Crystalline dextrose

Fig. 2. Production of crystalline dextrose (7), where ds is dry substance db, dry basis Dg, D-glucose and CPY, crystal-phase yield.

Total sugar products are also produced by dehydrating hydroly2ate to a mixture of crystals and amorphous glass. This product is not produced in significant quantities in the United States or Europe but is popular in Japan and Korea where it represents 40—50% of total crystalline dextrose sold (14). 

Analysis and Specifications. Typical product analyses include sohds level, ash, color, conductivity, purity, and minor saccharide levels (19). Specifications for anhydrous and monohydrate crystalline dextrose are available (15). High quahty anhydrous dextrose produced for the pharmaceutical industry is prepared in accordance with additional specifications (20). 

The carbohydrate chemist is familiar with the general aspects of the process for the manufacture of crystalline dextrose because of the important position this compound occupies in the whole carbohydrate field. The special features of the process, however, are less familiar and it is hoped that this discussion will afford a better idea of modern methods. 

More than a century elapsed between the discovery of the hydrolysis of starch and the successful large scale manufacture of crystalline dextrose of high purity. Examination of some less familiar properties of dextrose will indicate the difficulties which have been encountered in developing the processes used today. 

IV. Application of Ion Exchange Refining to the Commercial Manufacture of Crystalline Dextrose... 

Refining. After saccharification, the hydrolyzate is clarified by precoat filtration, or possibly membrane filtration, to remove traces of insoluble fat, protein, and starch. Treatment with powdered carbon, granular carbon, and/or ion-exchange resins is then used to remove residual trace impurities, color, and inorganic constituents. The refined hydrolyzate can be dried to a solid product, evaporated to a high dextrose syrup, or processed to crystalline monohydrate or anhydrous dextrose. A typical process for production of crystalline dextrose is shown in Figure 2(7). 

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