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Enhanced viability of probiotic Saccharomyces boulardii encapsulated by layer-by-layer approach in pH responsive chitosan–dextran sulfate polyelectrolytes

Thomas, Midhun Ben, Vaidyanathan, Mahalakshmi, Radhakrishnan, Krishna, Raichur, Ashok M.
Journal of food engineering 2014 v.136 pp. 1-8
Saccharomyces cerevisiae var. cerevisiae, cell viability, chitosan, coatings, dextran, electrolytes, encapsulation, freeze drying, gastrointestinal system, gastrointestinal transit, juices, pH, permeability, probiotics, protective effect, sulfates, yeasts
Saccharomyces boulardii was encapsulated by layer-by-layer technique (LbL) using oppositely charged polyelectrolytes, chitosan and dextran sulfate to protect from degradation during its gastrointestinal transit. The protective effect of the coating was evaluated by checking viability after subjecting the coated cells to lyophilisation and simulated gastrointestinal conditions. During lyophilization, coated S. boulardii was found to have an enhanced viability of 7.74±2.00 log CFU/100mg (5.62×106±2.12CFU/100mg) and 5.53±1.85 log CFU/100mg (3.46×105±1.73CFU/100mg) for uncoated cells. On sequential treatment with simulated gastric and intestinal juice, the coated cells had a viability of 4.59±1.52 log CFU/100mg (3.8×104±1.52CFU/100mg) while only 1.90±0.80 log CFU/100mg (0.79×102±0.81CFU/100mg) of uncoated cells survived. Confocal studies displayed the selective permeability of the coated cells which plays a significant role in maintaining the integrity and viability of the yeast cells. This clearly indicates that LbL is an efficient protective encapsulation technique and it could be potentially used for improving therapeutic applications of yeast.