乌饭树树叶色素与大米蛋白相互作用的研究

Interactions between Vaccinium bracteatum Thunb. Leaf Pigment and Rice Protein

摘要:

本文以乌饭树树叶（VBTL）色素和大米蛋白为研究对象，研究了乌饭树树叶染色过程中色素和大米蛋白间的相互作用，分析了染色前后VBTL色素抗氧化能力和游离多酚含量的变化，并对染色前后大米蛋白的表面疏水性和二级结构变化进行了分析研究。实验结果表明：染色过程能够显著降低乌饭树树叶色素溶液的抗氧化能力和多酚含量，分别降低了67.19%和68.11%；同时，染色也能够显著降低大米蛋白的亮度和表面疏水性，且两者的下降程度呈现高度的相关性。研究发现染色过程中，大米蛋白的二级结构发生变化，其中β-转角含量基本不变，α-螺旋与β-折叠含量下降，无规卷曲含量上升。另外，将大米蛋白分类提取后染色的实验结果表明：色素与清蛋白之间更易形成氢键，与谷蛋白和球蛋白之间更易形成疏水键。从以上结果分析可以推测色素与大米蛋白之间以疏水作用和氢键为主要结合手段。

Abstract:

Combined proteomic and biochemical strategies were used to study the interaction between Vaccinium bracteatum Thunb. Leaf (VBTL) pigment and rice protein. Changes in antioxidant activity and free polyphenol content of VBTL pigment were measured before and/or after the dyeing process. Changes in surface hydrophobicity and secondary structure of the protein were also analyzed. The results indicated that the antioxidant activity and free polyphenol content of VBTL pigment decreased by 67.19% and 68.11%, respectively, after dyeing the rice protein. Meanwhile, the brightness and surface hydrophobicity of rice protein decreased significantly. In addition, the dyeing process changed secondary structure of rice protein.. Briefly, there were significant reductions in the content of α-helix and β-sheet structures, but an obvious increase in random coil. Furthermore, the results indicated that albumin interacted more readily with VBTL pigment than did globulin or glutelin. All the data indicated that the VBTL pigment interacted with rice protein mainly via hydrophobic bonds and hydrogen bonds.