Convective drying of spirulina in thin layer

Spirulina is a microalgae with therapeutic and nutritional properties. It is now industrially produced and dried by spray drying into a powder. The drying method of small productions facilities in addition to a need for a different form of presentation, leads us to study the drying of spirulina by convection. In this study, spirulina sorption isotherm is established through different methods at 25 and 40 degreesC. The results vary slightly in function of the method but do not vary in function of the temperature. A simple Henderson model is proposed to represent the isotherm. The drying by convection is characterized by the kinetics experimental drying in order to study the influences of temperature and air velocity. Under conditions of temperature and air velocity of less than 40 degreesC-2.5 m/s, a first drying phase appears on the curves. By normalizing, the use of the drying characteristic curve allows the regrouping of curves and the representation of thin layer spirulina convective drying by a polynomial function. (C) 2004 Elsevier Ltd. All rights reserved.