Liquid imbibition during rehydration of dry porous foods.

摘要

Water imbibition theory has been shown to have a multidisciplinary validity. To demonstrate its applicability to the rehydration of dried porous food, kinetics of water uptake of freeze-dried (FD) carrots was studied. Water imbibition followed the general Lucas-Washburn equation. Utilizing different liquid media highlighted the need for model improvement overcoming several discrepancies mainly related to the utilization of a single "effective" cylindrical capillary and a constant contact angle. A significant swelling of the carrot samples was observed and quantified. The rate of lateral one-dimensional expansion of the samples was modeled assuming two first-order independent kinetic processes. These results indicated that dry foods could be treated as a composite "porous media", for which pertinent processes and variables should be taken into consideration.