不同缓冲体系下超高压处理对乳铁蛋白结构及理化性质的影响  

Effect of Super High Pressure Processing on the Structure and Physicochemical Properties of Lactoferrin in Different Buffer Systems

作　　者：何晓叶[1,2] 任爽 郑伊琰 高彦祥 袁芳[1] He Xiaoye;Ren Shuang;Zheng Yiyan;Gao Yanxiang;Yuan Fang(College of Food Science&Nutritional Engineering,China Agricultural University,Key Laboratory of Functional Dairy,Ministry of Education,Beijing 100083;Institute of Food and Nutrition Development,Ministry of Agriculture and Rural Affairs of the People's Republic of China,Beijing 100081)

机构地区：[1]中国农业大学食品科学与营养工程学院教育部功能乳品重点实验室,北京100083 [2]农业农村部食物与营养发展研究所,北京100081

出　　处：《中国食品学报》2021年第5期174-184,共11页Journal of Chinese Institute Of Food Science and Technology

基　　金：北京市自然科学基金项目(6192015)。

摘　　要：本文通过测定Zeta电位、游离巯基含量、紫外光谱、荧光光谱、圆二色谱和蛋白质溶解性,研究不同缓冲体系【(磷酸盐缓冲液(PBS)、Tris-HCl缓冲液(Tris-HCl)、柠檬酸盐缓冲液(CBS)】下超高压处理对乳铁蛋白(LF)结构和理化性质的影响。结果表明:3种缓冲液中LF对超高压的抗性如下:CBS>Tris-HCl>PBS,即LF在PBS中的三级结构和溶解性最容易被超高压改变。缓冲溶液中阴离子的吸附能力导致LF的等电点发生变化;PBS、CBS、Tris-HCl 3种缓冲液中LF表面Zeta电位分别为-3.86~20.07,-6.89~19.6 mV和1.24~23.37 mV,因此阴离子的吸附能力CBS>PBS>Tris-HCl。pH 7的Tris-HCl缓冲液中600 MPa处理的LF产生大量沉淀,游离巯基含量达到最高,为6.23μmol/(L·g),蛋白溶解度最低,为45.28μg/mL。pH为3时LF的α-螺旋含量显著低于其它样品,无规卷曲含量显著高于其它样品,表明LF的二级结构在酸性条件下会变松弛,并且更容易受到高压的影响。This paper measured the effect of high pressure processing on the structure and properties of lactoferrin(LF)in different buffer systems[(phosphate buffer(PBS),Tris-HCl buffer(Tris-HCl),citrate buffer(CBS)]by Zeta potential,free sulfhydryl content,ultraviolet spectrum,fluorescence spectrum,circular dichroism and protein solubility.The results showed that the resistance of LF to high pressure in the three buffers was as follows:CBS>Tris-HCl>PBS,that was,the tertiary structure and solubility of LF in PBS were most easily changed by high pressure.The adsorption of anions in the buffer solution caused the isoelectric point of LF to change.The surface Zeta potential of LF in PBS,CBS,and Tris-HCl was-3.86-20.07,-6.89-19.6 mV and 1.24-23.37 mV,respectively.Accordingly,the adsorption capacity of anions was CBS>PBS>Tris-HCl.600 MPa treatment in Tris-HCl at pH 7 caused a large amount of precipitation of LF,where the free sulfhydryl content reached the highest,6.23μmol/(L·g),and the protein solubility was the lowest,45.28μg/mL.At pH 3,theα-helix content of LF was significantly lower than other samples,and the content of random coils was significantly higher than other samples,indicating that the secondary structure of LF was relaxed under acidic condition and was more susceptible to high pressure.

关 键 词：超高压 乳铁蛋白 缓冲体系 结构 理化性质 

分 类 号：TS201.21[轻工技术与工程—食品科学]