Identification of Colored Components Produced in Sugar Beet Processing Using Gel-Permeation Chromatography (GPC) with UV and RI Detection

Sugar juices in the production of beet sugar contain complex varieties of colored materials that have not been identified completely. Color of the sugar depends the color of juices from which sugar is produced. The mechanisms concerning color formation in beet sugar processing are complicated due to many parameters involved. The main mechanisms related to the color formation during purification stage are the Maillard reaction and alkaline degradation of invert sugars, but caramelization is more important in thick juices. In this study, gel-permeation chromatography (GPC) is used to separate and determine some color components in raw, thin and thick sugar beet juices. Subsequently, the separate components are detected by a UV coupled to a refractive index (RI) detector in series. GPC is a suitable technique for determining the molecular weight distribution of compounds in juices and can be used to demonstrate colored compounds through the sugar beet processing. GPC chromatography, using UV and RI as detector, is the analytical method proposed to study the nature of colored impurities and to characterize the stages of the process where colorants are generated. The results show that all of the juices in this study had low molecular weight colorant in the range of 0.2 up to 10 kDa.