College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China.
College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China.
Food Chem. 2021 Oct 1;358:129821. doi: 10.1016/j.foodchem.2021.129821. Epub 2021 Apr 20.
The present study investigated the effects of dielectric-barrier-discharge (DBD) plasma treatment (12 kHz, 40 kV) at 1, 2, 3, and 4 min on the reduction of the immunoglobulin G (IgG) binding capacity of β-lactoglobulin (β-LG). The IgG binding capacity of β-LG was reduced by 58.21% following a plasma treatment time of 4 min, as confirmed by western-blot and ELISA analyses. The reduction in IgG binding capacity of β-LG was directly related to a stepwise change in its structure. The initial drop in the IgG binding capacity of β-LG was found to be caused by conformational alteration, free sulfhydryl exposure and cross-linkage of molecules induced by oxidation of NH-/NH- functional groups of peptide bonds and of sensitive amino acid residues (Tyr, Trp) as confirmed by SDS-PAGE, surface hydrophobicity and multi-spectroscopic analyses. Plasma treatment of more than 3 min resulted in cleavage of disulfidebonds and fragmentation of β-LG that was confirmed by LC-MS/MS analysis, which resulted a further decline in the IgG binding capacity of β-LG. Plasma treatment therefore has great potential as a substitute treatment for enzymatic hydrolysis for the production of hypoallergenic milk protein-based products.
本研究考察了介质阻挡放电（DBD）等离子体处理（12 kHz，40 kV）1、2、3 和 4 分钟对β-乳球蛋白（β-LG）免疫球蛋白 G（IgG）结合能力降低的影响。经 4 分钟等离子体处理后，β-LG 的 IgG 结合能力降低了 58.21%，这一点通过 Western blot 和 ELISA 分析得到了证实。β-LG 的 IgG 结合能力的降低与结构的逐步变化直接相关。研究发现，β-LG 的 IgG 结合能力的最初下降是由构象改变、游离巯基暴露以及由肽键和敏感氨基酸残基（Tyr、Trp）的 NH-/NH- 功能基团氧化引起的分子交联引起的，这一点通过 SDS-PAGE、表面疏水性和多光谱分析得到了证实。超过 3 分钟的等离子体处理会导致二硫键的断裂和β-LG 的片段化，这一点通过 LC-MS/MS 分析得到了证实，这导致了β-LG 的 IgG 结合能力进一步下降。因此，等离子体处理作为酶水解替代方法用于生产低致敏性乳蛋白基产品具有很大的潜力。
