Production of colorless liquid sugar by ultrafiltration coupled with ion exchange

•The performance of UF membranes for liquid sugar decolorization was studied.•The effect of process conditions on UF performance was investigated.•The performance of ion exchange (IE) for liquid sugar decolorization was studied.•The process configurations of combining UF and IE for liquid sugar decolorization was evaluated.•The UF–IE configuration was the best process for liquid sugar decolorization.

Liquid sugar is an alternative product to crystal sugar, which is currently being considered by many sugar companies. However, production of colorless liquid sugar is still a big challenge. This work aimed to study the performance of ultrafiltration membrane and ion exchange (IE) both as single and integrated processes for decoloring cane sugar solution. The experiments were performed by using 10, 20, 50, and 100 kDa commercial UF membranes. Two commercial resins were used in ion exchange experiments. The results of decoloring sugar solution using UF membranes showed that the 20 kDa UF membrane made of polysulfone displays the best performance in term of flux and color removal. Integrating ion exchange process into UF membrane improves the color reduction resulting colorless liquid sugar. The UF–IE configuration shows a better performance than both the IE–UF and UF/IE alone configurations. These results provide important information about technologies that should be used for liquid sugar production.