Valorisation of olive oil cake by extraction of hemicelluloses

Abstract

The Algerian olive residue contains about 30% of hemicelluloses, approximately 70% of which are uronoxylanes. These compounds are directly extracted by NaOH aqueous solution. Influence of various parameters such as temperature, NaOH concentration, solid/solvent ratio, size of solid particles, agitation, pre-treatment with KOH and extraction duration on the extraction yield has been investigated. An appropriate design of experiments was used and an optimal solution was found using the simplex method. The optimal values of parameters were: NaOH concentration 5.5%, and temperature 55 °C for an extraction duration of one hour . The kinetic study permits to determine the diffusion coefficient variation with temperature. Its values varies between 2.46 and 8.48 × 10 −11 m 2/s .