Preparation Of KGM-ALG Composite Probiotics Microcapsules And Evaluation Of Its Function

Probiotics can regulate the balance of intestinal flora and promote the digestion and absorption of nutrients,which are widely used in food and other fields.However,the destructive effect of gastric acid on probiotics,it is difficult to have enough live bacteria to reach the intestinal tract to play its role.In order to enhance the survival rate of probiotics in adverse environments,microencapsulation technology was used to embed probiotics.Konjac glucomannan(KGM)is a kind of natural high molecular polysaccharide,which has the function of regulating intestinal microorganisms.Therefore,in order to protect the activity of probiotics,konjac glucomannan and sodium alginate(ALG)were used as wall materials to prepare the composite probiotics microcapsules,which provided a theoretical basis for the industrialization of probiotics microcapsules.The main contents of this study are as follows:1.The Preparation technology and safety evaluation of composite probiotics microcapsules: The results showed that the mass fraction of KGM,the mass fraction of ALG,the water-oil volume ratio and the mass ratio of calcium carbonate to ALG had a great influence on the embedding rate.On this basis,the technological conditions of microcapsules preparation were obtained by orthogonal experimental design: the mass fraction of KGM was 0.6%,the mass fraction of ALG was 3%,the water-oil volume ratio was 1:3,the mass ratio of calcium carbonate to ALG was 1:3,and the embedding rate reached(76.2±5.1)%.The safety of the microcapsules prepared by the above-mentioned optimization process was evaluated by the feeding test of mice.The results showed that the microcapsules had no potential safety problems by detecting the biochemical indexes of serum and observing the histopathological sections.2.Apparent characteristics and in vitro performance evaluation of composite probiotics microcapsules: The average particle size of the microcapsules prepared under the above conditions was(352.6±9.5)?M,with a good spherical shape and a smooth surface.After freeze-drying,the microcapsule was observed by scanning electron microscopy,showing a honeycomb shape,surface folds and dents,and still maintaining a spherical appearance.The survival rate of the embedded probiotics was still(45.65±5.0)% after being treated in the gastric juice at p H 2 for 120 min.After treatment in intestinal juice for 60 minutes,the microcapsules were lysed,and probiotics could be effectively released in the intestinal tract.The number of live bacteria reached(9.35±0.25)Log cfu/g.In the simulated continuous gastrointestinal test,the number of live bacteria of the microencapsulated probiotics still reached(7.57±0.05)Log cfu/g.Microcapsules could not only improve the survival rate of probiotics in gastric juice,but also enhance the tolerance of probiotics to bile salts,and the number of live probiotics could still reach(7.7±0.3)Log cfu/g.3.The preventive effect of composite probiotics microcapsules on constipation mice: eighty BALB/c mice were randomly divided into 8 groups: the normal group,the control group,the phenolphthalein group,the probiotics powder group,the KGM-ALG composite probiotics microcapsules low-dose group,the KGM-ALG composite probiotics microcapsules medium-dose group,the KGM-ALG composite probiotics microcapsules high-dose group,and the ALG composite probiotics microcapsules group.After 14 days of continuous gavage,in addition to the normal group,mice were induced constipation by administration of loperamide.By measuring related constipation indexes(first defecation time,small intestine propulsion rate,etc.),it was found that the KGM-ALG composite probiotics microcapsules medium-dose group and the KGM-ALG composite probiotics microcapsules high-dose group had better effect on relieving constipation in mice.The first black defecation time was(149±10)min and(141±7)min,and the small intestine protraction rate was(62±2)% and(70±4)%,respectively.It was found that medium dose of KGM-ALG composite probiotics microcapsules can reduce the relative abundance of Odoribacter and Alistipes,increase the content of short chain fatty acids such as acetic acid and butyric acid in vivo,and effectively relieve constipation in mice.This study laid a foundation for the application of KGM-ALG composite probiotics microcapsules.