Nutraceutical Loaded Hydrogels with Enhanced Water Retention for Functional Food Delivery

¹ Theophane Venard School of Food Biotechnology and Innovation, Assumption University, Bangkok 10240, Thailand
² Laboratory of Organic Synthesis, Chulabhorn Research Institute, Bangkok 10210, Thailand

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Developing sustainable biopolymer matrices is essential for advancing functional food innovation. This study optimizes composite hydrogels formulated from sodium alginate and silk cocoon extract by comparing aqueous and hydro-ethanolic extraction systems. A comparative analysis of methodologies for extracting silk cocoon bioactive compounds revealed that aqueous extraction yielded a superior profile to hydro-ethanolic methods. The aqueous extract achieved a protein concentration of 30.41 ± 1.54 mg/L and demonstrated a DPPH radical scavenging capacity of 32.91 ± 7.26%, linking the functional bioactivity performance to its specific phytochemical composition. The macro-structural performance of formulated hydrogels—plain hydrogel (PH) versus extract-loaded hydrogel (EH) was evaluated via swelling, syneresis, and cryo-stability assays. Network hydration behavior was sensitive to environmental pH; at neutral pH (7.0), extract-loaded variant (EH) exhibited a controlled expansion with a maximum swelling ratio of 67.85 ± 4.89%, lower than that of the plain hydrogel (PH). Syneresis analysis revealed a stabilized liquid-phase retention in EH formulation (57.23 ± 1.46%) compared to PH formulation (48.91 ± 15.10%) demonstrating superior stability against syneresis of EH. Following freeze-thaw cycles, both hydrogels exhibited high structural integrity, with recovery rates of 84.35 ± 3.94% and 97.68 ± 0.28% for EH and PH, respectively. These findings establish a scalable framework for the effective formulation of nutraceutical composite hydrogel with superior water retention, reduced syneresis, and enhanced cryo-stability, demonstrating the potential of aqueous extraction to boost nutritional density and shelf-stability in health-promoting food products.