Department of Microbiology, Babcock University, Ilishan Remo, Ogun State, Nigeria.
Pathogenic Yeast Research Group, Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, South Africa.
Food Res Int. 2021 May;143:110241. doi: 10.1016/j.foodres.2021.110241. Epub 2021 Feb 25.
Ogi is a fermented cereal beverage, made primarily from maize (Zea mays) and rarely from millets. Unlike maize-based ogi, little is known about the bacterial community and mycotoxin profile during the production of millet-based ogi. Therefore, the bacterial community dynamics and mycotoxin reduction during ogi processing from three millet varieties were investigated using next-generation sequencing of the 16S rRNA gene and liquid chromatography-tandem mass spectrometry, respectively. A total of 1163 amplicon sequence variants (ASVs) were obtained, with ASV diversity across time intervals influenced by processing stage and millet variety. ASV distribution among samples suggested that the souring stage was more influenced by millet variety than the steeping stage, and that souring may be crucial for the quality attributes of the ogi. Furthermore, bacterial community structure during steeping and souring was significantly differentiated (PERMANOVA, P < 0.05) between varieties, with close associations observed for closely-related millet varieties. Taxonomically, Firmicutes, followed by Actinobacteria, Bacteroidetes, Cyanobacteria and Proteobacteria phyla were relatively abundant (>1%). Lactic acid bacteria, such as Burkholderia-Caballeronia-Paraburkholderia, Lactobacillus, Lactococcus and Pediococcus, dominated most fermentation stages, suggesting their roles as key fermentative and functional bacteria in relation to mycotoxin reduction. About 52-100%, 58-100% and 100% reductions in mycotoxin (aflatoxins, beauvericin, citrinin, moniliformin, sterigmatocystin and zearalenone) concentrations were recorded after processing of white fonio, brown fonio and finger millet, respectively, into ogi. This study provides new knowledge of the dominant bacterial genera vital for the improvement of millet-based ogi through starter culture development and as well, elucidates the role of processing in reducing mycotoxins in millet ogi.
奥吉是一种发酵的谷物饮料，主要由玉米（Zea mays）制成，很少用小米制成。与基于玉米的奥吉不同，关于基于小米的奥吉生产过程中的细菌群落和霉菌毒素谱知之甚少。因此，分别使用 16S rRNA 基因的下一代测序和液相色谱-串联质谱法研究了三种小米品种奥吉加工过程中的细菌群落动态和霉菌毒素减少情况。共获得 1163 个扩增子序列变异体（ASV），时间间隔内的 ASV 多样性受加工阶段和小米品种的影响。样品中 ASV 的分布表明，酸化阶段受小米品种的影响大于浸泡阶段，酸化可能对奥吉的质量属性至关重要。此外，浸泡和酸化过程中的细菌群落结构在品种间有显著差异（PERMANOVA，P<0.05），密切相关的小米品种之间存在密切关联。分类学上，厚壁菌门、放线菌门、拟杆菌门、蓝细菌门和变形菌门相对丰度较高（>1%）。乳杆菌属、乳球菌属和肠球菌属等乳酸菌在大多数发酵阶段占主导地位，这表明它们在与霉菌毒素减少有关的关键发酵和功能细菌中发挥作用。在将白高粱、棕高粱和珍珠小米加工成奥吉后，霉菌毒素（黄曲霉毒素、伏马菌素、桔霉素、单端孢霉烯族化合物、玉米赤霉烯酮和玉米赤霉烯酮）的浓度分别降低了 52-100%、58-100%和 100%。本研究为通过开发起始培养物来改善基于小米的奥吉的重要优势细菌属提供了新知识，同时阐明了加工在降低小米奥吉中霉菌毒素方面的作用。
