Abstract: In this study, composite organogels containing sunflower seed oil were prepared with oryzanol/sitosterol and monoglycerides as gelators. The formation process of organogels and the influence of monoglycerides on the gelation process were examined. It was found that this process could be divided into three stages. Monoglycerides had little influence on the supercooling and supersaturatation stages. In the logarithmic stage of aggregation nucleation of gelators, monoglycerides could increase the enthalpy per unit volume and reduce the total Gibbs free energy, consequently promoting nucleation. In the linear stage of crystal growth and assembly, the primary, secondary and tertiary structures of organogels were gradually formed; the tertiary structure was most closely related to macroscopic properties and its ratio of permanent crosslinking to instantaneous crosslinking determined the main properties of organogels. Nuclear magnetic resonance analysis showed that the gelation process was mainly ascribed to physical entrapment. Furthermore, X-ray diffraction and small angle X-ray scattering were used to analyze the assembly structure and the results showed that a symmetrical hexagonal structure was found in oryzanol/sitosterol organogels, a symmetric layered structure in monoglycerides organogels, and composite organogels containing oryzanol/sitosterol and monoglycerides had a symmetric cubic structure.

Key words: monoglyceride, oryzanol, sitosterol, organogels, property, mechanism