on protein structure characteristics, whey protein was used as an experiment material in this paper. After UHIL treatment, the structural characteristics of whey protein were analyzed by contents of free sulfhydryl and disulfide bond, infrared spectroscopy, surface hydrophobicity, fluorescence spectroscopy, ultraviolet spectroscopy, scanning electron microscopy and Zeta potential. The results showed that contents of free sulfhydryl of whey protein were increased while its disulfide bond contents were significantly decreased. Infrared spectroscopy analysis showed that the secondary structure of the whey protein (α-helix, β-fold, β-turn and random curl) was changed after UHIL treatment. Fluorescence spectroscopy showed that UHIL treatment improved the hydrophobicity of whey protein. UHIL treatment increased the absorption peak at 270-290 nm, while decreased its zeta potential. Scanning electron microscopy (TEM) showed that UHIL treatment reduced the whey protein particles. SDS-Polyacrylamide gel electrophoresis (PAGE) analysis showed that the UHIL treatment had no significant effect on the molecular weight of whey protein. In conclusion, the structure of whey protein has changed after UHIL treatment.

Keywords: whey protein; ultrasound-hydrophobic ionic liquids; treatment; structural characteristics

目录

第一章绪论1

1.1乳清蛋白概述1

1.1.1乳清蛋白1

1.1.2乳清蛋白的成分和功能2

1.1.3乳清蛋白的分类2

1.1.4乳清蛋白的应用3

1.2乳清蛋白的结构的功能性质4

1.2.1乳清蛋白的结构4

1.2.2乳清蛋白的功能性质5

1.3研究意义和内容·6

1.3.1研究意义·6

1.2.2研究内容·8

第二章实验材料与方法9

2.1实验试剂和仪器·9

2.1.1实验试剂·9

2.1.2实验仪器·9

2.2实验方法··9

2.2.1乳清蛋白的超声-疏水性离子液体耦合处理··9

2.2.2乳清蛋白巯基和二硫键含量的测定9

2.2.3乳清蛋白的傅里叶红外光谱测定·10

2.2.4乳清蛋白表面疏水性的测定···10

2.2.5乳清蛋白zeta电位的测定··10

2.2.6乳清蛋白SDS-PAGE电泳的测定11

2.2.7乳清蛋白紫外吸收光谱的测定11

2.2.8乳清蛋白微观形态的观察··11

第三章结果与分析12

3.1乳清蛋白巯基和二硫键含量的变化···12

3.2乳清蛋白的傅里叶红外光谱分析··17