Engineering fully biomass-derived foams as an alternative to plastic superabsorbents

This study explores potato protein juice as an unrefined industrial side stream integrated directly into hydrogel-derived foams, systematically compares two types of cellulose nanofibers (bacterial and TEMPO-oxidized) to tune pore structure and absorption behavior, and establishes relationships between gel rheology, freeze-dried pore architecture, density, and absorption performance as an alternative to lightweight synthetic high-performance bio-based absorbent foams. Here, the hydrogels that include the protein phase exhibit higher viscosity and thermal stability compared to those systems not including protein, with gelation occurring between 45 and 65 °C. Moreover, increasing polysaccharide content yielded denser structures with fewer pores and reduced absorption capacity. In contrast, freeze-dried formulations containing water, agar, and cellulose nanofibers displayed markedly higher absorption in 0.9 wt% saline solution (commercial standard to simulate urine) than commercial synthetic benchmarks, with comparable trends observed for blood uptake. These results demonstrate that polysaccharide–protein hybrid systems can deliver competitive absorption performance compared to synthetic counterparts while remaining biodegradable and free of microplastics, underscoring their potential for more sustainable single-use hygiene and sanitary items.