Li Ruiling, Wu Na, Xue Hui, Gao Binghong, Liu Huilan, Han Tianfeng, Hu Xiaobo, Tu Yonggang, Zhao Yan
Engineering Research Center of Biomass Conversion, Ministry of Education, Nanchang University, Nanchang 330047, China.
Jiangxi Key Laboratory of Natural Products and Functional Food, Jiangxi Agricultural University, Nanchang 330045, China; Agricultural Products Processing and Quality Control Engineering Laboratory of Jiangxi, Jiangxi Agricultural University, Nanchang 330045, China.
Colloids Surf B Biointerfaces. 2023 Mar;223:113182. doi: 10.1016/j.colsurfb.2023.113182. Epub 2023 Jan 31.
In this study, disulfide bonds between the interfacial protein film formed on the lipid particles and the protein in ovalbumin emulsion gels were blocked with 0, 1, 3, 5 and 10 mM of the N-ethylmaleimide (NEM) to explore the influence and effect mechanism of disulfide bonds between the interfacial proteins on the physicochemical properties, microstructure, and protein structure of sunflower oil-ovalbumin emulsion gels. Ovalbumin emulsion gels with NEM-treated ovalbumin emulsion (N-OE) had lower hardness, free sulfhydryl content, water holding capacity (WHC), and surface hydrophobicity, but higher spin-spin relaxation time (T) than ovalbumin emulsion gels with NEM-treated ovalbumin substrate solution (N-OSS). In addition, N-OE and N-OSS had lower hardness, free sulfhydryl content, WHC and surface hydrophobicity, as well as a more coarse and disordered microstructure than non-NEM treated ovalbumin emulsion gel (control group). The free sulfhydryl content, hardness, WHC, and surface hydrophobicity of the ovalbumin emulsion gels all decreased as the NEM concentration rose (p < 0.05), whereas the amide A band changed to higher wave numbers. These results collectively indicated that the reduction of disulfide between the interfacial layer and the proteins inhibited the hydrophobic effect, the formation of hydrogen bonds, and prevented the formation of larger aggregates. Thus the disulfide bonds between the interfacial proteins contribute to the hardness enhancement and water stabilization of the ovalbumin gel.
在本研究中，用0、1、3、5和10 mM的N - 乙基马来酰亚胺（NEM）阻断脂质颗粒上形成的界面蛋白膜与卵清蛋白乳液凝胶中蛋白质之间的二硫键，以探究界面蛋白之间的二硫键对葵花籽油 - 卵清蛋白乳液凝胶的物理化学性质、微观结构和蛋白质结构的影响及作用机制。与用NEM处理卵清蛋白底物溶液（N - OSS）的卵清蛋白乳液凝胶相比，用NEM处理卵清蛋白乳液（N - OE）的卵清蛋白乳液凝胶具有更低的硬度、游离巯基含量、持水能力（WHC）和表面疏水性，但具有更高的自旋 - 自旋弛豫时间（T）。此外，与未用NEM处理的卵清蛋白乳液凝胶（对照组）相比，N - OE和N - OSS具有更低的硬度、游离巯基含量、WHC和表面疏水性，以及更粗糙和无序的微观结构。随着NEM浓度升高，卵清蛋白乳液凝胶的游离巯基含量、硬度、WHC和表面疏水性均降低（p < 0.05），而酰胺A带向更高波数变化。这些结果共同表明，界面层与蛋白质之间二硫键的减少抑制了疏水作用、氢键的形成，并阻止了更大聚集体的形成。因此，界面蛋白之间的二硫键有助于卵清蛋白凝胶硬度的提高和水分的稳定。
