食品科学 ›› 2021, Vol. 42 ›› Issue (8): 29-39.doi: 10.7506/spkx1002-6630-20200724-329

• 食品化学 • 上一篇    下一篇

NaCl浓度对麦醇溶蛋白与槲皮素相互作用的影响

王启明,唐瑜婉,李春翼,赵吉春,张宇昊,明建   

  1. (1.西南大学食品科学学院,重庆 400715;2.西南大学食品贮藏与物流研究中心,重庆 400715)
  • 出版日期:2021-04-25 发布日期:2021-05-14
  • 基金资助:
    “十三五”国家重点研发计划重点专项(2016YFD0400203);国家自然科学基金面上项目(31771970)

Spectroscopic Analysis of Interaction between Gliadin and Quercetin under Different NaCl Concentrations

WANG Qiming, TANG Yuwan, LI Chunyi, ZHAO Jichun, ZHANG Yuhao, MING Jian   

  1. (1. College of Food Science, Southwest University, Chongqing 400715, China; 2. Research Center of Food Storage & Logistics, Southwest University, Chongqing 400715, China)
  • Online:2021-04-25 Published:2021-05-14

摘要: 利用荧光光谱、紫外光谱、傅里叶变换红外光谱法,研究不同NaCl浓度下麦醇溶蛋白(gliadin,G)与槲皮素(quercetin,Q)的相互作用。荧光光谱分析结果表明:不同NaCl浓度下,Q导致G荧光猝灭现象的发生,且随NaCl浓度的增大,荧光强度伴随明显蓝移现象(10?nm左右);当Q浓度为50?μmol/L时,荧光猝灭率为96%~98%,表明两者发生强相互作用;Q对G产生静态或动、静态结合的猝灭作用;50?mmol/L?NaCl浓度下,G与Q的结合常数(Ka)和结合位点数(n)数值最大,为4.87×107?L/mol和1.477?1,说明添加适量NaCl有利于相互作用的增强。热力学数据分析结果表明:50?mmol/L?NaCl浓度下,G与Q之间主要为疏水作用力,而其他NaCl浓度下,G与Q之间主要为氢键相互作用。同步光谱和紫外光谱分析结果表明:Q改变了G中芳香族氨基酸所处的微环境,使蛋白分子构象发生变化,且色氨酸残基对蛋白固有荧光的猝灭贡献更大。傅里叶变换红外光谱和拉曼光谱分析结果表明:在特定NaCl浓度下G与Q存在特定作用方式,氢键或疏水相互作用在复合物的形成中起重要作用,蛋白质的二级、三级结构及氨基酸侧链微环境发生改变。研究结果证明,NaCl浓度影响蛋白-多酚的相互作用,添加适量NaCl有利于G和Q的结合以及蛋白质的构象变化。本研究为Q作为一种天然食品添加剂应用于小麦制品提供了理论基础和科学依据。

关键词: 麦醇溶蛋白;槲皮素;NaCl浓度;相互作用

Abstract: The interaction between gliadin (G) and quercetin (Q) under different NaCl concentrations was studied by fluorescence spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The results showed that at all NaCl concentrations, Q led to fluorescence quenching of G accompanied by a distinct blue shift (about 10 nm) of the fluorescence intensity with increasing NaCl concentration. When the concentration of Q was 50 μmol/L, 96%–98% of the protein fluorescence was quenched, indicating that strong interactions existed between G and Q. Q quenched the fluorescence intensity of G through static and static-dynamic modes. At 50 mmol/L NaCl concentration, the association constant (Ka) and the number of binding sites (n) were the largest, 4.87 × 107 L/mol and 1.477 1, respectively, indicating stronger interactions between G and Q at proper salt concentration. Thermodynamic data indicated that hydrophobic interaction was responsible for the formation of complexes at 50 mmol/L NaCl concentration, while hydrogen bonding was the main driving force at other NaCl concentrations. Synchronous fluorescence and UV-Vis spectroscopy suggested that Q changed the microenvironment surrounding the aromatic amino acid residues and the protein conformation. Tryptophan residues greatly contributed to quenching the protein fluorescence. FTIR spectroscopy and Raman spectroscopy revealed that specific interaction modes of G with Q existed at specific NaCl concentrations, and hydrogen bonding and hydrophobic interaction played important roles in the formation of the complexes, changing the secondary and tertiary structures and the microenvironment around the amino acid side chain of G. The above results proved that NaCl concentration influenced protein-polyphenol interaction; adding proper NaCl concentrations could facilitate the binding between gliadin and quercetin and changes in protein conformation. Our study provides a theoretical basis for the development of quercetin as a natural food additive in wheat products.

Key words: wheat gliadin; quercetin; NaCl concentration; interaction

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