Production of polysaccharide-based aerogels and exploring their use in different food applications

Date

2025-8-29

Author

Namlı, Serap

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Aerogels obtained by drying hydrogels with supercritical CO2 drying are widely used as adsorbents, carrier systems, or catalysts owing to their highly mesoporous structure, high surface area and ultra-low bulk density. In this study, aerogels produced from chitosan, sodium alginate, xanthan gum, and chitosan-alginate hybrid using non-toxic methods and supercritical CO2 drying to preserve their porous structure. These aerogels were applied for the first time in two distinct food-related processes: iced tea clarification and enzyme immobilization. The effects of polymer type and concentration on aerogel properties were investigated through comprehensive characterization techniques. Additionally, the influence of deacetylation degree (DDA) and molecular weight (MW) of chitosan on aerogel structure was evaluated. For tea clarification, chitosan and xanthan gum aerogels were evaluated as bio-based alternatives to commercial silica for removing turbidity from ready-to-drink black and green iced teas. Their clarification performance was evaluated using both chemical analyses (e.g., total polyphenol content, protein concentration) and instrumental methods including Nuclear Magnetic Resonance (NMR) relaxometry and Fourier Transform Infrared Spectroscopy (FTIR). In the enzyme immobilization application, chitosan, alginate, and hybrid aerogels were used as supports for pectinase immobilization via physical adsorption, and their performance in multiple reuse cycles was evaluated. The immobilized enzymes were also used in apple juice clarification as a model system. Results showed that aerogel structure and functionality strongly depended on polymer characteristics. Chitosan aerogels achieved effective tea clarification with minimal loss of beneficial compounds. Hybrid-immobilized pectinase maintained high enzymatic activity after repeated cycles, demonstrating the potential of aerogels to improve process efficiency. Overall, these findings highlight bio-based aerogels as sustainable, versatile, and food-safe materials with the potential to replace conventional adsorbents and enzyme supports in food processing. Their renewable origin, tunable structure, and reusability make them promising candidates for diverse applications in the food industry.

Subject Keywords

Aerogel, Supercritical CO2 drying, Bio-adsorbents, Enzyme immobilization, Tea clarification

URI

https://hdl.handle.net/11511/116101

Collections

Graduate School of Natural and Applied Sciences, Thesis