Evaluation of Lactobacillus plantarum encapsulated with Eleutherine americana oligosaccharide extract as food additive in yoghurt.

This study aimed to determine the survival and antibacterial activity of Lactobacillus plantarum TISTR1465 encapsulated with Eleutherine americana oligosaccharide extract. Capsules were stored at 4 °C for 0, 2, and 4 weeks. The encapsulated cells were evaluated for their survival after sequential exposure to simulated gastric and intestinal juices, then evaluated in terms of their antibacterial activity. Survival of the encapsulated cells was higher than that of free cells at weeks 2 and 4. Highest levels of viable cells were observed with encapsulation in E. americana oligosaccharide extract. No surviving free cells were found in week 4. Yoghurt prepared with encapsulated cells showed less acidification than with free cells. Antibacterial activity of L. plantarum TISTR1465 before pH neutralisation against Clostridium perfringens ATCC13124, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Salmonella Typhimurium ATCC13311 was higher than after pH neutralisation. Encapsulation by extrusion enhanced antibacterial activity of the cells against enteropathogenic bacteria. The antibacterial activity of encapsulated cells against Gram-positive bacteria was higher than that against Gram-negative bacteria. Results indicates that L. plantarum TISTR1465 encapsulated with E. americana oligosaccharide extract showed potential for application as a functional food additive.