Shrinkage of dates (Phoenix dactilyfera L.) during drying

In this paper the shrinkage of Dates (Phoenix dactilyfera L.) during drying was observed. Samples were dried in a convective tray dryer under three different conditions (60 degrees C-11.1%RH, 70 degrees C-7.2%RH and 80 degrees C-4.7%RH) and three different air velocities (0.5m/s, 1.0m/s and 1.5m/s). Sample shrinkage was directly (using a caliper) and indirectly measured (snapshot area measured). The indirect manner shows a higher precision. The geometry applied in the shrinkage solution proved that the ellipsoidal geometry of the dates, may be successfully approached to a cylinder. Three mathematical models developed by Suzuki et al. (1976) were applied to correlate the dates surface to its moisture content. The core model presented the best fit to the experimental data.