Safety uncertain was always a problem related to the Maillard reaction in heat treatment at a presence of carbohydrate. Early researches have detected caramel color contains 5-hydroxymethyl-2-furaldehyde which is toxic and should be removed from caramel color as much as possible. In the present paper, the effects of ultrafiltration on reducing 5-hydroxymethyl-2-furaldehyde in caramel color solutions were investigated. Results showed that 5-hydroxymethyl-2-furaldehyde could be filtered through 10 kDa cutoff membrane absolutely, while, the retentate's browning intensity was increased significantly. All data show that ultrafiltration is an effective means to reduce 5-hydroxymethyl-2-furaldehyde content and increase browning intensity of caramel color solutions, which might be used in producing healthier caramel colors. (C) 2011 Elsevier B.V. All rights reserved.