The objective of this study was to microencapsulate Saccharomyces boulardii using the emulsion technique. To microencapsulate the yeast, alginate sodium blended with inulin and mucilage from Opuntiaficus-indica was used as a coating material. The textural properties of the gels formed by the encapsulating materials and the in vitro viability of the yeast strain in the simulated conditions were studied. Textural profile analyses of the gels revealed differences (p < 0.05) in hardness because alginate produced stronger gels, whereas the incorporation of other hydrocolloids with alginate decreased gel strength and resulted in a more uniform, cohesive gel matrix. When alginate was blended with mucilage and inulin, encapsulated yeast presented higher counts and more viable cells, as compared to free yeast following 30 days of storage at 4 °C. Encapsulated and free yeast had 76.1% and 63.3%, respectively, of cell viability after 35 days of storage.

Background: Saccharomyces boulardii is a probiotic clinically effective in the prevention and treatment of antibiotic induced diarrhea in both children and adults, Clostridium difficile infections, inflammatory bowel disease, and other gastrointestinal disorders. However, the microorganisms need to survive the gastrointestinal transit and arrive to their action site alive in order to exert their beneficial effects. Microencapsulation is an alternative to improve the viability of probiotic in foods which can also survive in the gastrointestinal conditions. Freeze--drying is a method of dehydration that does not affect nutrients and bioactive compounds, such as probiotics contained in foods. All of them will increase the survival rate of S. boulardii.Purpose of this study: This study focused on formulae freeze-dried yogurt containing inulin, vegetable palm oil, and S. boulardii, both as free cells and in microencapsulated form. Also, theeffect of ampicillin associated S. boulardii.Methods: Yogurts were given to an “in vivo” digestion process, using male Wistar rats. The survival of S. boulardii was subsequently evaluated in colon and feces. For this study, six treatments of four of rats were used: i) control rats ii) rats fed with yogurt containing S. boulardii as free cells, iii) rats fed with yogurt containing S. boulardii in micro-encapsulated form, iv) control rats fed with penicillin, v) rats fed with ampicillin plus yogurt containing S. boulardii as free cells, and vi) rats fed with penicillin plus yogurt containing S. boulardii in micro-encapsulated form.Results: The study demonstrated it was feasible to freeze-dry the S. boulardii and incorporate it into a yogurt made with skim milk, inulin, and unsaturated vegetable oil. The freeze-drying process not affected the survival of the S. boulardii (p<0.05). Microencapsulation increased the survival of S. boulardii on 1.77-Log CFU/g, and the presence of S. boulardii was only detected in colon and feces of those rats which ingested ampicillin, regardless to the formula contained the probiotic.Conclusion: This study demonstrated that freeze-drying maintains the survival of S. boulardii in the evaluated foods and that micro-encapsulation increases the survival of this probiotic. Furthermore, S. boulardii was installed in the gastrointestinal tract when the microbial flora was  damaged by ampicillin.Keywords: Yogurt, probiotic, Saccharomyces boulardii, micro-encapsulation, freeze-drying.

The aim of this work was to develop and characterize a functional food (fresh cheese) by incorporation of a probiotic microorganism (Sacharomyces boulardii) and a prebiotic agent (inulin), both encapsulated with sodium alginate and cactus mucilage. The microorganism viability incorporated in the fresh cheese in free and encapsulated form was evaluated at the beginning and the end of the cheese shelf life. The organoleptic characteristics (color, odor, taste, texture and overall acceptability) of the elaborated cheese were evaluated too. The viability of the probiotic microorganism added in encapsulated form was greater than that shown by the microorganism added unencapsulated, after 30 days of keeping the cheeses at 4°C. The addition of the symbiotic S. boulardii e inulin did not alter the chemical composition of the cheese, but improves its organoleptic properties and makes it more acceptable to consumers. The viability of microorganisms during all cheese shelf life satisfies the minimum quantity recommended by the Food and Agriculture Organization for this cheese is considered as probiotic food.

Introducción: Un alimento funcional contiene en su formulación una o más sustancias que generan bienestar a la salud humana como son probióticos, prebióticos y ácidos grasos, entre otros. En los alimentos funcionales los microorganismos probióticos deben permanecer viables y activos en el alimento y durante el pasaje gastrointestinal, para garantizar su potencial efecto benéfico en el huésped. En el presente estudio se evaluó la viabilidad de la levadura probiótica Saccharomyces boulardii tanto de forma libre como encapsulada bajo condiciones de acidez, adaptada a un queso fresco.Método: La levadura fue expuesta en el alimento tanto en forma  libre como encapsulada. Los materiales usados para encapsular fueron una mezcla de alginato de sodio, inulina y mucílago de nopal (Opuntia ficus-indica). Para la liberación del microorganismo, el estudio se realizó a pH  de 2.0 y 6.5, simulándose las condiciones de acidez de estómago y colon respectivamente, a diferentes tiempos de exposición de 0, 60, 120 y 180 min.Resultados: A pH de 2.0 se observó mayor pérdida en la viabilidad del probiótico en forma libre, la cual fue de 23.72, 27.03 y 33.02 % respectivamente, con respecto a la viabilidad inicial; cuando el microorganismo se adicionó al queso en forma encapsulada, su pérdida de viabilidad a los mismos tiempos de exposición fue de 5.74, 14.24 y 18.81%, manteniendo mayor supervivencia. Por otra parte, a pH de 6.5 el probiótico libre en el alimento mostró una pérdida de viabilidad de 2.23, 3.50 y 5.94%, en cambio de forma encapsulada la pérdida de viabilidad fue de 0.95, 2.20 y 3.03%, respectivamente, observándose mayor supervivencia que en estado libre.                      Conclusión: El queso fresco mantuvo viable el nivel de supervivencia de Saccharomyces boulardii, particularmente cuando fue adicionado en forma encapsulada comparado a cuando fue incorporado en estado libre.

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