Structural properties changes during osmotic drying of plantain (Musa paradisiaca AAB) and their role into mass transport

This work studies the structural properties of plantain (Musa paradisiaca AAB) during osmotic dehydration (OD) and its role in the phenomena of mass transfer. Drying temperatures of 40, 60 and 80°C and sucrose solutions of 29 and 45°Brix were used in OD. Apparent and true volume, were measured using volumetric displacement and gas stereopycnometer methods. Apparent (ρ_b) and true densities (ρ_p) were calculated with volume data. Porosity (ε) and shrinkage (S) were calculated based on ρ_b and ρ_p data. Apparent diffusion coefficient (D_aw) of water and solids (D_as) were calculated. Micrographs were obtained for both, raw and dehydrated samples. The major water loss (WL) was found at 45°Brix dehydrated at 40 and 60°C, whereas the major solid gain (SG) was obtained at 45°Brix dehydrated at 80°C. A non-linear volume dependence on loss moisture, as well as a ρ_p and ρ_b increase and ε reduction with two pseudo-equilibrium periods was found. Micrographs at different depths of the food tissue revealed the effect treatments on two structural anisotropy areas. Shrinkage, starch gelatinization and swelling, as well as anisotropy affect the mass transfer.