Construction of carboxymethyl chitosan/oxidized Astragalus polysaccharide cross-linked gel microspheres in alginate system: Improving the tolerance and functional characteristics of Lactobacillus paracasei

The efficacy of oral probiotics is severely limited due to the low biological activity and poor stability. Adopting advanced packaging technology can effectively enhance the activity of probiotics in harsh environments. In this study, we prepared a gel microsphere using microprocessor-driven injection technology. In the Alginate (Alg)-Zn 2+ system, L. paracasei M11–7 (M11–7) was encapsulated using the oxidized astragalus polysaccharide (OGP) and carboxymethyl chitosan (CMCS), which enhanced its delivery in the gastrointestinal tract. The research results exhibited that the gel microspheres had a size of 0.687 mm and belonged to the category of microgels. The SEM image indicated that the gel microspheres had a dense surface structure, and the encapsulation efficiency of M11–7 reached 91.53 %. The simulated gastrointestinal digestion revealed that after treatment with gastric and intestinal fluids, the live rates of probiotics in gel microspheres reached 91.66 ± 2.35 % and 60.43 ± 2.35 %, respectively. The gel microspheres also had good storage stability and thermal stability. In the intervention of the SHR rat model, gel microspheres loaded with M11–7 can alleviate endothelial dysfunction by lowering blood pressure, inhibiting oxidative stress and restoring the balance of the intestinal microbiota. This study provides ideas for constructing a safe and efficient probiotic loading system and improving the high-value utilization of probiotics.