Hydraulic permeability of food tissues

Pressure driven flow can arise in a food process due to various reasons such as rapid internal evaporation in microwave heating of a food. Whether intended or unintended, pressure driven flow can be a very significant mode of transport of water, vapor, and other components. The physics of pressure driven flow cannot be lumped into effective diffusivity type formulation in general. Permeability, a material property that is needed to properly describe this physics of pressure driven flow using mechanistic models and is generally unavailable. For the first time, intrinsic permeability of potato and muscle tissues to water were measured by making water flow through the samples under pressure and measuring the flow rate in a dedicated commercial setup for measuring permeability. Intrinsic permeability values were found to be in the range of 10(-17) - 10(-19) m(2). Permeability of soft food materials change significantly with pressure, however, electron microscope pictures showed no change in structure in potato tissue.