超高压协同TG酶改性蛋清蛋白热诱导凝胶机理

Mechanism of Ultra-high Pressure and TG Enzyme Modified Thermally Induced Gels of Egg White Protein

为提高蛋清蛋白凝胶性,本研究以蛋清蛋白(Egg white protein,EWP)为研究对象,通过分析质构、持水率、分子作用力、傅里叶红外色谱、圆二色谱、粒径、电位、巯基含量、表面疏水力及扫描电镜的变化,探究超高压处理(Ultra-high pressure,UHP)、谷氨酰胺转胺酶处理(Transglutaminase,TG)及超高压协同TG酶处理(Ultra-high pressure synergistic Transglutaminase,UTG)的蛋清蛋白热诱导凝胶机理及结构的变化。结果表明:UHP-EWP、TG-EWP、UTG-EWP的硬度、弹性和持水性均有所提高,疏水相互作用力是维持凝胶的主要作用力;UHP-EWP、TG-EWP、UTG-EWP的α-螺旋含量均不同程度下降、β-折叠含量均上升;UHP-EWP的平均粒径值下降、电位绝对值下降,TG-EWP、UTG-EWP的变化与之相反;UHP-EWP、TG-EWP、UTG-EWP的游离巯基含量上升、总巯基含量下降、表面疏水性升高;凝胶结构更加致密光滑,平整度提高。本研究为蛋清蛋白热诱导凝胶改性提供了理论基础及研究思路。

Aiming to improve the gel property of egg white proteins,in this research,taking egg white protein(EWP)as the research object,the changes in texture,water-holding ratio,molecular forces,Fourier transform infrared chromatography,circular dichroism spectrum,particle size,potential,sulphydryl content,surface hydrophobicity,and scanning electron microscopy were analyzed to explore the mechanism and structural changes of heat-induced gel of EWP after the treatments of Ultra-high Pressure(UHP),Transglutaminase(TG)and Ultra-high Pressure Synergistic Transglutaminase(UTG).The results showed that the hardness,elasticity and water holding capacity of UHP-EWP,TG-EWP and UTG-EWP were all improved,and hydrophobic interaction was the main force to maintain gel.Theα-helix content of UHP-EWP,TG-EWP and UTG-EWP decreased,while theβ-fold content increased.The average particle size and absolute potential of UHP-EWP decreased,while the changes of TG-EWP and UTG-EWP were opposite.The content of free sulfhydryl groups in UHP�EWP,TG-EWP,and UTG-EWP increased,the content of total sulfhydryl groups decreased,and the surface hydrophobicity increased.The gel structure was more compact and smooth,and the flatness was improved.This research provides a theoretical basis and research ideas for the heat induced gel modification of EWP.