The Effect of Cooling Rate on the Microstructure and Macroscopic Properties of Rice Bran Wax Oleogels

Abstract

The main purpose of this paper is to study the microstructure and macroscopic characteristics of rice bran wax (RBW) oleogels at a cooling rate of 1°C/min and 10°C/min by polarized light microscopy, X-ray diffraction, differential scanning calorimetry, texture analyzer, and micro rheometer. The oleogels of soybean oil were prepared by RBW in concentrations of 5%, 7.5%, 10%, 15% and 20% (wt/wt). The results of this study indicated that the concentration of RBW and cooling rates were affected by the crystal size and spatial distribution of these crystals. For the same RBW concentration, oleogels contained smaller crystals when cooled at 10°C/min compared to 1°C/min. And the oleogels obtained at a rate of 10°C/min exhibited a tighter crystal network, lower melting point, harder texture, and energy storage modulus. These results demonstrated the impact of cooling rate on the rheological behavior, nucleation, and crystallization process.