Modeling of ultrasound assisted and osmotically induced diffusion in plant tissue
Abstract
The phenomena of osmotically induced diffusion in plant tissue placed in various sucrose solutions (0 to 60$\sp\circ$Brix) were studied. The effect of acoustic radiation on this type of diffusion was also investigated. When apple tissue was placed in low concentration of sucrose solutions ($<$17.5$\sp\circ$Brix), it absorbed water whereas it dehydrated in higher concentrations ($>$20$\sp\circ$Brix). Application of acoustic energy accelerated both the rate of water diffusing into and out of the tissue. The acceleration of the rate of water uptake was up to 10 times faster as compared to control samples at low concentrations. At high concentrations, the effect of sound was less pronounced. The water potential of the tissue was slightly reduced ($\approx$10%) in the presence of sound field. The behavior of a sound wave traveling through sugar solutions and plant tissue was experimentally analyzed, and linear relationships for sound attenuation in solution and plant tissue were developed. Mathematical models based on Fick's laws of diffusion and irreversible thermodynamics were developed to describe quantitatively the behavior of osmotically induced mass transfer in plant tissue with and without sound field. The acceleration of diffusion by sound was probably due to: (a) creation of acoustic streaming; (b) alteration of diffusion driving force; and (c) increase of mass transfer coefficient. The models were verified by comparing simulation results to experimental data.
Degree
Ph.D.
Advisors
Floros, Purdue University.
Subject Area
Food science
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