Solar Drying: Fundamentals,Applications and Innovations - National ...

Bala and Hossain - Solar Drying of Fishery Products
60
Collector outlet temperature,
50
40
30
20
10
0
100 200 300 400 500 600
Solar radiation, W/m 2
Figure 4.8. Air temperature at the outlet of the collector as a function of solar radiation
Solar tunnel driers have been widely tested in the fields in Bangladesh for drying of
fish. The typical drying curves of three different types of fish in solar drier and those
dried in the sun are shown in Figure 4.9 to Figure 4.11. Figure 4.9 shows that drying in
the solar tunnel drier required 3 days to dry silver Jew fish from 74.45% (wb) to 14.29%
(wb) as compared to 74.4% (wb) to 20.29% (wb) in 3 days in traditional sun drying.
Moisture content, %
80
70
60
50
40
30
20
10
0
Sample
Control
0 5 10 15 20 25 30
Drying time, hr
Figure 4.9. Moisture content profile during solar drying of silver Jew fish
Figure 4.10 shows that drying in the solar tunnel drier required 3.75 days to dry
ribbon fish from 73.03% (wb) to 14.19% (wb) as compared to 73.03% (wb) to 23.46%
(wb) in 3.75 days in traditional sun drying while Figure 4.11 shows that drying in the
solar tunnel drier required 1.5 days to dry Bombay duck from 90.32% (wb) to 13.73%
(wb) as compared to 90.32% (wb) to 26.04% (wb) in 1.5 days in traditional sun drying.
There was considerable reduction in drying time of fish in solar tunnel drier and
there was no difference in drying rate at different positions of solar tunnel drier. The
solar dried fish was better in terms of color, texture, taste and flavor.
104 Drying of Foods, Vegetables and Fruits