莲子中不同蛋白的结构及理化特性对比分析

Comparative Analysis of the Structural and Physicochemical Properties of Different Proteins in Lotus Seeds

摘要:

该研究分别制备了莲子分离蛋白与莲子分级蛋白（清蛋白、球蛋白、醇溶蛋白、谷蛋白），并对比研究了不同莲子蛋白的溶解性、乳化性、分子特性等结构变化。研究结果表明，莲子中蛋白质约占干基总量的16.14%，4种分级蛋白所占比例依次约为55:6:0.1:25。对比5种不同莲子蛋白，清蛋白溶解性最高，Zeta电位最低值为-21.3 mV，粒径最小值为75.47 μm，分离蛋白乳化性最好，五种不同蛋白的等电点均在4.9附近。光谱研究表明，醇溶蛋白和谷蛋白荧光更强，清蛋白和球蛋白α-螺旋含量更低，醇溶蛋白和谷蛋白β-转角含量更高。光谱研究表明，分离蛋白、清蛋白（球蛋白）的波长蓝移，清蛋白和球蛋白的α-螺旋含量更低，且α-螺旋、β-折叠、β-转角含量也发生不同变化。这些研究结果也表明清蛋白和球蛋白分子柔性相对更高，与其溶解性、乳化性、疏水性密切相关。通过实验有助于揭示莲子分离蛋白和分级蛋白理化特性与分子结构间的构效关系，并为深入研究莲子蛋白的功能特性提供理论依据。

Abstract:

Lotus seed protein isolates and lotus seed fractionated proteins (albumin, globulin, prolamin, glutenin) were extracted, and the solubility, emulsification, molecular properties, and structural properties were compared. The results showed that protein in lotus seeds accounts for about 16.14% of the total dry weight, and the proportion of four graded proteins was about 55:6:0.1:25. Respectively, compared with the five different lotus seed proteins, The solubility of albumin was the highest, the Zeta potential had the lowest value of -21.3 mV, the particle size had the minimum value of 75.47 μm, and the emulsification of the isolated protein was the best. The isoelectric points of five different proteins were all around 4.9. Spectroscopic studies have shown that gliadin and glutenin fluoresce more strongly, the content of albumin and globulin α-helix was lower, while the content of gliadin and glutenin β-turn was higher. These results also indicate that the molecular flexibility of albumin and globulin is higher, which is closely related to solubility, ability to emulsify, and hydrophobicity. The experiments revealed the active structural relationship between the physicochemical properties and molecular structure of lotus seed protein isolates and fractionated proteins. This provides a theoretical basis for the further study of the functional properties of lotus seed protein.