Rehydratable dry bacterial cellulose formulation and the role of sodium alginate in mitigating hornification

In this study, a cost-effective dry formulation of bacterial cellulose (BC) was developed by employing sodium alginate (SA) as a capping agent to reduce hornification during the drying process. The effects of different BC-to-SA ratios were assessed for reducing hornification and improving rehydration capabilities. The mechanism by which SA alleviated hornification in BC was explained at macroscopic, microscopic, and molecular levels. Compared with BC alone, the BC powder prepared with a 1:3 BC-to-SA ratio (BCSA3) demonstrated significantly better rehydration and redispersion capabilities, and a BC-to-SA ratio of 1:5 (BCSA5) exhibited the best rehydration performance. Sedimentation assay revealed that BCSA5 exhibited the lowest sedimentation ratio among the rehydrated formulations. Pore size distribution analysis indicated that SA effectively reduced the macropore volume of BC, preventing pore collapse during structural shrinkage. Furthermore, XRD and FTIR analyses confirmed that SA reduced hydrogen bonding in the amorphous regions of BC during drying, resulting in lower crystallinity. Rheological characterization of rehydrated samples further demonstrated the efficacy of SA in retaining functional properties. Compared with traditional freeze-drying, our findings revealed that formulating BC with SA at appropriate ratios could lead to rehydratable products via oven-drying, a more cost-effective and scalable approach for large-scale production and industrial applications.