不同分子量的葡聚糖-花生分离蛋白接枝复合物的制备及其性质

通过不同分子量葡聚糖与花生分离蛋白发生接枝反应形成共价聚合物,并对它们的结构特性、功能特性和所形成乳浊液的流变学特性进行分析,多角度探讨葡聚糖分子量对花生分离蛋白结构及其乳浊液性质的影响并阐释原因。对接枝产物的接枝度结果测定证明了接枝反应的发生,且随着葡聚糖分子量的增加,接枝程度越低。共价聚合物的二级和三级结构都发生了改变,二级结构中α-螺旋结构减少,β-转角结构增多,以20 kDa分子量的葡聚糖与花生分离蛋白接枝形成的共价聚合物PDC2变化较为明显;三级结构中,PDC2变得更加松散,结构的变化引起其分子间疏水作用力增加,表面疏水性指数达到783±19,在其乳浊液体系中,内部分子间离子作用力明显,抗剪切作用力较大,这些作用力维持着乳浊液体系的稳定性。葡聚糖接枝能够改善花生分离蛋白的功能特性,其中以20 kDa分子量的葡聚糖改善程度最为明显,为拓宽花生分离蛋白在食品工业中的应用提供了一定的依据。

Preparation and Properties of Grafted Conjugates with Dextran in Different Molecular Weights-Peanut Protein Isolates

A covalent polymer was formed by the graft reaction of different molecular weight glucans and peanut protein isolates,and their structural characteristics and rheological properties of the formed emulsion were analyzed.The influence of the molecular weight of glucan on the structural and emulsion properties of peanut protein isolate were observed at multiple angles and the reasons were explained.The grafting degree of the grafted product confirmed the occurrence of the grafting reaction,and the grafting degree was lower with the increase of the molecular weight of dextran.The secondary and tertiary structures of the covalent polymers had changed,the α-helical structure reduced in the secondary structure,the β-turn structure increased.The change of PDC2,a covalent polymer formed by the grafting of 20 kDa molecular weight dextran onto peanut protein isolate,was more obvious.In the tertiary structure,PDC2 became looser.The surface hydrophobicity index of PDC2 increased obviously,reached 783 ± 19,indicating that the intermolecular hydrophobic force was greater.In the emulsion system,the intermolecular intermolecular force was obvious,and the resistance shearing force was greater.The force maintained the stability of the emulsion system.Dextran grafting could improve the functional properties of peanut protein isolates.Among them,the improvement of dextran with molecular weight of 20 kDa was the most obvious,which provided a certain basis for broadening the application of peanut protein isolates in the food industry.