Microbial diversity and metabolite profile of fermenting millet in the production of Hausa koko, a Ghanaian fermented cereal porridge

Diaz M, Atter A, Tano-Debrah K, Parry-Hanson Kunadu A, Mayer MJ, Colquhoun IJ, Nielson D, Baker D, Narbad A, Amoa-Awua . (2021)

Frontiers in Microbiology, 12, 681983


Hausa koko is an indigenous porridge processed from millet in Ghana. The process involves fermentation stages, giving the characteristic organoleptic properties of the product which is produced largely at 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. One potential way of improving the quality of the product and standardizing the process for large-scale production, is deepening the understanding of the microbial process. High throughput amplicon sequencing was used for identifying the bacterial (16S rRNA V4 hypervariable region) and fungal (Intergenic Transcribed Spacer (ITS)) communities associated with the fermentation, whilst 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 the genus Lactobacillus. Other dominant bacteria in the fermentation included Pediococcus, Weissella, Lactococcus, Streptococcus, Leuconostoc and Acetobacter. The species Lactobacillus fermentum and Lactobacillus 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, 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 Stachybotrys sansevieriae and Malassezia 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 thirty three key different metabolites produced by the interactions of the microbial communities with the millet, comprised of organic compounds, sugars, amino acids and intermediary compounds and other key fermentation compounds. An increase in the concentration of organic acids in parallel to 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


Frontiers in Microbiology, 12, 681983


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