International Journal of Aquaculture, 2018, Vol.8, No.15, 112-120
116
Table 4 Effects of storage on the heavy metal concentrations (mg/kg) of
Sarotherodon galilaeus
from the two locations
Location
Heavy Metals
(mg/kg)
Week 1
Week 6
S1
S2
D1
D2
S1
S2
D1
D2
Asejire
Pb
0.007
f
0.016
a
0.009
c
0.014
b
0.006
g
0.013
c
0.009
c
0.011
a
Cd
0.007
c
0.008
b
0.009
a
0.009
a
0.006
d
0.007
c
0.007
c
0.008
b
Ni
0.015
c
0.018
a
0.010
g
0.014
d
0.012
e
0.017
b
0.010
f
0.012
e
As
0.006
b
0.007
a
0.006
b
0.006
b
0.005
c
0.005
c
0.004
d
0.005
c
Opa
Pb
0.015
a
0.013
b
0.013
b
0.013
b
0.010
d
0.011
c
0.013
b
0.009
e
Cd
0.008
c
0.010
b
0.009
c
0.011
a
0.008
d
0.010
b
0.010
b
0.011
a
Ni
0.022
a
0.022
a
0.019
c
0.018
d
0.018
d
0.020
b
0.020
b
0.015
e
As
0.004
c
0.003
d
0.004
c
0.002
d
0.005
b
0.004
c
0.006
a
0.005
b
Note: Standard Deviation for all means (average of three determinations) ranged from ±0.0000 to ±0.0006; mean values within each
row bearing similar superscripts are not significantly different (
p
>0.05); S1=Smoked unsalted, S2=Smoked salted, D1=Dried
unsalted, D2=Dried and salted
Table 5 Effects of storage on the heavy metal concentrations (mg/kg) of
Tilapia zillii
from the two locations
Location
Heavy Metals
(mg/kg)
Week 1
Week 6
S1
S2
D1
D2
S1
S2
D1
D2
Asejire
Pb
0.015
b
0.016
a
0.008
e
0.009
d
0.009
d
0.012
c
0.008
e
0.008
e
Cd
0.014
a
0.013
b
0.012
c
0.013
b
0.012
c
0.010
e
0.011
d
0.012
c
Ni
0.021
a
0.019
b
0.019
b
0.018
c
0.018
c
0.016
e
0.017
d
0.017
d
As
0.007
a
0.006
b
0.005
c
0.005
c
0.006
b
0.005
c
0.005
c
0.005
c
Opa
Pb
0.017
a
0.015
b
0.017
a
0.014
c
0.010
e
0.011
d
0.011
d
0.010
e
Cd
0.016
b
0.017
a
0.014
d
0.015
c
0.011
g
0.012
f
0.013
e
0.013
e
Ni
0.025
b
0.024
c
0.026
a
0.023
d
0.022
e
0.023
d
0.019
f
0.022
e
As
0.007
b
0.005
d
0.006
b
0.004
d
0.005
c
0.006
b
0.005
c
0.005
c
Note: Standard Deviation for all means (average of three determinations) ranged from ±0.0000 to ±0.0006; mean values within each
row bearing similar superscripts are not significantly different (
p
>0.05); S1=Smoked unsalted, S2=Smoked salted, D1=Dried
unsalted, D2=Dried and salted
Table 6 Effects of storage on the heavy metal concentrations (mg/kg) of
Clarias gariepinus
from the two locations
Location Heavy
Metals (mg/kg)
Week 1
Week 6
S1
S2
D1
D2
S1
S2
D1
D2
Asejire
Pb
0.017
a
0.016
b
0.010
e
0.009
f
0.013
d
0.014
c
0.009
f
0.009
f
Cd
0.011
b
0.012
a
0.008
d
0.009
c
0.009
c
0.011
b
0.008
d
0.009
c
Ni
0.018
b
0.019
a
0.015
d
0.015
d
0.016
c
0.018
b
0.014
e
0.012
f
As
0.005
a
0.003
c
0.004
b
0.005
a
0.005
a
0.004
b
0.004
b
0.005
a
Opa
Pb
0.009
a
0.008
b
0.007
c
0.006
d
0.008
b
0.008
b
0.007
c
0.006
d
Cd
0.013
a
0.013
a
0.010
c
0.011
c
0.011
c
0.012
b
0.009
e
0.010
d
Ni
0.017
a
0.015
b
0.015
b
0.014
c
0.015
b
0.013
d
0.012
e
0.013
d
As
0.003
a
0.002
b
0.003
a
0.003
a
0.002
b
0.002
b
0.002
b
0.003
a
Note: Standard deviation for all means (average of three determinations) ranged from ±0.0000 to ±0.0006; mean values within each
row bearing similar superscripts are not significantly different (
p
>0.05); S1=Smoked unsalted, S2=Smoked salted, D1=Dried
unsalted, D2=Dried and salted
3.1 Changes in the moisture content during storage
Figure 1, Figure 2, Figure 3 and Figure 4 present the changes in the moisture contents during storage. The
smoking, drying and salting processes resulted in significantly reductions in all the samples. Moisture content
reduction during processing is advantageous; it reduces the fish susceptibility to microbial spoilage, oxidative
decomposition of polyunsaturated fatty acid, and consequently improves the quality of the fish and also extend the
shelf life (Frankel, 1991; Bassey et al., 2014). Moisture content increased during the storage of the samples.
Throughout the storage period, all samples had moisture contents that could be regarded as shelf stable (<25%).
