Free phytosterols (PS) and phytosterol esters (PSE) usually coexist in natural edible oils, which affect the crystallization behaviors of oil significantly. However, the phase behaviors of PS and PSE in oils and their roles on the crystallization behaviors of oil are still unclear. In this study, the isolation and dissolution behaviors of PS and PSE in medium chain triglyceride (MCT) were studied, and then their influences on the crystallization behaviors of MCT were clarified further. The results showed that when the mass ratio of PS:PSE was greater than 3:7 at the total amount of PS and PSE fixing 5 wt%, PS and PSE isolated to form a new crystal structure, which was different from PS spherical or PSE plate-like crystal structure, in MCT. The new PS/PSE crystal structure had a larger surface area, and its melting point was between PS and PSE. It also showed the synergistic ability to promote the crystallization nucleation of MCT. When the total content of PS and PSE was 1 wt%, and the mass ratio of PS:PSE was 5:5, the crystallization peak temperature of PS/PSE/MCT was 12°C higher than that of virgin MCT, 2.5°C higher than that of PSE/MCT, and 10.3°C higher than that of PS/MCT.

中文翻译：

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中链甘油三酯中植物甾醇和植物甾醇酯的相行为和成核效应

天然食用油中通常共存游离植物甾醇（PS）和植物甾醇酯（PSE），对油的结晶行为有显着影响。然而，PS和PSE在油中的相行为及其对油结晶行为的作用仍不清楚。本研究研究了PS和PSE在中链甘油三酯(MCT)中的分离和溶解行为，进一步阐明了它们对MCT结晶行为的影响。结果表明,当PS:PSE质量比大于3:7时,PS和PSE总量固定为5 wt%时,PS和PSE分离形成新的晶体结构,与PS球形或PSE不同MCT 中的板状晶体结构。新的PS/PSE晶体结构具有更大的表面积，其熔点介于PS和PSE之间。它还显示出促进MCT结晶成核的协同能力。当PS和PSE总含量为1 wt%、PS:PSE质量比为5:5时,PS/PSE/MCT的结晶峰温度比原生MCT高12℃,2.5℃比PSE/MCT高，比PS/MCT高10.3℃。