Synthetic polyelectrolytes in the clarification of stevia aqueous extract

Abstract

The extract of stevia leaves is usually dark which demands a clarification in order to be accepted by sweetener consumers. One of the using techniques is the decantation, which requires the use of effective products for best results. In the market, flocculant products are available, such as: NOVUS^TM CE2666 (cationic) and BETZDEARBORN^TMF11 (anionic). When these products are used at a certain level of concentration, satisfactory results of decantation and consequent clarification are provided. The aim of this paper was to compare the performance of the best polymers by removal percentage (color and turbidity) and by the decantation speed. A Jar Test device was used and the concentration of coagulant (aluminum sulfate) and of polyelectrolytes were varied, as well as pH at 8,0, 9,0 and 10,0. Calcium oxide was applied in this phase. The best condition was obtained when the anionic polyelectrolyte was used, reaching a turbidity removal of 97%.