Recovery of aroma compounds from tomato industry effluent using membrane-based solvent extraction

This work focuses on a non-destructive process for recovering valuable aromatic fractions from an odorous tomato industry aqueous effluent. Non-dispersive solvent extraction of four selected aroma compounds, chosen as key aroma, was, at first, carried out on very diluted model aqueous solutions. Mass transfers from water to n-hexane and from water to Miglyol (two solvents widely used in aromatic industry) were studied using a cross-flow designed hollow fibre membrane contactor. The influence of physico-chemical properties of the aroma compounds studied and the influence of the solvent viscosity on mass transfer are discussed. The results obtained with model solutions have been validated on the industrial process effluent.

Membrane-based solvent extraction of aroma compounds from an aqueous tomato process effluent was performed using hexane and miglyol as solvents. The controlling step of the mass transfer depends on the properties of aroma compounds, and on the solvent phase. For hydrophobic compounds and hexane as a solvent phase, the operation is limited by diffusion from the bulk aqueous feed phase to the membrane. Hence, it would be interesting to study other module configurations in order to improve hydrodynamic conditions in the feed phase. For hydrophobic compounds and miglyol as a solvent phase, mass transfer is limited by diffusion in the solvent filled pores of the membrane and overall mass transfer coefficients were lower than those obtained with hexane even if miglyol offered higher partition coefficients. Finally, membrane-based solvent extraction was applied to the effluent and the efficiency of the process was demonstrated.