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.
