Genomics and Applied Biology, 2017, Vol.8, No.3, 17-25
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The rates of fermentation were observed to be faster in the treatments than the control when the linamarin values
obtained between 0 and 96 h of fermentation were compared. Nevertheless, no significant difference was observed
in the mean value of linamarin among all the treatments and control experiments at 96 hours of fermentation by
Tukey’s Test at P < 0.05 (Table 2).
1.4 Residual cyanide (mgHCN/kg) obtained during fermentation of milled cassava peels
The residual cyanide which is the quantity of liberated cyanide from the linamarin increased as the days of
fermentation increased in all the treatments and control experiment. Nevertheless, this was not the case at 96
hours of fermentation: the residual cyanide decreased in all the treatments except the mixed culture treatment
which had a slight increment from 59.77 mgHCN/kg to 60.33 mgHCN/kg.
S.
exguus
had the least residual
cyanide of 55.90 mgHCN/kg while
L. plantarum
had the highest value (of linamarin) of 57.87 mgHCN/kg at the
onset of fermentation. Notwithstanding, no significant difference was noted in the mean values of residual cyanide
of all the treatments and control at the commencement of fermentation when Tukey’s mean separation test at P <
0.05 confidence level was used to separate the mean value. At 96 hours of fermentation, the least value of residual
cyanide of 59.77 mgHCN/kg was recorded in the control experiment whereas the highest value was observed in
the
L. plantarum
treatment (Table 3).
Table 3 Residual cyanide (mgHCN/kg) obtained during fermentation of milled cassava peels
Fermenting Organism
Residual cyanide (mgHCN/Kg) values obtained during fermentation / period of fermentation (Hours)
0
24
48
72
96
Control
57.87 ±3.96
59.43 ±5.37
59.97 ±5.77
59.97 ±5.77
59.77 ±5.61
Lactobacillus
sp
55.90 ±2.31
59.77 ±5.60
59.97 ±5.77
62.10 ±7.62
62.10 ±7.60
C. manihot
.
55.90 ±2.30
57.66 ±3.78
57.77 ±3.87
58.00 ±4.09
58.00 ±4.09
S. exguus
57.44 ±3.60
60.00 ±5.77
61.67 ±7.30
60.31 ±6.06
60.20 ±5.90
Geotrichum candidum
57.20 ±3.48
59.63 ±5.51
61.20 ±6.84
61.67 ±7.30
60.00 ±5.77
Mixed microbes
58.03 ±4.10
57.77 ±3.87
59.53 ±5.43
59.77 ±5.60
60.03 ±4.35
Note: Each value is Means ±Standard deviation of three replicates. Values in the same column are not significantly different using
Tukey’s Test at * (P < 0.05)
1.5 Total titratable acidity obtained during fermentation of milled cassava peels
The result of the titratable acidity (TA) is shown on Table 4. The TA increases as the period of fermentation
increases. At the beginning of fermentation,
G. candidum
had the highest amount of TA which was 6.80%. This
value (6.80%) is significantly different (P < 0.05) from the TA produced by other treatments and control
experiment all at the onset of fermentation. Moreover, the control experiment,
L. plantarum
and the mixed
microbes’ treatments did not show any significant difference (P < 0.05) in TAs of 0.58% and 0.52% respectively
produced at the point of inoculation, but they were significantly different from TA of 0.68% and 0.52%
respectively produced by
G. candidum
and
L.
plantarum’s
treatments. It was also observed that TA increased more
rapidly between 0 and 24 hours. The highest increment in TA (0.42 to 0.88%) between 0 and 24 hours of
fermentation was recorded in the
S. exguu’s
treatments which was 47.73% increment. More so, at 24 hours of
fermentation, mixed microbes treatment produced the lowest TA of 0.58%. At 48h of fermentation, Control,
L.
plantarum
and mixed microbes’ treatments produces TAs of 1.3, 1.3 and 1.22% respectively although these values
were not significantly different from each other at P < 0.05.
At 72 hours of fermentation, all the treatment except control and mixed culture showed significant differences in
the amount of TA produced.
L.
plantarum
treatment produced the highest TA of 22.20 % at this instance (72
hours of fermentation). At 96 hours of fermentation,
C. manihot
produced the least amount of TA, 12.20 % which
was significantly different from the TAs produced by all the other treatments, however,
L.
plantarum’s
treatment
produced the highest amount of TA of 22.26 % (Table 4).
