Preparation and Characterization of Lactobacillus plantarum CICC 20270 Microcapsules

Lactobacillus plantarum CICC 20270 mixed with coconut oil/corn oil as core material was added to the DE25/DE18 emulsion as wall material for the preparation of probiotic microcapsules by spray drying. The encapsulation efficiency,surface structure,heat resistance,storage stability and the survival rate in the simulated gastric and intestinal conditions of the microenapsulated strain were investigated. The results showed that the encapsulation efficiency of the prepared microcapsules were over 90%. Under 55℃ heat treatment conditions,there was no significant difference in the number of viable cells(p>0.05).After heat treatment for 1,10 min at 65℃,the lowest microbial activity was DE25/coconut oil and DE18/coconut oil microcapsules.The survival rates were 75.66% and 49.82%,respectively.After heat treatment at 75℃ for 1,10 min,the bacteria activity in DE18/coconut oil microcapsules was the lowest,which was 38.40% and 15.08%,respectively.The storage properties of corn oil microcapsules were more stable than those of coconut oil at storage conditions of 4,25,and 37℃.At 33%,52%,and 75% humidity conditions,the difference in the DE value of the syrup had a greater effect on the survival of the probiotic than the oil and the DE25 syrup provided better protection for the probiotic.In the 6 h in vitro simulated digestion,the bacteria activity of DE25 syrup/coconut oil microcapsules only decreased by 3.88 lg CFU/g.Therefore,DE25 syrup was more suitable as a wall material for probiotics. Adding corn oil made the microcapsules have better heat resistance and adding coconut oil was more conducive to increase the number of microcapsules in the simulated gastrointestinal fluid.