Storage of Cardoon Roots for Inulin Production

This work has been performed in the frame of COMETA Project. COMETA is a three-year project aimed at developing value chains based on low-input non-food crops suitable for marginal areas in order to convert all the crop fractions by advanced green chemistry technologies into bio-based products. Among the crops analyzed, particularly attention was put on Cardoon (Cynara cardunculus L.) since it is a multipurpose crop, suitable for low productive land and drought environments. In addition to the aboveground biomass (seeds, stalks, and leaves), COMETA Project has attempted to exploit the high content of inulin contained in the cardoon roots. While the industrial production of inulin relies on Chicory (Cichorium intybus L.) and Jerusalem artichoke (Helianthus tuberosus L.), the inulin contained in the roots of Cardoon is not yet exploited. However, in the perspective of the circular bioeconomy, the exploitation of the cardoon roots at the end of the crop cycle is an interesting option for biorefineries. In the industrial value chain, storage conditions are crucial in order to prevent inulin content as well as the dry matter content in the roots. The complete and partial drying of chipped roots before six-months period of storage has been evaluated for two years. The complete drying of roots allowed to preserve the inulin content up to six months of storage, while limiting the drying times, despite an energy saving, determined a significant loss of the retrievable inulin.