Embedding probiotic bacteria into the edible films: antibacterial activity and survival in simulated gastrointestinal condition

This study aimed to investigate the effect of incorporation of Lactobacillus plantarum on morphology, physical, mechanical and antimicrobial properties of anionic polysaccharide (alginate and pectin) films. Moreover, the viability of embedded L. plantarum was determined during film storage at 4 and 25 °C and passage through the simulated conditions of the digestive system. The addition of L. plantarum in polysaccharide films was able to modify their mechanical characteristics. The viability of L. plantarum in alginate was higher than the pectin film at 4 °C. The antimicrobial activity of films in broth medium depended on film composition and temperature. The most reduction of cell counts for Escherichia coli (2.55 log CFU mL−1) and Listeria monocytogenes (2.09 log CFU mL−1) at 25 °C were achieved in presence of probiotic alginate film. The embedding of bacterial cells in the film matrix could improve cell protective effect during digestion conditions in comparison with the free-form of bacteria. The results indicated that viable counts of L. plantarum only was decreased 0.51 log CFU mL−1 in alginate film during transmit of gastrointestinal simulation passage. Therefore, alginate film can be proposed in the design of food packaging with the probiotic and inhibitory properties.