Effect of pressure on moisture transfer during moisture adsorption

A set of coupled heat, mass, and pressure transfer equations was used to describe the moisture adsorption process in grain kernels. The finite element method was used to solve the system of equations. The technique was applied to analyze the temperature moisture, and pressure distribution in a barley kernel during soaking with steep water. The temperature and moisture distributions with (heat, mass, and pressure transfer model) and without (heat and mass transfer) the effect of pressure were simulated for assumed conditions. The results obtained from the heat, mass, and pressure transfer model show a marked difference from the results obtained from the heat and mass transfer model. This indicated that a pressure gradient exists during the transfer process, causing additional moisture movement due to filtration effect Hence, the pressure term cannot be assumed constant during the moisture adsorption process. The simulated temperature, moisture and pressure profiles and gradients can be used for determining the optimum time required for soaking kernels with steep water to produce barley malt.