Oil mobility in sucrose-in-oil dispersions as a function of particle morphology and BET surface

Solid particles in dispersions, for example sucrose, can reduce the mobility of liquid oils, potentially through sorption or physical entrapment. So far, little is known about the mechanisms and influencing factors behind oil immobilization. Fatty acid composition of oils and the sucrose characteristics (particle size, morphology, BET surface) are thought to affect oil immobilization in sucrose-in-oil dispersions. For this purpose, dispersions were prepared using four refined oils (coconut, peanut, rapeseed and sunflower oil) and four sucroses (powdered sucrose, granular fine and coarse sucrose and cotton candy). The oils varied in their fatty acid composition, viscosity, and diffusion coefficient, while the sucrose samples differed in their BET surface, particle size, and morphology. To investigate the influence of these properties on oil immobilization, the sucrose-in-oil dispersions were examined across different length scales using oil binding capacity, flow behavior, viscosity and wettability (macroscopic scale), as well as oil diffusion (molecular scale). Oil immobilization in sucrose-in-oil dispersions was affected stronger by the sucrose properties, especially their morphology and BET surface, than by the oil properties. On a macroscopic level, cotton candy showed the highest oil immobilization, followed by powdered sucrose. On a molecular level, oil diffusion was hindered most by powdered sucrose, while the geometric hindrance was smallest in dispersions with cotton candy.