Microbial Studies and Biochemical Characteristics of Controlled Fermented Afiyo- a Nigerian Fermented Food Condiment from Prosopis africana (Guill and Perr.) Taub
Abstract:
One hundred and fifteen bacterial strains isolated from
fermenting Prosopis africana during a controlled production of
okpehe, a Nigerian food-seasoning condiment most popular among the
middle belt states of Nigeria were characterized as Bacillus subtilis,
Bacillus pumilus, Bacillus licheniformis, Bacillus megaterium,
non-sporing Staphylococcus species and Escherichia coli
according to their differences in morphological, microscopic and
biochemical characteristics using the bacterial taxonomic tools. There was
no isolation of fungi throughout the fermentation period. The biochemical
changes and enzymatic activities in fermenting okpehe mash were
investigated. Reducing sugars increased from 2.0 mg g-1 to 11.6
mg g-1 during the first 2 days of fermentation but subsequently
decreased to 7.8 mg g-1 at day 6 while total soluble sugars
decreased from 13.4 mg g-1 at day 1 to 5.8 mg g-1 at
day 6. The most significant biochemical activity during the fermentation
was the rapid and steady increase in the quantity of free amino acids
throughout the fermentation period from 43.7 mg g-1 - 70.0 mg
g-1. Proteinase activities increased from 0.51 – 0.71 U
ml-1. Alpha-amylase activities were not consistent but had
their peaks at days 1 and 3, while lipase activities were maximal at days
3 and 5 of fermentation. The role of each associated bacteria in the
fermenting okpehe indicated B. licheniformis, B. megaterium
and Bacillus subtilis as the most active bacteria involved in the
controlled fermentation without masking the fermented cotyledons after 3-6
months storage, but smoking as post fermentation treatment changed the
colour of the condiment from dark brown to black.
Adenike A.O. Ogunshe, Mopelola O. Omotosho and A.D.V. Ayansina, 2007. Microbial Studies and Biochemical Characteristics of Controlled Fermented Afiyo- a Nigerian Fermented Food Condiment from Prosopis africana (Guill and Perr.) Taub. Pakistan Journal of Nutrition, 6: 620-627.
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