4. Diffusion juice purification

There are several reasons why diffusion juice needs to be purified before concentration and crystallization:

• diffusion juice is black, grayish and opalescent. It contains suspended particles to which flakes of coagulated protein matter adhere, and it is difficult to filter these particles as they stick to the filters and the filtered juice would not be clear;

• diffusion juice is acidic (pH 5.6) and heating by evaporation would lead to sucrose hydrolysis with the production of reducing sugars (see figure 2 ), which in turn degrade to form colouring matter;

• In addition, the juice...