Department of Food Science and Engineering, College of Biological Sciences and Biotechnology, Beijing Key Laboratory of Forest Food Processing and Safety, Beijing Forestry University, Beijing, China.
Department of Science and Engineering, Hebei Agricultural University, Cangzhou, China.
J Sci Food Agric. 2023 Aug 15;103(10):4908-4918. doi: 10.1002/jsfa.12559. Epub 2023 Mar 29.
Native walnut protein is an alkali-soluble protein that seriously limits the application of walnut protein. The pH-shifting method could improve the solubility of walnut proteins and enable the encapsulation of active ingredients. The present study aimed to prepare water-soluble nanoparticles of curcumin using walnut protein and evaluate the process of walnut protein self-assembly, interaction between walnut protein and curcumin, encapsulation properties, and stability of nanoparticles.
The solubility of native walnut protein was poor, but the solubility of walnut protein nanoparticles (WPNP) formed by walnut protein after pH-shifting significantly improved to 91.5 ± 1.2%. This is because, during the process of pH changing from 7 to 12 and back to 7, walnut protein first unfolded under alkaline conditions and then refolded under pH drive, finally forming an internal hydrophobic and external hydrophilic shell-core structures. The quenching type of walnut protein and curcumin was static quenching, and the quenching constant was 2.0 × 10 mol L s , indicating that the interaction between walnut protein and curcumin was non-covalent. Adding curcumin resulted in the formation of nanoparticles with small particle size compared with the no-load. The loading capacity of curcumin-loaded walnut protein nanoparticles (WPNP-C) was 222 mg g walnut protein isolate. Under the same mass, the curcumin equivalent concentration in aqueous solution of WPNP-C was 17 000 times higher than that of the native curcumin.
The solubility of the self-assembled WPNP significantly increased after pH-shifting treatment. The walnut protein carrier could improve the stability of the encapsulated curcumin. Therefore, walnut proteins could be used as water-soluble carriers for hydrophobic drugs. © 2023 Society of Chemical Industry.
天然核桃蛋白是一种堿溶性蛋白，严重限制了核桃蛋白的应用。pH 值变换法可提高核桃蛋白的溶解度，实现活性成分的包封。本研究旨在利用核桃蛋白制备姜黄素的水溶性纳米粒子，并评价核桃蛋白自组装过程、核桃蛋白与姜黄素之间的相互作用、纳米粒子的包封特性和稳定性。
天然核桃蛋白的溶解度较差，但经 pH 值变换形成的核桃蛋白纳米粒子（WPNP）的溶解度显著提高到 91.5±1.2%。这是因为在 pH 值从 7 变为 12 再变回 7 的过程中，核桃蛋白首先在堿性条件下展开，然后在 pH 驱动下重新折叠，最终形成内部疏水和外部亲水的核壳结构。核桃蛋白和姜黄素的猝灭类型为静态猝灭，猝灭常数为 2.0×10 mol L s ，表明核桃蛋白与姜黄素之间的相互作用是非共价的。加入姜黄素导致形成的纳米粒子比未负载时的粒子尺寸更小。载姜黄素的核桃蛋白纳米粒子（WPNP-C）的载药量为 222mg g 核桃蛋白分离物。在相同质量下，WPNP-C 水溶液中姜黄素的等效浓度比天然姜黄素高 17000 倍。
自组装 WPNP 经 pH 值变换处理后溶解度显著提高。核桃蛋白载体可提高包封姜黄素的稳定性。因此，核桃蛋白可用作疏水性药物的水溶性载体。 © 2023 化学工业协会。
