Effect of encapsulation of selected probiotic cell on survival in simulated gastrointestinal tract condition

The health benefits of probiotic bacteria have been led to their increasing use in foods. Encapsulation has been investigated to improve their survival. In this study, the selection, encapsulation and viability of lactic acid bacteria (LAB) with probiotic properties in simulated gastrointestinal tract (GIT) condition were investigated. One hundred and fifty isolates of LAB were obtained from 30 samples of raw cow and goat milk and some fermented foods. Nine isolates could survive under GIT condition and only 3 isolates exhibited an antimicrobial activity against all food-borne pathogenic bacteria. Among them, 2 isolates (CM21 and CM53) exhibited bile salt hydrolase activity on glycocholate and glycodeoxycholate agar plates and were identified as Lactobacillus plantarum. CM53 was selected for encapsulation using 1-3% alginate and 2% Hi-maize resistant starch by emulsion system. Viability and releasing ability of encapsulated CM53 in simulated GIT condition was increased in accordance to the alginate concentration and incubation time, respectively

Screening of lactic acid bacteria from gastrointestinal tracts of marine fish for their potential use as probiotics

One hundred and sixty isolates of lactic acid bacteria (LAB) with inhibitory activity against pathogenic Escherichia coli were isolated from gastrointestinal tracts of fish, shrimp and shellfish. One hundred and sixteen isolates were obtained from fish, twenty isolates from shrimp and twenty-four isolates from shellfish. Three strains were selected based on their bile and acid tolerances. All acid-tolerant strains showed inhibitory activity against human pathogens, including Staphylococcus aureus, Listeria monocytogenes, Salmonella sp. and Escherichia coli. However, the antibacterial activities were lost when the culture supernatants were neutralized to pH 6.5- 7.0 and treated with catalase, indicating that the inhibition may be contributed by acid and hydrogen-peroxide production of the strains. Nucleotide sequences of their 16s rDNA showed 98% (655/668 bp), 97% (691/712 bp) and 98% (492/501 bp) homology to Pediococcus pentosaceus LM2, Pediococcus pentosaceus SL4 and Enterococcus faecium SF, respectively

Antimicrobial activities of essential oils and crude extracts from tropical Citrus spp. against food-related microorganisms

Ethyl acetate extracts and hydrodistillated-essential oils from peels of Citrus spp. were investigated for their antimicrobial activities against food related microorganisms by broth microdilution assay. Overall, ethyl acetate extracts from all citrus peels showed stronger antimicrobial activities than their essential oils obtained from hydrodistillation. The ethyl acetate extract of kaffir lime (Citrus hystrix DC.) peel showed broad spectrum of inhibition against all Gram-positive bacteria, yeast and molds including Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Saccharomyces cerevisiae var. sake and Aspergillus fumigatus TISTR 3180. It exhibited minimum inhibitory concentration (MIC) values of 0.28 and 0.56 mg/ml against Sac. cerevisiae var. sake and B. cereus, respectively while the minimum bactericidal concentration (MBC) values against both microbes were 0.56 mg/ml. The MIC values of the extract against L. monocytogenes, A. fumigatus TISTR 3180 and S. aureus were 1.13 mg/ml while the MBC values against L. monocytogenes as well as A. fumigatus TISTR 3180 and S. aureus were 2.25 and 1.13 mg/ml, respectively. The major components of the ethyl acetate extract from kaffir lime were limonene (31.64 %), citronellal (25.96 %) and b-pinene (6.83 %) whereas b-pinene (30.48 %), sabinene (22.75 %) and citronellal (15.66 %) appeared to be major compounds of the essential oil obtained from hydrodistillation

Applications of Microencapsulated Bifidobacterium Longum with Eleutherine Americana in Fresh Milk Tofu and Pineapple Juice

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

Preparation of Eleutherine americana-Alginate Complex Microcapsules and Application in Bifidobacterium longum

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