Ruiz Rodríguez L, Vera Pingitore E, Rollan G, Martos G, Saavedra L, Fontana C, Hebert E M, Vignolo G
Centro de Referencia para Lactobacilos (CERELA), CONICET, Tucumán, Argentina.
Istituto di Microbiologia-Centro Ricerche Biotecnologiche, Università Cattolica del Sacro Cuore, Piacenza-Cremona, Italy.
Lett Appl Microbiol. 2016 Aug;63(2):147-54. doi: 10.1111/lam.12604.
Spontaneous fermented sourdoughs prepared from amaranth flour were investigated for the presence of autochthonous lactic acid bacteria (LAB) predominating microbiota. The doughs were fermented with daily backslopping on a laboratory scale at 30°C for 10 days. LAB counts ranged from 2·60 to 8·54 log CFU g(-1) with a pH declined from 6·2 to 3·8 throughout fermentation. The combined use of randomly amplified polymorphic DNA (RAPD)-PCR analysis and sequence analysis of 16S rRNA was applied for LAB intraspecies differentiation and taxonomic identification, respectively. Enterococcus, Pediococcus and Lactobacillus species were present in amaranth sourdoughs (AS). After the first refreshment step, Lactobacillus plantarum dominated AS until the end of fermentation. In coincidence, when DGGE analysis was performed, the occurrence of a progressive change in bacterial communities allowed the selection of Lact. plantarum as a dominant species. Moreover, technological, functional and safety characteristics of representative RAPD-biotypes were investigated. Lact. plantarum CRL1898 was selected as a potential candidate for gluten-free amaranth sourdough starter.
Nowadays, there is an increasing interest in ancient noncereal gluten-free (GF) crops such as amaranth, due to their reported nutritional and health benefits. However, the use of these grains is still limited to traditional foods and bread making processes that are not yet well standardized. Results on the dynamics of autochthonous lactic acid bacteria (LAB) microbiota during laboratory spontaneous amaranth sourdoughs (AS) fermentation will contribute to overcome challenges for GF-fermented products development. In addition, knowledge about LAB diversity involving Enterococcus, Pediococcus and Lactobacillus species, with Lactobacillus plantarum predominating during AS fermentation, and their technological and functional properties provides the basis for the selection of autochthonous strains as starters cultures for novel gluten-free bakery products with enhanced nutritional, sensory and/or safety quality.
对用苋菜籽粉制备的自发发酵酸面团进行了研究，以确定其中占主导地位的微生物群——本地乳酸菌（LAB）的存在情况。面团在实验室规模下于30°C进行每日回接发酵，持续10天。LAB计数范围为2.60至8.54 log CFU g⁻¹，在整个发酵过程中pH值从6.2降至3.8。分别将随机扩增多态性DNA（RAPD）-PCR分析和16S rRNA序列分析结合使用，用于LAB种内分化和分类鉴定。苋菜籽酸面团（AS）中存在肠球菌、片球菌和乳杆菌属物种。在第一次回接步骤之后，植物乳杆菌在AS中占主导地位直至发酵结束。巧合的是，当进行变性梯度凝胶电泳（DGGE）分析时，细菌群落的逐渐变化使得能够选择植物乳杆菌作为优势菌种。此外，还研究了代表性RAPD生物型的工艺、功能和安全特性。植物乳杆菌CRL1898被选为无麸质苋菜籽酸面团发酵剂的潜在候选菌株。
如今，由于其已报道的营养和健康益处，人们对诸如苋菜籽等古老的非谷物无麸质（GF）作物的兴趣日益增加。然而，这些谷物的使用仍仅限于尚未得到很好标准化的传统食品和面包制作工艺。关于实验室自发苋菜籽酸面团（AS）发酵过程中本地乳酸菌（LAB）微生物群动态的研究结果将有助于克服GF发酵产品开发面临的挑战。此外，关于LAB多样性的知识，包括肠球菌、片球菌和乳杆菌属物种，以及在AS发酵过程中占主导地位的植物乳杆菌及其工艺和功能特性，为选择本地菌株作为新型无麸质烘焙产品的发酵剂培养物提供了基础，这些产品具有更高的营养、感官和/或安全质量。
