百里香酚纳米复合诱导大豆蛋白自组装凝胶及机制

Self-assembly Soy Protein Gel Based on Thymol Nanocomplexation and Its Molecular Mechanism

摘要:

为了揭示百里香酚纳米复合诱导大豆蛋白自组装凝胶的途径及机制，该文研究了蛋白浓度、百里香酚添加量、反应初始pH值和反应终止pH值对大豆蛋白与百里香酚相互作用及其凝胶形成的影响。结果表明：四者协同调控大豆蛋白-百里香酚纳米复合物凝胶的形成，百里香酚荷载量的提高可降低大豆蛋白凝胶的临界蛋白浓度（75 mg/mL），反应结束后调节pH值至中性是凝胶形成的必要条件。在pH值为7.0条件下，百里香酚复合诱导大豆蛋白产生了明显的纤维化聚集，其颗粒平均粒径增加27.60%、光散射强度提高154.67%、Th T荧光强度提高93.78%，因此推测百里香酚复合主要通过诱导大豆蛋白纤维化聚集的产生继而诱导凝胶的形成。大豆蛋白-百里香酚纳米复合物凝胶在尿素和DTT溶液中的溶解度提高，因而推测维持凝胶网络的分子间相互作用力主要为氢键、疏水相互作用力和二硫键。研究结果为大豆蛋白冷致凝胶提供了新的技术解决方案，并为百里香酚的开发利用提供理论支撑。

Abstract:

In order to reveal the approach and mechanism of soy protein self-assembly gel based on thymol nanocomplexation, the effects of protein concentration, thymol addition concentration, as well as initial and final pH value of the reaction on soy protein-thymol interaction and gel formation were investigated in the present study. The results showed that all the factors synergistically regulated the formation of soy protein-thymol nanocomplex gel. A higher thymol loading amount facilitated the formation of soy protein gel with a lower critical protein concentration (75 mg/mL). Additionally, the pH value adjusted to neutral at the end of complexation was necessary for soy protein-thymol nanocomplex gel formation. Considering that the average particle size and light scattering intensity of particles, as well as Th T fluorescence intensity of soy protein were increased by 26.70%, 154.67% and 93.78%, respectively at a pH of 7.0, the soy protein gel formation could have been largely associated with the fibrous aggregation that occurred in the soy protein after thymol nanocomplexation. The solubility of prepared gel in urea and DTT was increased, thus it is assumed that the intermolecular interaction forces that maintain the soy protein gel network were mainly hydrogen bonding, hydrophobic interactions, and disulfide bonding. Thus, the findings are important for developing cold-set soy protein gels and utilizing thymol.