The effect of different porous media on moisture loss and oil absorption profiles during frying using glass micromodels

Abstract

Microstructure plays a key role in oil absorption during frying. The aim of this work was to improve our understanding of the relationship between microstructure and oil absorption, through the use of glass micromodels to obtain evidence of transport phenomena in three porous networks. Micromodels were saturated with water and partially immersed in oil at 190oC. Moisture and oil profiles were imaged to get water and oil saturation maps. Image and fractal analyses wereperformed to describe the morphology of the evaporation and oil fronts. Results showed that higher porosity facilitatedthe moisture removal and promoted greater oil absorption during cooling. The fractal dimension showed that microstructureswith a relatively high number of fine capillaries were less stable and propitiated fingering during the advance of the evaporation front. In all matrices, the disruption of the surface oil film due to air penetration was a critical factor to stop oil imbibition.