Tailoring polysaccharide-based aerogels for potential food applications: Structural and hydration characterization by...

Polysaccharide-based aerogels are promising candidates for food-related applications due to their high surface area, adjustable porosity, biocompatibility, and biodegradability. The present study investigated chitosan, sodium alginate, and xanthan gum aerogels obtained by supercritical CO₂ drying. Each polysaccharide exhibited unique structural and physicochemical behavior depending on polymer concentration, which influenced the final aerogel properties such as bulk density, pore size, surface area, and water absorption. NMR relaxometry and diffusometry were employed for a detailed characterization of pore structure, hydration behavior, and molecular mobility. Results revealed that, in contrast to alginate aerogels, lower polymer concentrations in chitosan led to more open networks with larger pores and higher surface areas, making them more suitable for applications such as filtration, adsorption, or active compound delivery. On the other hand, xanthan gum aerogels formed denser, more crosslinked structures, yielding high water absorption rate suitable for controlled release or encapsulation purposes. A hybrid chitosan/alginate aerogel successfully combined the advantageous properties of both components, resulting in low-density materials with enhanced porosity and mechanical integrity. The difference in aerogel structures obtained by different polysaccharides highlights the possibility of tailoring aerogel properties for specific food applications, from active packaging to edible carriers or moisture regulators. Given the need for safer, biodegradable, and versatile materials in the food industry, this study highlights the importance of designing aerogels based on the material type and offers a practical guide for producing them using scalable and safe methods.