Predominant yeasts in the sourdoughs collected from some parts of Turkey

Abstract

In the present study, a total of eight sourdough samples were collected from three different bakeries at two different times in Turkey. Also, laboratory-scale sourdough production was conducted by daily back-slopping for 7 days. Microbiological and chemical properties of the sourdoughs were investigated. Yeast species in the sourdoughs were identified by subjecting all presumptive yeast cultures to internal transcribed spacer region amplification of the 5.8S rRNA gene, restriction fragment length polymorphism analysis using Hae III, Hha I, and Hinf I endonucleases, and sequence analysis of the D1/D2 domain of the 26S rDNA gene. A total of seven profiles were determined according to the restriction fragments. Totally, 148 yeast isolates were identified at the species level (≥400 BP, 99% identity) as Saccharomyces cerevisiae (106), Kazachstania bulderi (11), Pichia fermentans (nine), Pichia membranifaciens (eight), Kazachstania servazzii (seven), Kazachstania unispora (four), and Hanseniaspora valbyensis (three). Although collected sourdoughs were produced without using baker's yeast, S. cerevisiae was the most frequently isolated yeast species. This can be related to the contamination of the bakery environment with commercial baker's yeast during the production of other bakery products. The pH and acidity levels of the collected sourdough samples ranged from 3.71 to 3.96 and 6.78 to 23.93 mL 0.1 N NaOH/10 g dough, respectively. Mean values of the content of maltose + sucrose, glucose, fructose, lactic acid, and acetic acid were 2.43, 1.57, 2.67, 7.30, and 1.40 g/kg, respectively. Due to the artisan and regiondependent handling of the sourdough, different biochemical patterns were observed among the collected samples.

Microbial Communities, Metabolites, Fermentation Quality and Aerobic Stability of Whole-Plant Corn Silage Collected from Family Farms in Desert Steppe of North China

“…Kazachstania bulderi was the predominant fungus in S3 and S4 in the present study. This strain was formerly named Saccharomyces bulderi [32] and was first isolated from maize silage as a novel species [33]. The present study first detected C. xylopsoci, R. microspores, and Rhizomucor pusillus in the silage in the form of fungal pathogens.…”

Yeast biodiversity in chickpea sourdoughs and comparison of the microbiological and chemical characteristics of the spontaneous chickpea fermentations

“…Then the cells were harvested and genomic DNA was extracted by InstaGene Matrix kit (Bio‐Rad, Hercules, CA, USA) according to the manufacturer's instructions. For each isolate, a freshly prepared lyticase (L4025, ≥200 units/mg solid, Sigma‐Aldrich, MO, USA) solution (4 U/μl) was added and incubated at 37°C for 1 hr for digestion of the yeast cells (Boyaci‐Gunduz & Erten, 2020). The DNA extracts were stored at −20°C and used for further PCR assays.…”

“…UV/Vis detector (SPD-20A) monitored at 210 nm was used for organic acids analysis. Aminex HPX-87H column (300 x 7.8 mm, Bio-Rad, Hercules, CA, USA) was used for chromatographic separation under the conditions reported previously (Boyaci Gunduz et al, 2020). Analyses were performed in duplicate and the results were given as means ± standard deviation.…”

“…Aliquots of decimal dilutions of CLS and CD samples were prepared by homogenizing 10 g of sample with 90 ml of sterile 0.85% (wt/vol) NaCl (Merck) solution for plate count analyses (Boyaci Gunduz et al, 2020).…”

“…In order to protect such traditional foods, scientific research is very essential. Studies investigating microbiota in chickpea fermentations (Aydin & Çebi, 2019;Boyaci Gunduz et al, 2020;Cebi, 2009;Erginkaya et al, 2016;Hancioglu-Sikili, 2003;Hatzikamari, Kyriakidis, et al, 2007;Hatzikamari, Yiangou, et al, 2007;Katsaboxakis & Mallidis, 1996;Sáez et al, 2018) reported about lactic acid bacteria (LAB), yeasts, Bacillus and Clostridium spp. at genus or species level.…”