2.6.2. Purification of FOS

Ethanol present in the supernatant phases of alcohol precipitation in the Section 2.6.1 was removed by rotary evaporation. The FOS mixture was then purified by active carbon adsorption chromatography to remove glucose, fructose, and sucrose [19]. The chromatographic column was filled with treated activated carbon, and the column volume was 200mL. After loading the sample of 20 mL (flow rate of 1 mL/min), we let it stand for 1 h and balanced the column with purified water. The amount used was 2 column volume. Elution with 5%, 10%, 15%, 20%, and 30% concentrations and pure ethanol at a 1 mL/min flow rate was carried out. We collected one tube every 10 mL and performed determination of FOS content. The purified FOSs with high purity were then freeze-dried for 48 h.
