Farklı Bölge Buğday Unlarından Üretilen Ekşi Hamurlardan İzole Edilen Endojen Mayaların Bazı Teknolojik ve İmmünojenik Özelliklerinin Belirlenmesi

Abstract

In this study, yeast colonies were isolated from sourdoughs that were prepared with wheat flours which were collected from Turkey’s different areas meanwhile one of them was readymade sourdough. The isolates that were identified by MALDI-TOF Mass Spectrometry were analysed for their growth at 37°C and in high sugar concentration. 10 of 12 isolates were Saccharomyces cerevisiae according to the pre-idenficiation which was done by MALDI-TOF MS. Only E1 (coded isolate) could grow in high sugar concentration. Bi1, Bi5, Bi7 couldn’t grow in GPY agar at 37°C. Only Bi1 couldn’t grow in GPY broth at 37°C. The properties which can be important for bread making (optical density dependant growth rate, glucose-sugar fermentation, growth in several salt concentrations, growth at low pH values, killer activity, sensivity, proteolytic activity) of the yeast isolates were investigated and the convenient isolates‘ sequence analysis was performed. All of the yeast isolates could ferment glucose. Ch1 could ferment saccharose within 24 hours. Bi1, Bi5, Bi7 could ferment fructose within 24 hours. Bi5 fermented glucose in glucose fermentation medium within 24 hours. PeC, Bi1, Bi5 fermented glucose in sugar fermentation medium within 24 hours. All of the isolates were grown at pH 2.5-3.5-4.5-6.57 values and at 2-3-4-5 % (w/v) salt concentrations. Neither of the isolates showed killer and proteolytic activity. All of the isolates were found sensitive to K1 and K2 killer toxins except PeC and PeA1. While M2 reached the highest number at the end of 24 hours among the Saccharomyces cerevisiae isolates, Bi5 reached the highest number at the end of 24 hours among the Saccharomyces uvarum/ Saccharomyces bayanus isolates in the optical density dependant growth rate experiment. 6 of the isolates (C1, Ch1, E1, M2, PeF, PeA2) verified as Saccharomyces cerevisiae with sequence analysis. Caco-2 (Human colon adenocarcinoma cell line) and THP-1 (Human monocytic cell line) cells were used to investigate cytotoxicity of the some isolates with MTT Assay. BY1-1, E1, M2, PeA2, PeF and Ch1 caused growth of THP-1 and Caco-2 cells according to MTT Assay. THP-1 cells were differentiated to macrophages by applying PMA and were interacted with the inactive yeast isolates to determine effect of the yeast isolates to immune regulation. TNF-α, IL-4, IL-5 and IL-10 secretion from the cells was measured from the cell culture supernatants with ELISA method. t- Test and two way ANOVA were implemented by comparing the isolates’ cytokine levels with the negative control. Differences between the isolates were evaluated by using one way ANOVA. PeF, C1, BY1-1 and M2 caused significant amounts of TNF-α release from macrophages (p<0.05). The difference between the isolates was found significant in terms of TNF-α release level (p<0.05). IL-4 levels of Bi5 and Ch1 were lower than the negative control value and they decreased IL-4 release from macrophages. The difference between the isolates was not determined significant in terms of IL-4 release (p>0.05). The highest IL-5 release was in C1 and its difference from the negative control was found significant (p<0.05). IL-5 levels of Bi5, Bi7, Ch1, PeA2 and PeA1 were lower than the negative control value and the difference between them was found significant (p<0.05). The difference between the isolates in terms of IL-5 release level was found significant (p<0.05). M2, Bi7, C1, PeF, BY1-1, PeC and PeA1 increased IL-10 release from macrophages and the difference between the isolates was found significant in this respect (p<0.05). PeF and M2 have a potential to be used as yeast starter for bread making in terms of their technological properties accordingly. More extensive studies should be performed about whether they are endemic strains indigenous to Turkey or not and to commercialize them. The subject was lighted up for the studies that will be able to done about possible effects of yeasts to human health by presenting the effects of the yeast isolates to THP-1 and Caco-2 cancer cell lines as well as presenting levels of TNF-α, IL-4, IL-5 and IL-10 cytokines which come out with the interaction between the yeasts and macrophages.