Sodium alginate-based wall materials microencapsulated Lactobacillus plantarum CICC 20022: characteristics and survivability study

In this study, microcapsules of Lactobacillus plantarum CICC 20022 (L. plantarum CICC 20022) were prepared by extrusion technique using sodium alginate (SA), sodium alginate-sodium caseinate (SA-SC) and sodium alginate-whey protein isolate (SA-WPI) as wall materials, respectively. Results showed that the best encapsulation yield of L. plantarum CICC 20022 was SA-WPI. Morphology and texture analysis showed that the microcapsules prepared by the SA-WPI system presented a more compact internal structure and higher resistance to external pressure. Fourier-transform infrared spectroscopy and low field nuclear magnetic resonance analysis demonstrated that the hydrogen bonding ability and network structure of the SA were improved by the addition of WPI. The survivability of L. plantarum CICC 20022 entrapped with the SA-WPI system was improved during freeze-drying and simulated gastrointestinal digestion. Therefore, the SA-WPI system can potentially be used as the vector of L. plantarum CICC 20022 in food applications.