International Journal of Marine Science, 2017, Vol.7, No.11, 96-101
100
drying period is not going to be lost. The study echoed results by Gokoglu
et al
.
(2004) who reported that increase
in crude protein content after drying is due to dehydration which increases the nutritional value of fish. Solar tent
dried
Copadichromis virginalis
had low moisture content than open sun dried. Fish spoilage has shown to be a
function of moisture content. The total amount of body water of fish species, depend on morphological and
chemical differences, physical properties and the fish storing. Dried fish with moisture level of 6 to 8% retards the
rate of microbial spoilage as the water activity is reduced during storage hence increasing the shelf life. Oparaku
et al. (2010) indicated that products with high moisture content above 35% are susceptible to attack by flies that
result to development of maggots during storage. Low levels of moisture was achieved for products from solar
tent dryer than in the open sun dried fish products. This was due to high temperatures and low humidity associated
with solar tent drying that created an ideal condition in drying of fish than open sun drying which had low
temperature and high relative humidity (Table 4). This suggests that high relative humidity
had minimal influence
in drying of fish on the racks as it limits the amount of water the air can absorb. In their study (Sablani, 2003)
reported that dryers that give low moisture content have lower humidity and higher temperatures inside the drying
units.
Table 4 Meteorological data
Environmental factor (Average
）
Solar tent dried
Open sun dried
Temperature (
o
C)
31.3
20.2
Relative Humidity (%)
58.1
76.8
Wind speed (m/s)
1.8
1.8
Rainfall (mm)
0
0
Results of microbial analysis are shown in Table 3. Total Viable Counts for solar tent dried and open sun dried
Copadichromis virginalis
were 2.5×10
2
and 4.1×10
5
respectively. In all fresh samples, the microbial population
was 3.0×10
2
. The results is an indicative of possible contamination. This observation was validated by analyses
and isolation of pathogens and spoilage flora in open sun dried fish.
Escherichia coli
,
Psuedomonas
,
Salmonela
,
Shigella
and
Vibrio
were detected in worrying concentrations in open sun dried
Copadichromis virginalis
.
However they were totally absent in solar tent dried
Copadichromis virginalis
dried samples. These pathogens are
associated with food toxiinfections and are indicators of very poor hygienic quality of the processing method
(Huany et al., 2010). These bacteria are probably from soil, human and animal origin and have contaminated Lake
water (Oramadike, 2009). This clearly shows microbial contamination by pathogens for open sun dried fish may
be considered as an important warning signal for human consumption. Consequently, it is imperative that
measures are taken to promote use of solar tent dryers as a hygienic processing technology to dry small fish.
Appearance and colour in this study appeared to be the two most important parameters which influenced panel’s
preference for dried fish products. The preference was confirmed to a greater extent by scores for overall
acceptability which were also high than open sun dried. In their study, Reza et al. (2009) reported that solar tent
dried fish gave superior quality. In this regards, if a value added fish product can have high scores during
organoleptic assessment then the possibility of acceptance for the products at the market is there. The significant
difference in the overall acceptability score apparently indicated that solar tent drying produced the desirable
effect. This observation agrees with the sensory evaluation done on fish dried by open-sun drying and low cost
solar driers by Sengar et al. (2009). Hence, use of solar tent drying is more effective and has more acceptability in
terms of organoleptic properties than open-sun drying.
4 Conclusion
The study findings have shown that solar tent dryer have a potential in maintaining quality of processed fish. As
such, the use of solar tent dryers can help in strengthening of the fisheries value chain by not compromising
product quality during processing as well as building capacity among fisherfolks to adapt to climate change by
reducing adverse pressure on natural resources such as removal of forests for fuel wood so that the potential role
of fish in improving nutrition security in Malawi is enhanced.
