Synergistic phase behaviors of phytosterols and phytosterol esters in
medium chain triglycerides
Abstract
Free phytosterols (PS) and phytosterol esters (PSE) usually coexist in
natural oils, which significantly affect the crystallization behavior of
oil. However, the phase behaviors of PS/PSE mixtures in oils and their
roles on the crystallization behavior of oil are still unclear. In this
study, the dissolution and crystallization behaviors of PS/PSE mixtures
in medium chain triglyceride (MCT) were studied, and the synergistic
mechanism of PS/PSE mixtures on the crystallization behaviors of MCT was
further clarified. The results showed that when the mass ratio of PS:
PSE was greater than 3: 7, PS/PSE mixtures recrystallized a new
urchin-like crystal structure, which was different from PS spherical or
PSE plate-like crystal structure, in MCT. The new urchin-like PS/PSE
crystal 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 ºC higher than that of virgin MCT,
2.5 ºC higher than that of PSE/MCT, and 10.3 ºC higher than that of
PS/MCT. These results not only provide a method for obtaining new
crystal structure of phytosterols, but also have great significance for
controlling the crystallization behaviors of oils by precisely adjusting
the nutritional composition of oils.