In vitro and in vivo study of sodium polyacrylate grafted alginate as microcapsule matrix for live probiotic delivery

• Edible semi-natural polymer (Alg-PAAs(1:2)) was synthesized and used for probiotic delivery in functional food.
• Alg-PAAs(1:2) improved the survival of probiotic in SGF, and the release into SIF and SCF in vitro.
• Alg-PAAs(1:2) enhanced the viability of probiotic reached ileum and colon in vivo.

In this work, the effect of extra carboxylate groups in alginate (Alg) matrix was studied for live probiotic microencapsulation. Edible semi-natural polymer was synthesized by grafting sodium polyacrylate (PAAs) from alginate to improve the acid-resistant property of Alg. Grafted (Alg-PAAs(1:2)) and natural Alg were used to encapsulate Lactobacillus plantarum MA2, and the protective effect was investigated in vitro and in vivo. The survival of L. plantarum MA2 was improved in Alg-PAAs(1:2) microcapsule by 1.41 log CFU/mL in stimulated gastric fluid, and the release was considerably enhanced in simulated intestinal and colonic fluid compared with that of Alg microcapsule. Furthermore, the results of animal tests demonstrated that MA2 encapsulated in Alg-PAAs(1:2) microcapsule survived better than that in Alg microcapsule both in small intestine (5.30 log CFU/mL) and large intestine (2.14 log CFU/mL) after 24 h. According to our research, Alg-PAAs(1:2) could be a potentially effective microcapsule matrix in probiotic delivery.