Chitosan-Fe coating-based synbiotic microcapsule with gastric acid resistance and intestinal targeted release and preparation method thereof

A preparation method of a chitosan-Fe coating-based synbiotic microcapsule with gastric acid resistance and intestinal targeted release, comprising the following steps:

• S1, preparation of a mixed probiotic microbial inoculant:
• conducting culture on a probiotic microbial inoculant to a late logarithmic growth phase, collecting cells, washing the cells several times with a sterile physiological saline to remove a medium, suspending washed cells in the sterile physiological saline, and adjusting a concentration of the cells to 1*108 CFU/mL for later use;
• S2, preparation of a chitosan-Fe coating solution:
• adding 1 g to 5 g of chitosan to 100 mL to 500 mL of a sodium citrate buffer with a pH value of 4.0 to 5.5, adding 6 mg to 10 mg of FeSO4:(H2O)x, stirring at a room temperature for 1 h to 6 h, and conducting sterilization for later use;
• S3, preparation of a microcapsule:
• mixing 65 parts to 85 parts by weight of the mixed probiotic microbial inoculant obtained in step S1, 10 parts to 15 parts by weight of prebiotics, 1 part to 5 parts by weight of pectin, and 5 parts to 10 parts by weight of glycerin to obtain a core material;
• extruding the core material into a sterilized CaCl2 solution by an extrusion method and soaking for 30 min to 60 min, adding a soaked core material into the chitosan-Fe coating solution prepared in step S2 to conduct constant-temperature magnetic stirring for 1 h to 3 h, and washing and filtering to obtain the microcapsule;
• and
• S4, freeze-drying:
• freeze-drying the microcapsule obtained in step S3 to obtain the synbiotic microcapsule.