Coupling mechanisms dehydration and shrinkage of Spirulina platensis<< Arthrospiraplatensis >> during isothermal drying

The experimental study of monitoring of the volume variation of a cylinder of Spirulina platensis during isothermal drying at 50 degree C and HR =6% is discussed. Experimental characterization and biphasic modeling applied to samples from Burkina Faso and France show that their volume shrinkage is nonlinear. From the comparison of experimental and theoretical results, it appears that w =1,8kg sub( w)/kg sub( ms) is a water content limit of the saturation of the two samples. They pass to a regime triphasic where of the gaseous cavities appear gradually and prevents shrinkage under the dehydration effect. The experimental data of the volume variation are approximated by exponential function and used to determine the hydric expansion coefficient of each stump of Spirulina.