Effect of quality and origin of technical sucrose solutions on the inclusion of colourants into the sugar crystal matrix.

BACKGROUND: Due to the liberalisation of the European sugar market the pressure to improve factory utilisation is growing. Currently, beet and cane as sucrose sources are produced in isolation, according to geography. Co-production of sugar from beet and cane origin in one stream is a promising option. However, the knowledge base for production sugar is practically non-existent. This paper is part of our contribution to this field and specifically addresses effects of raw material quality.

RESULTS: This framework formulated for the colouring of sugars crystallised from mixed syrups is also valid for different raw material qualities: raw cane sugars: colour values 1221 to 2505 IU, dextran levels 50 to 1200 mg kg-1 ; beet syrups: 1509 to 2058 IU. Co-crystallisation is the main colour incorporation mechanism. Colour due to liquid inclusion increases strongly at cane inclusion levels in excess of 60%. The prediction of final sugar colour based on characteristics of pure mixture constituents is verified and indicates significant differences to current recommendations.

CONCLUSION: A first comprehensive description of the colour values in sugars produced from mixed cane and beet syrups is presented. Prediction of colour values from data on sugar colour of single sources marks a major contribution to future applications of co-production. © 2017 Society of Chemical Industry.