摘要
目的基于超高温(ultra-high temperature,UHT)乳的加工过程,探究不同变性程度β-乳球蛋白(β-lactoglobulin,β-Lg)与纤溶酶的互作及形成复合体的理化性质。方法β-Lg经过预热和UHT处理后,利用小角X射线散射明确了不同变性程度的β-Lg与纤溶酶的结合状态,通过动态光散射表征了聚集体的粒径。采用傅里叶红外光谱、圆二色谱、内源荧光和紫外光谱分析了β-Lg与纤溶酶的结合基团,以及聚集体的结构性质;原子力显微镜结合透射电镜揭示聚集体的形貌特征。结果β-Lg能与纤溶酶结合形成二聚体,该聚集体粒径为20~220nm。热变性导致β-Lg二级结构无序化,三级结构展开,进而增强了其与纤溶酶之间的氢键作用,最终形成了球状或不规则形貌的聚集体。结论β-Lg与纤溶酶通过非共价作用形成复合体,且变性促进了β-Lg与纤溶酶的结合。该研究为优化低纤溶酶活力UHT乳的加工参数提供了新观点,对延长UHT乳货架期和开发新型纤溶酶抑制剂提供了理论依据。
Objective To explore the interaction betweenβ-lactoglobulin(β-Lg)and plasmin in different degrees of denaturation and the physical and chemical properties of complex formation based on the processing of ultra-high temperature(UHT)milk.Methods Afterβ-Lg was preheated and treated with UHT,small-angle X-ray scattering clarified the binding state betweenβ-Lg with different degrees of denaturation and plasmin,and dynamic light scattering characterized the particle size of the aggregates.Furthermore,Fourier-transform infrared spectroscopy,circular dichroism,intrinsic fluorescence,and ultraviolet spectroscopy analyzed the binding groups betweenβ-Lg and plasmin,as well as the structural properties of the aggregates.Atomic force microscopy combined with transmission electron microscopy revealed the morphology of the aggregates.Resultsβ-Lg could bind with plasmin to form dimers,with aggregate sizes ranging from 20 nm to 220 nm.Thermal denaturation caused the disordering of the secondary structure ofβ-Lg structure and the unfolding of its tertiary structure,thereby enhancing hydrogen bonding interactions with plasmin and ultimately forming spherical or irregularly shaped aggregates.Conclusionβ-Lg and plasmin form complexes through non-covalent interactions,and denaturation promotes the binding ofβ-Lg with plasmin.This study provides new insights into optimizing processing parameters for UHT milk with low plasmin activity,and offers a theoretical basis for extending the shelf life of UHT milk and developing new plasmin inhibitors.
作者
张太
刘伊索
曹佳媛
陈志伟
易华西
ZHANG Tai;LIU Yi-Suo;CAO Jia-Yuan;CHEN Zhi-Wei;YI Hua-Xi(College of Food Science and Engineering,Ocean University of China,Qingdao 266000,China;Zhongyuan Food Laboratory,Luohe 462300,China;Institute of Food and Nutrition Science,Shandong University of Technology,Zibo 255000,China)
出处
《食品安全质量检测学报》
CAS
2024年第15期191-198,共8页
Journal of Food Safety and Quality
基金
山东省重点研发计划项目(2023CXGC010711)
国家自然科学基金重点项目(32130081)。
关键词
Β-乳球蛋白
纤溶酶
超高温
交互作用
β-lactoglobulin
plasmin
ultra-high temperature
interaction
