The National Center for Precision Machining and Safety of Livestock and Poultry Products Joint Engineering Research Center, College of Food Science, South China Agricultural University, Guangzhou 510642, China; Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China.
The National Center for Precision Machining and Safety of Livestock and Poultry Products Joint Engineering Research Center, College of Food Science, South China Agricultural University, Guangzhou 510642, China.
Food Res Int. 2022 Oct;160:111668. doi: 10.1016/j.foodres.2022.111668. Epub 2022 Jul 11.
In this study, succinic anhydride (SA) and octenyl succinic anhydride (OSA) were used to modify the egg white protein (EWP), and acylated EWP was further prepared as a gel by adding NaOH and heat modification. The results showed that the acylation degree for the SA- and OSA-added groups reached 57.68% and 26.95%, respectively, and the average size, the absolute value of ζ-potential, increased significantly with SA and OSA addition, indicating that acylation improved the stability of EWP solution. Furthermore, the surface hydrophobicity increased for the SA-added group while decreasing for the OSA-added group, and the acylation process exposed the flexibility part of the protein molecule. Acylated EWP prepared gel (EWG) showed a translucent and slightly yellow appearance (except for the sol state of the OSA-added 1:50 group), the gel strength, water-holding capacity and rheological properties for SA-added EWG were remarkably reduced while OSA-added EWG improved apparently. Intermolecular forces analysis indicated that the addition of SA promoted the formation of disulfide bonds and strengthened proteins interactions while adding OSA weakened the interactions. Microstructural observations revealed a rougher gel network structure and weaker protein cross-linking in the gel prepared after the acylation of proteins. However, the high efficiency of SA and promotion of protein-molecule interactions were unable to counteract the negative effect of SA on the extension of the gel network structure, and the interaction between OSA expanded the formation of the gel network structure.
在本研究中，琥珀酸酐（SA）和辛烯基琥珀酸酐（OSA）被用于修饰蛋清蛋白（EWP），并且酰化的 EWP 通过添加 NaOH 和热改性进一步制备为凝胶。结果表明，SA 和 OSA 添加组的酰化度分别达到 57.68%和 26.95%，平均粒径和ζ-电位的绝对值显著增加，表明酰化提高了 EWP 溶液的稳定性。此外，SA 添加组的表面疏水性增加，而 OSA 添加组的表面疏水性降低，酰化过程暴露了蛋白质分子的柔性部分。酰化的 EWP 制备的凝胶（EWG）表现出半透明和略带黄色的外观（除了 OSA 添加 1:50 组的溶胶状态），SA 添加 EWG 的凝胶强度、持水能力和流变性能显著降低，而 OSA 添加 EWG 明显改善。分子间作用力分析表明，SA 的添加促进了二硫键的形成和蛋白质相互作用的增强，而 OSA 的添加则削弱了相互作用。微观结构观察表明，酰化蛋白质后制备的凝胶具有更粗糙的凝胶网络结构和较弱的蛋白质交联。然而，SA 的高效率和促进蛋白质分子相互作用的作用无法抵消 SA 对凝胶网络结构扩展的负面影响，OSA 的相互作用扩展了凝胶网络结构的形成。
