Genomics and Applied Biology, 2017, Vol.8, No.3, 17-25
21
The percentage oil content result shows that the initial oil content before fermentation was lower than the oil
contents of all the treatments and control experiment after the fermentation period elapses. The highest and lowest
oil contents of 19.87 and 17.84 % were recorded in the
L.
plantarum
and
S. exguus
’s treatments. More so, there
were significant differences among the treatment.
The ash content of the control experiment (4.43) was higher than those of the treatments after fermntation. Mixed
microbes treatment produced the least amount of ash of 1.79 which not significantly different from the ash content
of the
G. candidum
’s treatments after 96h of fermentation. The highest and lowest fibre contents of 4.14 and 1.80
were observed in the control experiment of the control experiment and
G. candidum
’s treatment respectively
(Table 6).
Table 6 Proximate analysis of wet cassava peels before and after 96 hours fermentation
Treatments
Carbohydrate
Protein
Oil
Ash
Fibre
Value before fermentation
67.17 ±0.00
g
20.78 ±0.01
a
6.33 ±0.00
a
3.72 ±0.03
d
2.00 ±0.00
c
Control
52.77 ±0.01
d
25.32 ±0.01
f
13.34 ±0.47
b
4.43 ±0.07
e
4.14 ±0.01
d
Lactobacillus
plantarum
48.13 ±0.01
a
26.83 ±0.01
g
19.36 ±0.02
e
2.16 ±0.10
c
3.32 ±0.02
e
C. manihot
51.44 ±0.01
b
24.14 ±0.03
d
18.69 ±0.04
d
1.95 ±0.02
b
3.89 ±0.01
f
S. exguus
54.22 ±1.19
e
23.53 ±0.03
b
17.84 ±0.00
c
2.31 ±0.02
c
2.10 ±0.01
d
G. candidum
54.48 ±1.01
f
23.31 ±0.02
c
18.53 ±0.02
d
1.88 ±0.12
ab
1.80 ±0.03
a
Mixed microbes
51.78 ±1.99
c
24.67 ±0.00
e
19.87 ±0.02
f
1.79 ±0.01
a
1.89 ±0.01
b
Note: Each value is Means ±Standard deviation of three replicates. Values followed by the same letter in the same column are not
significantly different using Tukey’s Test at * (P < 0.05); NB: The control represents the proximate analysis of the un-inoculate wet
peels after 96 hours
2 Discussion
The results of this research showed that
Lactobacillus
plantarum
,
Corynebacterium manihot, Geotricum
candidum
and
Saccharomyces exguus
were the common microorganisms responsible for the fermentation of
cassava. These microorganisms (
L.
plantarum
,
C. manihot, G. candidum
and
S. exguus
) isolated from the waste
water of fermented cassava pulps have been earlier isolated by various researchers (Okafor, 1977; Essers et al
.
,
1995; Amao-Awua et al
.
, 1996; Kobawala et al
.
, 2005). Moreover, these bacteria (
L.
plantarum
, and
C. manihot
)
and yeasts (
G. candidum
and
S. exguus
) have been reported to be the main fermenting microorganisms of cassava
(Ahaotu et al., 2013). All the microorganisms except
Saccharomyces exguus
, isolated and used for the study have
been identified as linamarase (an enzyme capable of converting cyanogenic glucoside to free cyanide and glucose)
producing microorganisms (Ahaotu et al., 2013). Kimaryo et al. (2000) and Oyewole and Odunfa (1990) have
reported that linamarase produced by microorganisms contribute to the process of detoxification of cassava pulp
during fermentation.
The result also showed that, after 96 hours of fermentation, the linamarin content of the fermented cassava peels
was very low. Cardoso et al. (2005) reported that the combination of wetting, fermentation and drying can reduce
cyanide contents up to 99%. The increase in residual cyanide in all the treatments as the period of fermentation
increased showed that more cyanides were released by breaking down linamarin (cyanoglucoside) through the
process of fermentation.
Also, fermenting cassava peels was noted to cause an increase in the titratable acidity of the peels. This however
may be due to the increase in the lactic acid content of the fermented peels and the release of residual cyanide
which is acidic in nature. Lactic acid has been reported to be produced during fermentation of cassava for garri
production and it (lactic acid) amount has been taken as an index of garri quality and it (lactic acid) content is
dependent on the period of fermentation of the garri (Achinewhu and Owuamanam, 2001).
