APPLICATION OF GAB OR OTHER MODELS FOR WATER SORPTION ISOTHERMS DETERMINATION OF TRADITIONAL BAKERY PRODUCTS

The vapour sorption isotherms of five typical baked foods were determined at 20 degrees C. In particular, the methodology proposed by Cost Projects 90 and 90 bis have been used. The latter procedure implies using a proper number of pieces of each product. The products have been closed in desiccators, in which nine different equilibrium relative (ERH) humidity have been created. The relative humidity inside desiccators have been checked daily until equilibrium, before placing samples. Moisture content of samples has been measured by a gravimetric method, while water activity has been determined by a dew-point hygrometer. All obtained data have been interpolated to fit the GAB equation or other equations and the mean relative percentage deviation modulus (E%) calculated.