Extraction, optimization, purification and characterization of inulin from chicory roots using conventional and...

Inulin is a natural polysaccharide that has abundant applications in the chemical, food, and pharmaceutical industries. In the present studies, extraction of inulin was attained using conventional techniques (Soxhlet) and green techniques (ultrasonication) from chicory roots. The extraction parameters were optimized using Box-Behnken design and response surface methodology (RSM). The parameters selected were ultrasonication temperature (40-80 °C), time duration (30-120 min), and solid-to-solvent ratio (1:10-1:40 g/mL). Distilled water was used as solvent. The optimal conditions for extracting inulin using the UAE method were solid-to-solvent ratio of 1:40 g/mL, 120 min, extraction temperature of 60 °C, to get maximum yield (64.79 %). For the Soxhlet apparatus method, these conditions were 1:40 g/mL, 6 h, 90 °C, and (59.1 %), respectively. LC-MS showed maximum purity (98 %) of inulin in the UAE method. FT-IR, ¹H NMR, and ¹³C NMR confirmed the inulin extraction. XRD analysis showed that inulin was mostly amorphous, while SEM showed rough surfaces with inulin aggregates of various sizes. The maximum DPPH radical scavenging activities were 68.89 %, 53.80 %, and 45.17 % for Stdin, Chuw, and Chsw, respectively. Overall, the UAE outperformed the conventional Soxhlet method in terms of efficiency and extraction time.