Determination of probiotic and technological properties of some endogenous yeast isolated from various food and investigation of the effect of microencapsulation on theese properties

Saccharomyces, Candida, Kluyveromyces, Pichia and Torulopsis are the most abundant species of fermented foods. Today, there is an increasing interest in assessing probiotics as well as technological properties of yeast. In this study, 165 yeasts were isolated from fermented products obtained from Bolu, Samsun, Ankara, Erzurum, İzmir, Bursa and Aydın provinces. Some probiotic properties of isolated yeasts have been determined. After identifying yeast isolates using VITEK II biochemical, FT-IR spectroscopic, MALDI-TOF MS Biotyper identification system, 35 potential isolates with superior technological and probiotic properties were selected. Selected yeasts strains were identified exactly by using 26S rRNA sequence analysis method. According to the results of the molecular identification, it was found that Saccharomyces cerevisiae was the predominant strain among the isolates and this was followed by Pichia spp., Galactomyces spp. Kluyveromyces marxianus and Yarrowia lipolytica strains respectively. The properties of resistance to 0,3% and 1% of bile salt and the growth characteristics at high temperature (37°C and 42°C), artificial gastrointestinal environment and low pH were determined for 35 identified strains. According to their best technological and probiotic properties 2 yeast strains (Saccharomyces cerevisiae Y10 ve Yarrowia lipolytica E1) were selected than they were microencapsulated in 1% alginate solution by electrostatic vibration method in microencapsulation process. Some probiotic properties (tolerance to gastric and intestinal environment, low pH and tolerance to bile salt) of the microencapsulated yeasts were determined. Microencapsulated Saccharomyces cerevisiae Y10 and Yarrowia lipolytica E1 maintained their viability at 71,74% and 83,53% in gastric tolerance, 95,86 and 98,68% in intestinal tolerance, 94,77 and 99,06% in bile salt tolerance, 94,92 and 99,07% in low pH tolerance, 94,13% and 99,32% after one month storage at refrigerator temperature, respectively. KEYWORDS: Endogenous Yeast, Probiotic, Microencapsulation