Coated alginate–chitosan particles to improve the stability of probiotic yeast

Summary External ionic gelation is a technique with a great potential for the protection of probiotics for use in food and pharmaceutic products. In this study, particles containing Saccharomyces boulardii produced using sodium alginate and a chitosan coating were evaluated. The physical–chemical parameters (moisture/water activity/hygroscopicity) of the dried particles, stability during 120 days of storage and yeast resistance to simulated gastrointestinal conditions were analysed. During storage (30 °C), greater yeast protection in the alginate–chitosan particles was observed, with a reduction of 1.05 log. Although the free cells presented low resistance, the encapsulated yeast was resistant to the simulated gastrointestinal conditions. At the end of the gastrointestinal simulation, the concentration ranged around 9.15–8.01 and 9.25–8.82 logCFU g −1 in alginate and alginate–chitosan particles, respectively. The S. boulardii particles showed greater resistance to environmental factors, allowing the delivery of an ingredient that could be used to add value to food products.