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International Journal of Aquaculture, 2014, Vol.4, No.21 123
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130
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124
objectives of this study were to evaluate the effect of
different concentrations of salt and pepper spice
mixture on the microbial, physical, organoleptic and
nutritional quality of smoked catfish during 18-week
storage at room temperature.
1 Results
1.1 Proximate composition of smoked
C. gariepinus
treated with salt and pepper spice mixture
There was a decrease in the protein level in the final
proximate composition (18 weeks) when compared
with the initial (after 24 hours smoking). Although,
the values were significantly different (p <0.05)
among the treatments. The highest crude protein
was recorded in treatment 5 while the least was in
control. Also, high moisture content was recorded in
all the treatments at 18 weeks compared to the
values obtained after 24 hours smoking (Table 1).
1.2 Biochemical composition of
C. gariepinus
The biochemical composition: Peroxide value (PV),
Thiobarbituric acid (TBA mg/kg); Free fatty acid
(FFA mgKOH/g) and Total Volatile Base (TVB
mg/100g) showed an increase in all the sample
determined, increased in values were observed as
the storage period increased; the highest values was
recorded in the control sample ( 2.39, 0.39, 7.27,
6.16; 4.31, 0.62, 8.93, 12.65; 13.35, 2.25, 14.86,
21.33; 32.00 3.15 28.85, 44.14) for 24 h after
smoking, 6, 12 and 18 weeks respectively while the
least in 20% spiced mixture of pepper and salt (2.05,
0.2, 3.89, 4.57; 3.58, 0.31, 2.44, 5.09; 4.13, 0.44,
4.80, 6.29; 10.91, 0.95, 6.19, 12.91) respectively
(Table 2).
Table 2 Biochemical composition and microbial analysis of smoked
C. gariepinus
with different concentration of preservatives
Duration
Parameter
Control
E2
E3
E4
E5
After 24 h
PV
2.39±0.01d
2.24±0.00c
2.18±0.02bc
2.10±0.00ab
2.05±0.01a
TBA
0.39±0.00d
0.34±0.02c
0.29±0.01b
0.26±0.01b
0.20±0.00a
FFA
7.27±0.03d
5.94±0.02c
5.00±0.01b
4.61±0.01ab
3.89±0.00a
TVB
6.16±0.01e
5.75±0.00d
5.40±0.00c
5.18±0.03b
4.57±0.00a
6 weeks
PV
4.31±0.00e
4.13±0.00d
3.99±0.02c
3.88±0.01b
3.58±0.03a
TBA
0.62±0.01d
0.58±0.02cd
0.51±0.00c
0.39±0.01b
0.31±0.00a
FFA
8.93±0.00e
5.35±0.01d
4.84±0.01c
3.59±0.02b
2.44±0.02a
TVB
12.65±0.00e
8.82±0.00d
7.62±0.02c
6.29±0.01b
5.09±0.002a
12 weeks
PV
13.35±0.02e
9.38±0.03d
7.21±0.00c
5.96±0.01b
4.13±0.00a
TBA
2.25±0.00e
1.45±0.00d
0.86±0.01c
0.64±0.01b
0.44±0.01a
FFA
14.86±0.00e
11.90±0.01d
7.68±0.01c
5.40±0.00b
4.80±0.00a
TVB
21.33±0.00e
15.26±0.02d
11.50±0.02c
8.46±0.03b
6.29±0.03a
18 weeks
PV
32.00±0.00e
23.85±0.00d
18.95±0.01c
13.09±0.02b
10.91±0.02a
TBA
3.15±0.01e
2.03±0.00d
1.77±0.01c
1.09±0.01b
0.95±0.02a
FFA
28.85±0.00e
19.92±0.00d
13.50±0.02c
9.91±0.03b
6.19±0.02a
TVB
44.14±0.00e
32.22±0.01d
19.88±0.01c
15.35±0.02b
12.91±0.00a
Note: Keys: E
1
= smoked fish without spice (control) E
2
=smoked fish with 5% spice; E
3
= smoked fish with 10% spice; E
4
=smoked
fish with 15% spice and E
5
=smoked fish with 20% spice. Peroxide value (PV), Thiobarbituric acid (TBA mg/kg); Free fatty acid
(FFA mgKoH/g) and Total Volatile Base (TVB mg/100g)
1.3 Organoleptic assessment of smoked
C. gariepinus
with different concentration of salt and pepper
spice mixture
The organoleptic assessment of
C. gariepinus
24
hours after smoking compared to the values recorded
at 6, 12 and 18 weeks indicated a decrease in
appearance, quality, texture, odour, flavour and taste
(overall acceptability) as the storage period increased.
The highest overall acceptability was obtained in 20 %
spice mixture of salt and pepper (6.72, 5.80, 4.91, 4.15)
at 24 h after smoking, 6, 12 and 18 weeks respectively
while the least in control (6.49, 4.91,4.07, 3.03) at 24
h after smoking, 6, 12 and 18 weeks respectively
(Table 3).
1.4 Microbial analysis of smoked
C. gariepinus
with
different concentration of salt and pepper spice
mixture
Increasing values were recorded in total viable count
among the treatments with highest values in control