Determination of chemical and microbiological properties of kefir made with Saccharomyces cerevisiae spp. boulardii

Saccharomyces boulardii is a food-borned yeast with proven probiotic properties that successfully treat bacterial, viral and antibiotic-associated acute and chronic diarrhea, and regulates the human gastrointestinal system and allows beneficial microorganisms in the intestines to colonize again. In this study, eight different kefirs were produced by inoculating two different traditional kefir grains (Ankara-G1 and İzmir-G2) and two different industrial kefir starter cultures (Büyüdanem-E1 and Doğadan Bizim-E2) and Saccharomyces boulardii CNCM I-745 (Reflor) probiotic yeast (GSb1, GSb2, ESb1, ESb2) into UHT cow milk. Produced kefirs were stored at 4±1 oC for 21 days. Some chemical (total dry matter, fat and ash content, titratable acidity and pH value), microbiological (TMAB, Lactobacillus spp., mesophilic lactic cocci and yeast count) and sensory properties (consistency, taste and aroma, overall acceptability) of kefir samples were examined on the 1st, 7th, 14th and 21st days of storage. After storage, Lactobacillus spp. (8.0 log cfu/g), the mesophilic lactic cocci (8.0 log cfu/g) and yeast count (6.4 log cfu/g) indicated that S. boulardii adapts well to kefir samples. In addition, it has been determined that the use of S. boulardii in kefir production has no negative effect on the chemical properties of kefir. The effect of the using of S. boulardii for kefir whether containing yeast (G1, G2 and E1) or not (E2) on their chemical, microbiological and sensory properties was determined for the first time. Lactobacillus spp. and S. boulardii interaction in the traditional kefir has been more successful. Ankara-GSb1 kefir containing S. boulardii was the most preferred among kefirs, followed by Ankara-G1 and İzmir-GSb2 kefir samples (p<0.001). The taste of kefir containing S. boulardii has been observed to be softer and more delicious than other kefirs. The probiotic food developed in this research has the potential to be used in clinical applications. Therefore, clinical studies are required.