Bifidobacterium longum was microencapsulated by extrusion technique and added in fresh milk tofu and pineapple juice. Microencapsulation of B. longum with Eleutherine americana extract, oligosaccharides extract, and commercial fructo-oligosaccharides was assessed for the bacterial survival after sequential exposure to simulated gastric and intestinal juices, and refrigeration storage. Microencapsulated B. longum with the extract and oligosaccharides extract in the food products showed better survival than free cells under adverse conditions. Sensory analysis demonstrated that the products containing co-encapsulated bacterial cells were more acceptable by consumers than free cells. Pineapple juice prepared with co-encapsulated cells had lower values for over acidification, compared with the juice with free cells added. This work suggested that microencapsulated B. longum with E. americana could enhance functional properties of fresh milk tofu and pineapple juice.

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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.

Microencapsulation using extrusion and emulsion techniques was prepared for Bifidobacterium longum protection against sequential exposure to simulated gastric and intestinal juices, refrigeration storage and heat treatment. Eleutherine americana was used as the co-encapsulating agent. Hydrolysis of E. americana by gastric and intestinal juices was also determined. E. americana and its oligosaccharide extract demonstrated their resistance to low pH and partial tolerance to human α-amylase. Microencapsulated B. longum with E. americana and oligosaccharide extract prepared by the extrusion technique survived better than that by the emulsion technique under adverse conditions. Survival of microencapsulated cells after exposure to the juices and refrigeration storage was higher than free cells at Weeks 2 and 4. In addition, the viability of microencapsulated cells was better than free cells at 65 °C for 15 min. This work suggested that microencapsulated B. longum with E. americana offers the effective delivery of probiotics to colon and maintains their survival in food products.

This experiment was carried out to determine the growth stimulation/inhibition effect of popular herbal extracts on intestinal microbiota and pathogenic bacteria. A paper disc agar diffusion method was employed for preliminary data. All extracts failed to promote intestinal microbiota growth around the discs. Green tea (Camellia sinensis) and Eleutherine americana did not produce inhibition zones against all intestinal microbiota, but inhibited Gram-positive pathogenic bacteria. All pure compounds, except eleutherin demonstrated antibacterial activity against all bacteria. Growth response of the substances on intestinal microbiota were further investigated by viable counts. Eleutherin from E. americana did not produce antibacterial antagonism against important groups of intestinal microbiota. In contrast, E. americana extract and eleutherin at minimal inhibitory concentration (MIC) and 4 MIC showed significant inhibition on growth of Grampositive pathogenic bacteria. The results indicated that both E. americana extract and eleutherin exerted dual beneficial effects to the host by regulating beneficial bacteria and inhibiting pathogenic bacteria.