Syrokou Maria K, Themeli Christina, Paramithiotis Spiros, Mataragas Marios, Bosnea Loulouda, Argyri Anthoula A, Chorianopoulos Nikos G, Skandamis Panagiotis N, Drosinos Eleftherios H
Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos St., 11855 Athens, Greece.
Department of Dairy Research, Institute of Technology of Agricultural Products, Hellenic Agricultural Organization "DEMETER", 3 Ethnikis Antistaseos St., 45221 Ioannina, Greece.
Foods. 2020 Nov 4;9(11):1603. doi: 10.3390/foods9111603.
The aim of the present study was to assess the microecosystem of 13 homemade spontaneously fermented wheat sourdoughs from different regions of Greece, through the combined use of culture-dependent (classical approach; clustering by Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) and identification by PCR species-specific for , and sequencing of the 16S-rRNA and 26S-rRNA gene, for Lactic Acid Bacteria (LAB) and yeasts, respectively) and independent approaches [DNA- and RNA-based PCR-Denaturing Gradient Gel Electrophoresis (DGGE)]. The pH and Total Titratable Acidity (TTA) values ranged from 3.64-5.05 and from 0.50-1.59% lactic acid, respectively. Yeast and lactic acid bacteria populations ranged within 4.60-6.32 and 6.28-9.20 log CFU/g, respectively. The yeast: LAB ratio varied from 1:23-1:10,000. A total of 207 bacterial and 195 yeast isolates were obtained and a culture-dependent assessment of their taxonomic affiliation revealed dominance of in three sourdoughs, in four sourdoughs and co-dominance of these species in two sourdoughs. In addition, dominated in two sourdoughs and and in one sourdough each. , , , . and were also recovered from some samples. Regarding the yeast microbiota, it was dominated by in 11 sourdoughs and and in one sourdough each. and were also recovered from one sample. RNA-based PCR-DGGE provided with nearly identical results with DNA-based one; in only one sample the latter provided an additional band. In general, the limitations of this approach, namely co-migration of amplicons from different species to the same electrophoretic position and multiband profile of specific isolates, greatly reduced resolution capacity, which resulted in only partial verification of the microbial ecology detected by culture-dependent approach in the majority of sourdough samples. Our knowledge regarding the microecosystem of spontaneously fermented Greek wheat-based sourdoughs was expanded, through the study of sourdoughs originating from regions of Greece that were not previously assessed.
本研究的目的是通过联合使用依赖培养的方法（经典方法；通过随机扩增多态性DNA-聚合酶链反应（RAPD-PCR）进行聚类，并分别通过针对乳酸菌（LAB）和酵母的16S-rRNA和26S-rRNA基因的种特异性PCR进行鉴定和测序）和非依赖培养的方法[基于DNA和RNA的PCR-变性梯度凝胶电泳（DGGE）]，评估来自希腊不同地区的13种自制自发发酵小麦酸面团的微生态系统。pH值和总可滴定酸度（TTA）值分别在3.64 - 5.05和0.50 - 1.59%乳酸范围内。酵母和乳酸菌数量分别在4.60 - 6.32和6.28 - 9.20 log CFU/g范围内。酵母与LAB的比例在1:23至1:10,000之间变化。共获得207株细菌分离株和195株酵母分离株，对其分类归属的依赖培养评估显示，在三种酸面团中占优势，在四种酸面团中占优势，在两种酸面团中这两个物种共占优势。此外，在两种酸面团中占优势，在一种酸面团中占优势，在一种酸面团中占优势。 、 、 、 。 和 也从一些样品中分离出来。关于酵母微生物群，在11种酸面团中占优势，在一种酸面团中占优势，在一种酸面团中占优势。 和 也从一个样品中分离出来。基于RNA的PCR-DGGE与基于DNA的结果几乎相同；仅在一个样品中，后者出现了一条额外的条带。一般来说，这种方法的局限性，即不同物种的扩增子共迁移到相同的电泳位置以及特定分离株的多带图谱，大大降低了分辨率，这导致在大多数酸面团样品中，仅部分验证了依赖培养方法检测到的微生物生态学。通过对来自希腊以前未评估地区的酸面团进行研究，我们关于自发发酵希腊小麦基酸面团微生态系统的知识得到了扩展。
