Pickering emulsion gels stabilized by sardine protein/konjac glucomannan complexes delivering astaxanthin for alleviating inflammatory bowel disease.

Astaxanthin (AXT) alleviates inflammatory bowel disease (IBD) by reducing inflammation, blocking NF-κB pathway, and modulating gut microbiota. However, the poor solubility and low bioavailability of AXT limit its applications in food. In this study, sardine protein (SDP)/konjac glucomannan (KGM)-stabilized Pickering emulsion gels (SKEGs) were developed for AXT delivery for IBD intervention. Initially, the primary interactions between SDP and KGM were identified as hydrogen bonding and hydrophobic interactions. The addition of KGM effectively enhanced the interfacial adsorption capacity and wettability of SDP. Notably, at a KGM concentration of 1.2 %, the formed Pickering emulsion exhibited a more uniform and denser microstructure, with an oil droplet size of 7.12 ± 0.14 μm. Furthermore, the incorporation of konjac glucomannan (KGM) significantly improved the emulsion stability under the conditions of high temperature, high ionic strength and long-term storage. After 14 h of ultraviolet irradiation and heating, the retention rate of AXT in SKEGs was markedly higher than that of free AXT. Simulated digestion experiments revealed that SKEGs improved the bioavailability of AXT by reducing the release of AXT in stomach. In vivo mouse experiments demonstrated that the AXT-loaded SKEGs effectively alleviated weight loss and colon shortening induced by dextran sodium sulfate, and protected the integrity of colon tissue by regulating inflammatory factor levels s and restoring the expression of tight junction proteins including ZO-1 and occludin. Additionally, the AXT-loaded SKEGs restored the gut microbiota composition in IBD mice by reducing harmful bacteria and enriching beneficial species. This study presented a novel strategy for improving the biological accessibility of AXT in functional food formulations, simultaneously facilitating the efficient utilization of ocean resources.