Preparation and characterisation of novel casein-gum Arabic composite microcapsules for targeted in vivo delivery of Lactiplantibacillus plantarum A3

Abstract The health benefits of probiotics in the body are predicated on their ability to remain viable in harsh gastrointestinal conditions and complex pathological microenvironments. Casein and gum Arabic (GA), with dual emulsifying and stabilising effects in colloidal systems. Therefore, the objective of this research was to develop a novel microcapsule to encapsulate Lactiplantibacillus plantarum A3 using casein and GA as wall materials to improve the survival of the bacteria during gastrointestinal digestion, storage and lyophilization. The casein and GA composite microcapsules were prepared and characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the microcapsules had stable morphology, uniform size and spherical shape. The results revealed that the encapsulation of microcapsules significantly improved the survival of L. plantarum A3 in gastrointestinal fluid environment (5.52 × 10 9 cfu/ml) and lyophilization treatment (6.25 × 10 9 cfu/ml). Furthermore, the microencapsulated L. plantarum A3 exhibited an improved ability to regulate intestinal microbiota by effectively increasing the relative abundance of Bacteroidetes , Proteobacteria and Actinobacteria and decreasing the relative abundance of Firmicutes in vivo . The findings of the study will help to design a lactic acid bacteria encapsulation system based on the gastrointestinal environment and provide a basis for the development of probiotic functional products.