Cristalizacion

IMPURITY EFFECTS ON COLOUR ADSORPTION
956 SUCROSE CRYSTALLIZATION - IMPURITY EFFECTS ON COLOUR ADSORPTION
A. Ferreira1, P. M. Martins, F. Rocha, Universidade do Porto, Portugal; N. Faria, BIOTEMPO,Portugal; S. Polanco, P. Rein, Audubon Sugar Institute, St. Gabriel LA, USA
Crystallization rates are affected by many variables such as temperature, agitation velocity, supersaturation, size andshape of crystals, impurity nature and concentration. The effect of impurities in the crystallization processes has been widely studied. According to their physical and chemical characteristics,impurities can have a stronger or weaker impact on the growth rates. Some impurities act on the properties of the solutions while others can also affect the mechanism of growth at the crystal surface.
Inthe present work the effects of starch, D-fructose and dextran on sucrose crystallization were investigated. For that purpose, a pilot vacuum pan at the Audubon Sugar Institute was used. The impurityeffects on colour formation during the crystallization process and on colour adsorption into crystals were also studied.
According to the experimental results, the crystal growth rates decrease as theimpurity concentration increases. Starch seems to have a greater influence on the growth rates.
Starch and dextran increase the colour formation during the crystallization process. The results alsoshow that D-fructose decreases both colour formation during the crystallization and colour adsorption onto the crystals. On the contrary, dextran seems to increase colour adsorption at the crystalsurface and colour inclusion into the crystal lattice.

EFECTOS DE COLOR IMPUREZAS ADSORCIÓN
956 SACAROSA cristalización - EFECTOS DE COLOR IMPUREZAS ADSORCIÓN
A. Ferreira 1, Martins PM, F. Rocha,Universidade do Porto, Portugal, N. Faria, BIOTEMPO, Portugal, S. Polanco, P. Rein, Audubon Sugar Institute, San Gabriel LA, EE.UU.
Las tasas de cristalización se ven afectados por muchas variables...