Microbial Diversity and Metabolite Profile of Fermenting Millet in the Production of Hausa koko, a Ghanaian Fermented Cereal Porridge

Abstract

Hausa koko is an indigenous porridge processed from millet in Ghana. The process involves fermentation stages, giving the characteristic organoleptic properties of the product that is produced largely at a small-scale household level and sold as a street food. Like many other indigenous foods, quality control is problematic and depends on the skills of the processor. In order to improve the quality of the product and standardize the process for large-scale production, we need a deeper understanding of the microbial processes. The aim of this study is to investigate the microbial community involved in the production of this traditional millet porridge and the metabolites produced during processing. High-throughput amplicon sequencing was used to identify the bacterial (16S rRNA V4 hypervariable region) and fungal [Intergenic Transcribed Spacer (ITS)] communities associated with the fermentation, while nuclear magnetic resonance (NMR) was used for metabolite profiling. The bacterial community diversity was reduced during the fermentation processes with an increase and predominance of lactobacilli. Other dominant bacteria in the fermentation included Pediococcus, Weissella, Lactococcus, Streptococcus, Leuconostoc, and Acetobacter. The species Limosilactobacillus fermentum and Ligilactobacillus salivarius accounted for some of the diversities within and between fermentation time points and processors. The fungal community was dominated by the genus Saccharomyces. Other genera such as Pichia, Candida, Kluyveromyces, Nakaseomyces, Torulaspora, and Cyberlindnera were also classified. The species Saccharomyces cerevisiae, Stachybotrys sansevieriae, Malassezia restricta, Cyberlindnera fabianii, and Kluyveromyces marxianus accounted for some of the diversities within some fermentation time points. The species S. sansevieria and M. restricta may have been reported for the first time in cereal fermentation. This is the most diverse microbial community reported in Hausa koko. In this study, we could identify and quantify 33 key different metabolites produced by the interactions of the microbial communities with the millet, composed of organic compounds, sugars, amino acids and intermediary compounds, and other key fermentation compounds. An increase in the concentration of organic acids in parallel with the reduction of sugars occurred during the fermentation process while an initial increase of amino acids followed by a decrease in later fermentation steps was observed.

Investigating the effect of natural fermentation in modifying the physico‐functional, structural and thermal characteristics of pearl and finger millet starch

“…16 Antony et al, 35 showed that natural fermentation of FM increased the LAB count significantly during the first 24 h of fermentation. A more recent study by Atter et al, 36 also highlighted that in Hausa koko (a fermented millet-based porridge) LAB count increased during the first 12-24 h fermentation. LAB may contribute to the formation of lactic acid while yeast may produce succinic acid resulting in acidification of the starch slurry.…”

The importance and mitigation of mycotoxins and plant toxins in Southeast Asian fermented foods

“…However, following food fermentation, ffs can still contain significant concentration of mycotoxins, particularly when the raw material or substrate is highly contaminated. Moreover, some fermentation processes provide favorable conditions for the growth and production of mycotoxins by toxigenic fungal species of Aspergillus , Fusarium and Penicillium genera 102 , 103 . In addition, fermentation conditions such as low pH, facilitate the hydrolysis of conjugated mycotoxins (such as deoxynivalenol-3-glucoside and zearalenone-16-glucoside) back to their precursor mycotoxins, which ultimately, result in the accumulation of mycotoxins.…”

Genotypic and Phenotypic Diversity of Kluyveromyces marxianus Isolates Obtained from the Elaboration Process of Two Traditional Mexican Alcoholic Beverages Derived from Agave: Pulque and Henequen (Agave fourcroydes) Mezcal

“…This species has also been isolated from plants such as agave [ 18 ]; fruits such as overripened mango pulp [ 19 ]; vegetables such as rotting onions [ 20 ]; and agro-industrial residues in sugar mills [ 21 ], sugarcane bagasse hydrolysates [ 22 ], blue agave bagasse [ 23 ], coffee wet processing wastewater [ 24 ], and distillery effluents and molasses [ 25 ]. K. marxianus is also part of the microbiota involved in the fermentation of cereal-based African fermented beverages [ 26 ], French cider [ 27 ], Georgian wine [ 28 ], Brazilian cachaça [ 29 ], and Mexican agave-based spirits tequila and mezcal [ 30 , 31 , 32 ].…”