Department of Scienze del Suolo, della Pianta e degli Alimenti, University of Bari Aldo Moro, via Amendola 165/a., Bari, 70126, Italy.
Int J Food Microbiol. 2013 May 15;163(2-3):71-9. doi: 10.1016/j.ijfoodmicro.2013.02.010. Epub 2013 Mar 1.
The lactic acid bacteria and yeast microbiota of eighteen sourdoughs used for the manufacture of some traditional Italian sweet leavened baked goods were studied through culture-dependent method and pyrosequencing. Flours used for back slopping and sourdoughs were also biochemically characterized. Principal component analysis was applied to explore eventual correlations between process parameters applied during back slopping, some flour nutrients, profile of microbiota, and biochemical characteristics of sourdoughs. The median values of the cell density of lactic acid bacteria and yeasts were 8.05 and 7.03 log CFU/g, respectively. As shown by culture-dependent method, Lactobacillus sanfranciscensis was identified in all the sourdoughs, except for Panaredda and Torcolo di San Costanzo. For eleven sourdoughs, all the lactic acid bacteria isolates were allotted to this species. For Buccellato di Lucca, Mbriagotto, Pandoro, and Nadalin sourdoughs, at least 80% of the isolates was allotted to this species. Other lactic acid bacteria isolated with a relatively high frequence were Lactobacillus plantarum and Leuconostoc citreum. Pyrosequencing confirmed and complemented the culture-dependent approach, detecting L. sanfranciscensis also in Panaredda and Torcolo di San Costanzo sourdoughs. Saccharomyces cerevisiae was identified in all the sourdoughs, except for Mbriagotto, Ciambella di Mosto and Pandolce Genovese. These latter sourdoughs harbored strains of Candida humilis, whereas five sourdoughs combined the presence of both yeast species. Positive correlations were found between time of back slopping and cell density and main metabolites of lactic acid bacteria. Percentage of sourdough used as inoculum was mainly correlated with the cell density of yeasts and the concentration of ethanol. This study provided a comprehensive and comparative approach to highlight the dominant microbiota of Italian sourdoughs, which could be exploited further to guarantee a highly reproducible quality of the Italian sweet goods studied, while preserving their traditional trait.
使用培养依赖法和焦磷酸测序法研究了用于制造一些传统意大利甜发酵烘焙食品的 18 种发酵面团中的乳酸菌和酵母微生物群。还对用于回混的面粉和发酵面团进行了生化特性分析。应用主成分分析探索了回混过程参数、一些面粉营养物、微生物群谱和发酵面团生化特性之间的潜在相关性。乳酸菌和酵母的细胞密度中位数分别为 8.05 和 7.03 log CFU/g。通过培养依赖法鉴定，除 Panaredda 和 Torcolo di San Costanzo 外，所有发酵面团中均存在 Lactobacillus sanfranciscensis。对于 11 种发酵面团，所有分离的乳酸菌均归属于该种。对于 Buccellato di Lucca、Mbriagotto、Pandoro 和 Nadalin 发酵面团，至少 80%的分离株归属于该种。其他分离频率较高的乳酸菌包括 Lactobacillus plantarum 和 Leuconostoc citreum。焦磷酸测序法证实并补充了培养依赖法，在 Panaredda 和 Torcolo di San Costanzo 发酵面团中也检测到了 L. sanfranciscensis。除 Mbriagotto、Ciambella di Mosto 和 Pandolce Genovese 外，所有发酵面团中均鉴定出 Saccharomyces cerevisiae。后三种发酵面团含有 Candida humilis 菌株，而五种发酵面团同时存在两种酵母。回混时间与乳酸菌细胞密度和主要代谢物之间存在正相关关系。接种用发酵面团的百分比主要与酵母细胞密度和乙醇浓度相关。本研究提供了一种全面和对比的方法来突出意大利发酵面团中的主要微生物群，这可以进一步利用来保证所研究的意大利甜烘焙食品具有高度可重现的质量，同时保留其传统特性。
