How is inulin extracted?

Theinulin is a prebiotic fibre used as food by probiotic bacteria. It is often used as a food ingredient for its thickening and sweetening properties, as well as in certain nutritional supplements, but also in cosmetics. Indeed, it is sometimes used for its moisturising and softening properties on the skin.

In the industry, inulin is primarily extracted from plants such as dahlia tubers (Dahlia), Jerusalem artichoke (Helianthus tuberosus) and chicory (Cichorium intybus), due to their high inulin content, respectively 10 - 12%, 14 - 18% and 14.9 - 18.3% w/w (weight by weight). Inulin can also be obtained using roots of elecampane (Ínula helenium L.). Various methods exist to enhance the extraction of inulin.

Method No.1: Extraction of Inulin using hot water.

This is the most commonly used method for extracting inulin. Firstly, the roots, rhizomes and stems are washed, then ground. The raw materials are extracted twice with hot water at a temperature of 75°C. The resulting inulin extract is treated with 96% ethanol, followed by a precipitation of the inulin at a temperature below -16°C. Finally, the precipitate is washed with ethyl alcohol and dried at a temperature of 50°C.

• Advantages : It is an easy technique to perform, it does not require a lot of equipment, and is cost-effective.

• Drawbacks : The drawbacks of this method include the lengthy duration of the process, the low yield of inulin, and a high number of impurities in the final product.

Method No. 2: Enzyme-assisted inulin extraction.

This technique complements other traditional extraction methods. The plant raw material is mixed with an enzymatic solution containing specific enzymes, generally inulinase, which cleaves inulin into smaller, more soluble fragments. Other enzymes such as cellulases and hemicellulases are also used to hydrolyse the components of the plant cell wall, thereby enhancing the extraction of inulin from the plants.

• Benefits : The use of enzymes has the advantage of being environmentally friendly. Furthermore, it increases the yield of inulin and is quicker to carry out.

• Drawbacks : The cost of enzymes and production are quite high. Moreover, the fragmentation of inulin could potentially lead to a change in its effectiveness.

Method No. 3: Ultrasonically Assisted Inulin Extraction.

Another technique is ultrasound-assisted extraction. The raw material is placed in water. High-frequency ultrasonic waves are emitted into the solution using an ultrasonic generator. These waves agitate the solution, creating areas of high and low pressure that cause the formation and implosion of microscopic bubbles (cavitation). This phenomenon creates turbulence in the solution, which facilitates the release of the desired compounds from plant cells.

• Benefits : It increases the yield of inulin, and it allows for a reduction in the duration of the process.

• Drawbacks : The equipment can be expensive.

Method No. 4: Production of inulin through biotechnology.

Inulin can also be synthesised from sucrose using an inulosucrase generated by a bacterium Eschereschia coli that has been modified. The produced inulosucrase is used for the production of inulin by incubating the sucrose with the enzyme at 25°C and at a pH of 5.5 for 12 hours. This procedure has allowed for the production of high molecular weight inulin. Consequently, it is possible to proceed with an enzymatic breakdown by inulinase to reduce the molecular weight of the inulin to make it more soluble.

• Benefits : Sucrose is a widely available substance. Furthermore, the technique is easily achievable and the yield is high.

• Drawbacks : The necessary addition of a purification step using inulinase may increase the cost of the technique.

Fully biodegradable, theinulin contained in our cleansing gels is derived from chicory root.