Yan Guosen, Li Yang, Wang Shiran, Li Yan, Zhang Liebing, Yan Jianguo, Sun Yanfang
Beijing Engineering and Technology Research Centre of Food Additives, School of Food and Health, Beijing Technology and Business University, Beijing 100048, China.
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
Food Chem X. 2024 Aug 26;23:101784. doi: 10.1016/j.fochx.2024.101784. eCollection 2024 Oct 30.
This study aimed to investigate the interfacial behaviour of caseins in different micelle content and its effect on the stability of emulsions, including micellar casein concentrate (MCN), calcium caseinate (CaC) and sodium caseinate (NaC). Results revealed that at high protein concentrations (0.5 %-2.5 %), MCN, CaC and NaC exhibited similar interfacial behaviour as well as unfolding rate constants ( ) of 3.11-3.41 × 10 (s), 2.96-3.35 × 10 (s) and 2.75-3.27 × 10 (s), respectively. The interfacial layer formed was dominated by non-micelles, and microscopic images revealed the thickness of the interfacial layer to be 10-20 nm. By contrast, at low concentrations, the differences in the slope of E-π curves and indicated that the micelle content of casein affects protein interfacial behaviour and properties and that micellar casein is involved in the formation of the interfacial layer. The formation of large numbers of droplets during emulsion preparation results in a similar low concentration environment. Cryo-TEM showed adsorption of micellar casein in all three casein-stabilised emulsions, and the amount of adsorption was proportional to the micelle content. NaC has faster adsorption and rearrangement rates due to fewer micelles and more non-micelles, so that NaC forms smaller droplets and more stable emulsions than those formed by MCN and CaC within the range of 0.5 % to 2.0 %.
本研究旨在探究不同胶束含量的酪蛋白的界面行为及其对乳液稳定性的影响，其中包括胶束酪蛋白浓缩物（MCN）、酪蛋白钙（CaC）和酪蛋白钠（NaC）。结果显示，在高蛋白浓度（0.5%-2.5%）下，MCN、CaC和NaC表现出相似的界面行为，其展开速率常数（）分别为3.11-3.41×10（s）、2.96-3.35×10（s）和2.75-3.27×10（s）。形成的界面层以非胶束为主，显微镜图像显示界面层厚度为10-20纳米。相比之下，在低浓度下，E-π曲线斜率和的差异表明酪蛋白的胶束含量会影响蛋白质的界面行为和性质，且胶束酪蛋白参与了界面层的形成。乳液制备过程中大量液滴的形成导致了类似的低浓度环境。冷冻透射电子显微镜显示，在所有三种酪蛋白稳定的乳液中都有胶束酪蛋白的吸附，且吸附量与胶束含量成正比。由于胶束较少且非胶束较多，NaC具有更快的吸附和重排速率，因此在0.5%至2.0%的范围内，NaC形成的液滴比MCN和CaC形成的更小，乳液也更稳定。
