酪蛋白对乳清浓缩蛋白自组装形成纳米纤维的影响

Effect of Casein on Whey Protein Concentrate Self-assembling to Form Nano-fibril Polymers

某些蛋白质在非常规条件下可以自组装形成纳米纤维聚合物,这种聚合结构对蛋白质单体及其常规聚合形态赋予了高级功能性质,但这种自组装过程容易受其他蛋白的干扰,破坏其组装聚合方式。研究了乳液中2种主要蛋白成分的相互作用和酪蛋白(CN)对乳清浓缩蛋白(WPC)自组装形成纤维状聚合物的影响,分析了WPC在自组装的不同时期受CN的干扰程度。结果表明,在纤维形成不同阶段混入CN,决定了形成聚合物的结构形态,CN加入的时间越早,对纤维形成的抑制作用越明显,提高混入CN浓度,能够使形成纤维聚合物的CN混入时间点延后。其中表面疏水作用和二硫键的形成共同促进了CN与WPC的聚合,弱化了WPC的自身作用,继而抑制WPC的纤维自组装,在纤维形成初期混入CN,这种抑制作用尤为明显。CN的混入使聚合速率常数k增大,WPC与CN聚合能力增强,而WPC间的聚合作用减弱,干扰和破坏了WPC纤维聚合物的形成。研究表明,牛乳中酪蛋白的影响导致牛乳蛋白无法形成纳米纤维聚合物,除去牛乳中的酪蛋白,使分离出的乳清蛋白在自组装聚合的中后期混入酪蛋白,则不影响纳米纤维聚合结构的形成。

Proteins can self-assemble to form nano-fiber polymers under unconventional conditions.This kind of polymer structure given protein monomers and their conventional polymerization formed with high-level functional properties,but this self-assembly process was easily interfered by other proteins and destroyed the assembly and polymerization mode.The interaction of two main protein components in milk was explored,and the effect of casein(CN)on the self-assembly of whey protein concentrate(WPC)to form fibril polymers was studied,and the degree of interference of WPC by CN at different stages of self-assembly was analyzed.The results showed that incorporation of CN at different stages of fibril formation determined the structure and shape of the hybrid copolymer.The earlier CN was added,the more obvious the inhibitory effect on the fibril formation was.With the increase of CN concentration,the mixing time point of CN for the formation of fibril polymer was delated.Among them,the surface hydrophobic interaction and the formation of disulfide bonds promoted the polymerization of CN and WPC,which weakened the interaction between WPC itself,and then inhibited the self-assembly of WPC fibrils.This inhibition was particularly obvious when CN was mixed in the initial stage of fibril formation.The polymerization rate constant k and the polymerization ability of WPC and CN were increased and the polymerization between WPC was weakened.The formation of WPC fibril polymer was destroyed by the interference of CN.The results indicated that cow's milk protein cannot form nano-fibril polymers due to the effect of CN in cow's milk,but the casein in cow’s milk was removed,and mixed in the middle and late stages of WPC self-assembly polymerization did not affect the formation of nano-fibril polymer structure.