Imura Tomohiro, Nakayama Mio, Taira Toshiaki, Sakai Hideki, Abe Masahiko, Kitamoto Dai
Research Institute for Innovation in Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST).
J Oleo Sci. 2015;64(2):183-9. doi: 10.5650/jos.ess14167. Epub 2014 Dec 4.
In this study, the effects of the degree of hydrolysis on the interfacial and emulsifying properties of soybean peptides were evaluated based on surface and interfacial tension, dynamic light scattering (DLS), and freeze-fracture transmission electron microscopy (FF-TEM) analyses. Of the five evaluated soybean peptides (SP95, SP87, SP75, SP49, and SP23), those with higher degrees of hydrolysis (SP95 and SP87) did not exhibit noticeable surface-active properties in water, whereas those with relatively low degrees of hydrolysis (SP75, SP49, and SP23) exhibited remarkable surface tension-lowering activity. The latter set (SP75, SP49, and SP23) also formed giant associates with average sizes ranging from 64.5 nm to 82.6 nm above their critical association concentration (CAC). Moreover, SP23 with the lowest degree of hydrolysis exhibited excellent emulsifying activity for soybean oil, and FF-TEM analysis demonstrated that the emulsions were stabilized by a lamella-like multilayer peptide structure on the oil droplets that prevented coagulation. The peptide with the lowest degree of hydrolysis (SP23) was effective not only for soybean oil emulsification, but also for the emulsification of liquid paraffin and silicon oil that are generally difficult to emulsify.
在本研究中，基于表面和界面张力、动态光散射（DLS）以及冷冻断裂透射电子显微镜（FF-TEM）分析，评估了水解程度对大豆肽界面和乳化性能的影响。在评估的五种大豆肽（SP95、SP87、SP75、SP49和SP23）中，水解程度较高的大豆肽（SP95和SP87）在水中未表现出明显的表面活性，而水解程度相对较低的大豆肽（SP75、SP49和SP23）则表现出显著的表面张力降低活性。后者（SP75、SP49和SP23）在其临界缔合浓度（CAC）以上还形成了平均尺寸范围为64.5纳米至82.6纳米的巨大缔合体。此外，水解程度最低的SP23对大豆油表现出优异的乳化活性，FF-TEM分析表明，乳液通过油滴上的层状多层肽结构得以稳定，从而防止了凝聚。水解程度最低的肽（SP23）不仅对大豆油乳化有效，而且对通常难以乳化的液体石蜡和硅油乳化也有效。
