MODELING AND ANALYSIS OF ULTRAFILTRATION EFFECTS ON THE QUALITY OF FRESHLY SQUEEZED ORANGE JUICE

Crossflow ultrafiltration by tubular PVDF membranes (MWCO=1.8.10(4)) w as studied for clarification and debittering of orange juice. The effe cts of the separation processes on the distribution of aroma compounds between permeate and fresh juice, were investigated. In particular th e limonin concentration in the permeate was reduced of about 65% with respect to the fresh juice. In addition, most of the more water solubl e compounds passed through the membrane. Hydrocarbons and less polar a roma compounds, remained mainly in the retentate. A mathematical model of the ultrafiltration system is also presented. It describes the acc umulation of suspended particles on the membrane, accounting for back- diffusion transport mechanisms. The additional resistance of particles layer was evaluated by the Blake-Cozeny-equation. The theoretical pre dictions in terms of permeate flux as a function of time, resulted in a good agreement with the experimental data.