5 research outputs found
Retardation Mechanism of Crystallization of Diacylglycerols Resulting from the Addition of Polyglycerol Fatty Acid Esters
Edible
oils containing high concentrations (>80%) of diacylglycerols
(DAG oil) have beneficial health effects on obesity and obesity-related
diseases; however, at low temperature, undesired precipitation of
high-melting fractions in DAG oil can occur. Thus, preventing the
precipitation of high-melting saturated fatty acid moieties in DAG
oil is crucial for its expanded use. In this study, we investigated
the mechanism of retardation of crystallization of DAG oil through
the addition of polyglycerol fatty acid esters (PGFEs). We observed
the occurrence of birefringence under polarized crossed-Nicols conditions
in the PGFE-added DAG oil. We also found that prior to the crystallization
of high-melting DAG fractions, PGFE-added DAG oil showed shear-rate-dependent
changes in viscosity, providing strong evidence for the existence
of self-assembled structures that lead to the birefringence. Furthermore,
small- and wide-angle X-ray diffraction patterns suggest the formation
of a supramolecular assembly comprising DAGs and PGFEs, which is significantly
different from the structure of DAG crystals. From these results,
we conclude that the retardation of crystallization of DAG oil is
caused by the formation of liquid-crystal-like supramolecular complex
structures that contain high-melting fractions of DAGs and PGFEs.
These complexes may disturb the formation of critical nuclei of high-melting
DAG fractions during the prenucleation crystallization stage