Cinéticas de deshidratación osmótica de pitahaya amarilla (Selenicereus megalanthus)

The kinetics of osmotic dehydration was evaluated in slices of yellow pitahaya fruit at atmospheric pressure and under vacuum pulse application, using two concentrations of sucrose solution, of 55 and 65°Brix, for 4h at 30°C. The kinetics values were assessed in terms of water loss (ΔM_A) and solid gain (ΔM_S), and the Magee model kinetic parameters (KA and K_S, k_so and kA _o), the index of effectiveness (ΔM_A/ΔM _S) and the effective diffusion coefficients (De) were also evaluated. No significant differences in ΔM_A were evident at the end of the osmotic process as the effect of pressure, but differences were found as a result of the solute concentration of the osmotic solution. The diffusion coefficient was mainly influenced by concentration, confirming that the diffusive phenomena, rather that the hydrodynamic mechanism, favors the osmotic dehydration process.