Our project aims at developing a biorefinery integrated in the recycling line of paperboard, where starch would be separated from recovered fibers prior to the production of recycled paperboard. The extracted starch could then be valorized, which requires its characterization. Corrugated board made from recycled fibers was re-dispersed in water and filtered. Almost 100% of the starch initially present in the corrugated board was found in the filtrate. Asymmetric Flow Field-Flow Fractionation (A4F) coupled with multi-angle light scattering and differential refractive index detection was used to measure the molecular weight distribution of the extracted starch. This starch was welded by ultrasonic compression and the rigidity of the resulting structure was compared to commercial starches. Overall, this "recycled starch" showed promising results.