Survival rate of Saccharomyces boulardii adapted to a functional freeze-dried yoghurt, related to processing, storage and digestion by experimental Wistar rats

Abstract

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.