Extraction of sugars from forced chicory roots

The extraction of fructan and sugars from chicory roots is promising with regard to the production of 5-hydroxymethylfurfural. In this study, the extraction of chicory roots after the salad production was investigated for the first time in order to determine the extraction kinetics. Chicory roots were cut into different shapes (juliennes, slices, and cubes) and were extracted at different temperatures (T = 65 °C; T = 80 °C; T = 90 °C) and with different solid-to-liquid ratios (1:5; 1:10; 1:20) in batch experiments. Maximum extraction yields (90.15% of extracted sugars) were achieved for T = 80 °C and chicory roots that were cut into julienne shape. A solid-to-liquid ratio of 1:10 should be maintained in order to keep the process economical. Regarding the subsequent use of the extract for 5-hydroxymethylfurfural production, 89.5% of initial fructose and 89.8% of initial fructan were extracted at 80 °C. According to this, the sugar-containing extracts could be used in the future in decentralized biorefineries to produce 5-hydroxymethylfurfural directly from chicory roots as an agricultural residue.