Centro de Referencia para Lactobacilos (CERELA-CONICET), S. M. de Tucumán, Tucumán, Argentina.
Dipartimento di Scienze e Tecnologie Alimentari per una filiera agro-alimentare Sostenibile (DISTAS), Università Cattolica del Sarco Cuore, Cremona-Piacenza, Italy.
Int J Food Microbiol. 2020 Mar 2;316:108425. doi: 10.1016/j.ijfoodmicro.2019.108425. Epub 2019 Nov 6.
Chia, is a gluten-free, rich in proteins, oilseed that is "on trend" as an alternative ingredient in food production, adding nutritional value. As a reservoir of natural biodiversity, lactic acid bacteria development, during spontaneous chia flour fermentation (sourdough) for 10 days, were investigated by culturing and high throughput sequencing (HTS). Culture-dependent analysis showed a rapid increase in total LAB numbers from the second day of sourdough refreshment. Taxonomical identification of LAB isolates by rep-PCR and further 16S rRNA sequencing was performed. Besides Among identified LAB by culture-dependent approach, species from genus Enterococcus were the most abundant; Lactococcus (Lc. lactis), Lactobacillus (L. rhamnosus) and Weissella (W. cibaria) species were also isolated. By HTS, twelve OTUs belonging to LAB genera were identified during chia sourdough fermentation with an increased Lactobacillus diversity. Enterococcus (E.) faecium, E. mundtii, W. cibaria and L. rhamnosus were detected as dominant species in the final propagation stages while Bacillus and Clostridium were mostly present during first fermentation stages. The investigation of biotechnological and safety traits (acidification ability, protein hydrolysis, exopolysaccharides production, antimicrobial activity and antibiotic resistance) of 15 representative LAB strains was performed. Strains characterization led to the selection of Lc. lactis CH179, L. rhamnosus CH34 and W. cibaria CH28 as candidates to be used as novel functional starter culture for gluten-free chia fermented products. As far as we know, this is the first study providing information on the molecular inventory of LAB population during spontaneous fermentation of chia sourdough.
奇亚籽是一种无麸质、富含蛋白质的油籽，作为食品生产中的替代成分，具有增加营养价值的趋势。作为天然生物多样性的储存库，研究了在自发奇亚籽粉发酵（酸面团）过程中，10 天内乳酸菌的发展情况，通过培养和高通量测序（HTS）进行了研究。培养依赖性分析表明，酸面团更新后的第二天，总 LAB 数量迅速增加。通过 rep-PCR 和进一步的 16S rRNA 测序对 LAB 分离株进行了分类鉴定。除了通过培养依赖性方法鉴定的 LAB 外，肠球菌属的物种最为丰富；还分离出乳球菌属（Lc. lactis）、乳杆菌属（L. rhamnosus）和魏斯氏菌属（W. cibaria）的物种。通过 HTS，在奇亚籽酸面团发酵过程中鉴定出 12 个属于 LAB 属的 OTU，其中乳杆菌属的多样性增加。在最终繁殖阶段，检测到肠球菌属（E. faecium、E. mundtii、W. cibaria 和 L. rhamnosus）为优势种，而芽孢杆菌属和梭菌属主要存在于第一发酵阶段。对 15 株代表性 LAB 菌株的生物技术和安全性特性（酸化能力、蛋白质水解、胞外多糖生产、抗菌活性和抗生素耐药性）进行了研究。菌株特征分析导致选择 Lc. lactis CH179、L. rhamnosus CH34 和 W. cibaria CH28 作为新型功能性发酵剂，用于无麸质奇亚发酵产品。据我们所知，这是首次在自发奇亚酸面团发酵过程中提供关于 LAB 群体分子清单的研究。
