International Journal of Marine Science, 2017, Vol.7, No.11, 96-101
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1.1.1 The solar tent dryer theory
The Solar tent dryer works through evaporative drying using the greenhouse principle (Doe, 2002). When set up
in the sun, solar energy passes through the transparent polythene but gets trapped within it thereby raising the
internal temperature (Logesh et al., 2012). Cool air flowing in through inlet vents gets heated up and moves out
moisture from fish laid on racks in the dryer through the outlet vents on the vertex.
1.2 Sample preparation
Fresh
Copadichromis virginalis
fish species were collected from cape maclear landing sites in the southern part of
Lake Malawi. The fish were thoroughly washed and arranged on the racks within the solar tent dryer and open sun
drying racks in sub samples of 400 g (Figure 3).
Figure 3 Solar tent drying (a) and Open Sun drying (b)
1.2.1 Analytical procedures
After drying, samples were packed and randomly selected for proximate, microbial analyses and sensory analyses.
1.2.2 Proximate analysis
Proximate analysis of the fish samples was done at Department of Aquaculture and Fisheries Science Laboratory
Lilongwe University of Agriculture and Natural Resources (LUANAR), Bunda Campus. The milled fish
samples
were analyzed for crude protein, crude fat, ash, moisture content, following the procedure outlined by the
Association of Official Analytical Chemists (AOAC, 2003).
1.3 Microbial analyses
A procedure earlier used by (Olokor et al., 2009) was followed for microbiological analysis of the fish samples.
Fish sample (1 g) were randomly selected from the two processing methods were blended and mixed properly in a
sterile mortar then ascetically transferred to a sample vial containing 9 mls of 0.1% sterile peptone water. The vial
was closed and shaken thoroughly for 10 minutes then allowed to stand for 20 minutes, after which a 4 fold serial
dilution was carried out in triplicates. Viable bacterial counts were enumerated in standard plate count agar after
incubation at 37°C for 48 hours. Results were reported in CFU/g.
1.3.1 Identification and enumeration of bacteria
Morphological characteristics of the various bacterial isolates in
vitro
were noted in the agar plates, and
microscopy. After staining reactions and several biochemical tests, individual microbial species were identified.
Representative isolates were re-plated on various selective media to observe their habits and specific colony
attributes.
1.4 Sensory evaluation
Sensory properties such as appearance, odor, and general acceptability of the dried samples were evaluated by 10
randomly chosen adults volunteers (age>20) using hedonic scale modified from Eyo (2001). Qualitative
descriptive analysis (QDA) of the sensory properties of the dried fish samples was done after processing. The
volunteers were asked to judge the sensory properties of the dried samples using a 5-point hedonic scale of liking.
