Responses of Microencapsulated Lactiplantibacillus plantarum L3 Added in Yoghurt to Storage Environments

Fermented milk with water-in-oil-in-water (W/O/W) Lactiplantibacillus plantarum L3 microcapsules prepared with modified low methoxyl pectin (mLMP) and a commercial starter culture was stored 4 ℃ for 0, 7, 14 or 21 days prior to simulated gastrointestinal digestion. To investigate the stress response of L. plantarum L3 to fermentation, storage and simulated gastrointestinal environments, viable count was measured, cee morphology was observed, and the fatty acid composition of the cell membrane and intracellular amino acid composition were analyzed. Results showed that after storage for 21 days and simulated gastrointestinal digestion, the viable count was maintained at about 9.74 (lg(CFU/mL)) and the cell structure remained intact and clear. Alanine, glutamic acid and aspartic acid were the most abundant amino acids in microencapsulated L. plantarum L3 at all storage periods. The ratio of unsaturated to saturated fatty acids in the cell membrane increased firstly and then decreased with storage time, but was always higher than that of free L. plantarum L3. In conclusion, W/O/W microencapsulation can improve the survival rate of L. plantarum L3 in adverse environments such as yoghurt, cold storage, gastric acid, bile fluid and intestinal fluid, which provides a scientific basis for the application of functional strains in food carriers.