Comparative Study of Sun Drying and Solar Tent Drying of Hyperopisus bebe occidentalis
ABSTRACT An experiment was conducted to investigate the effect of two drying processing methods on the nutritional qualities of Hyperopisus bebe . The two methods used were solar tent dryer and traditional sun drying methods. The experimental fish were dried for 120 h (5 days). The results of proximate analysis showed significant difference (p<0.05) between the two techniques. Organoleptic evaluation showed no physical damage, no discolouration in the treatments and both had firm texture though fishes under traditional sun drying were infected by insects.
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ABSTRACT: This study was done to evaluate the drying performance, efficiency, and effectiveness of five different types of improved low-cost solar driers in terms of moisture loss from two tropical African fish species Clarias gariepinus (African sharp tooth catfish) and Oreochromis niloticus (Nile tilapia) and testing the organoleptic characteristics of the dried samples. The driers used were made from plastic, aluminum, glass, glass with black igneous stone, and mosquito net, with traditional direct open-sun drying as a control. A significant (P < 0.05) decrease in weight resulting from moisture loss in the two fish species was observed in all the driers, with the highest reduction occurring in the glass drier containing black stone. The rate of weight loss was faster in the first 4 days of drying with black stone-inserted glass drier showing the fastest drying rate with a constant weight in C. gariepinus attained on the 11th day and in O. niloticus on the eighth day. The slowest drier was plastic where a constant weight of the species were recorded on and 13th day and 11th day, respectively. Volunteers were used to assess the organoleptic characteristics of the dried samples and they showed lowest acceptability for the open-sun drying, while samples from the glass drier containing black stone had the highest acceptability in terms of the taste, flavor, appearance, texture, odor, palatability, and shelf-life. The low-cost solar driers were effective found in removing water from the fish resulting in significant loss of weight and moisture. The highest drying time, efficient performance, drying effectiveness, and high acceptability of the organoleptic parameters of the dried products from the black stone-inserted glass drier were due to the ability of the glass and the black stone to retain, transmit, and radiate heat to the fish sample all the time (day and night). These low-cost driers are simple to construct, materials for its construction readily available, easy to maintain and operate, hygienic in use, reliable, effective, occupies less area, dry products faster with increased shelf-life, save man-hour, user-friendly, use renewable energy, protect the drying samples from filthiness, wetness, and invasion by pests, insects, and microbes, with well-dried, high-quality, and better preserved final products. The adoption and use any of these low-cost solar driers by artisanal fishermen and general household in sub-Saharan Africa will not only help in reducing post catch losses, but also ensure food safety and security as there is abundant solar energy in these sub-Saharan African tropical countries for the operation of the driers.Food Science & Nutrition. 03/2014;
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ABSTRACT: Traditional sun drying methods are widely used in Bangladesh to dry fish, though the quality is not satisfactory. The aim of this study was to assess the quality of solar tunnel dried Bombay duck and Siler pomfret, and to compare it with traditional sun dried Bombay duck and Silver pomfret. Raw fish samples of Bombay duck and Silver pomfret was collected and dried using solar tunnel dryer. The quality of the dried product was analyzed measuring moisture, protein, fat, ash, peroxide value and Total Volatile Base Nitrogen (TVB-N) content and analyzing water reconstitution properties. Traditional sun dried Bombay duck and Silver pomfret were also collected from different area, and the same measurement was also performed and compared with solar tunnel dried fish samples. Microbial quality was also analyzed using standard methods. Organoleptic quality of solar tunnel dried fish samples was found very well without any objectionable flavor and odor, compared with traditional sun dried fish samples. Moisture content was also observed (15.25 % in Bombay duck and 13.43 % in Silver pomfret) within the acceptable range. Protein content of solar dried fish samples was also found higher than that of traditional sun dried samples and water reconstitution power was also found better. Peroxide and TVB-N value of the solar tunnel dried studied samples were found within the normal limit of 10-20meq/kg of oil and up to 30 mg/100gm, respectively. Aerobic Plate Count was found lower, however Salmonella and Coliform was not found in both dried samples. The quality of solar tunnel dried Bombay duck and Silver pomfret samples were of excellent compared with samples dried by traditional sun drying method.International Journal of Food Sciences and Nutrition 10/2013; 2(4):187-195. · 1.26 Impact Factor
Pakistan Journal of Nutrition 8 (7): 955-957, 2009
© Asian Network for Scientific Information, 2009
Comparative Study of Sun Drying and Solar Tent
Drying of Hyperopisus bebe occidentalis
R.O. Ojutiku, R.J. Kolo and M.L. Mohammed
Department of Water Resources, Aquaculture and Fisheries Technology,
Federal University of Technology, Minna, Niger State, P.M.B 065, Nigeria
Abstract: An experiment was conducted to investigate the effect of two drying processing methods on the
nutritional qualities of Hyperopisus bebe. The two methods used were solar tent dryer and traditional sun
drying methods. The experimental fish were dried for 120 h (5 days). The results of proximate analysis
showed significant difference (p<0.05) between the two techniques. Organoleptic evaluation showed no
physical damage, no discolouration in the treatments and both had firm texture though fishes under
traditional sun drying were infected by insects.
Key words: Traditional sun drying, solar tent, Hyperopisus bebe
Fish is a highly nutritious food and it is particularly
valued for providing protein of high quality better than
those of meat and egg. However, it is one of the most
perishable of all the foods because it is a suitable
medium for growth of micro-organisms after death.
Igene (1983) found that in the tropics at ambient
temperature, spoilage is rapid; fish will spoil within 12-
20 h depending on species, method of capture. As soon
as fish is caught and dried, certain irreversible spoilage
begin to take place, leading to spoilage and
deterioration (Conne, 1995) and most subsequent
processing or preservation operation are intended to
prevent these causes or usually reduce the rate at which
they proceed (Eyo, 1986).
Sun drying is one of the traditional methods employed to
preserve fish. It has been observed as the most
convenient and cheapest form of preservation in Nigeria
(Eyo, 1986). The need to use solar radiation/energy for
fish drying has become even more than necessary at the
present time because of the huge competitive demand
for fuel wood for fish smoking. Solar drying is an
improved method of sun drying. It minimizes or stop
some of the limitations of open sun drying. It differs from
open sun drying in that a structure, often very simple in
construction is used to enhance the effect of the
insulation due to the fact that solar tent dryer is an
enclose structure that traps heat inside the tent and
make effective use of the heat which is stored inside the
tent both in the day and night by the help of some rocky
stones which are painted black to absorb heat.
Hyperopisus bebe occidentalis is the sole specie of
genus Hyperopisus. It has a small rayed fin situated well
to the rear of the body. This specie inhabits in both rivers
and swamps and is one of the most common momyrids
the commercial catches.
This study assessed and compared the organoleptic
and proximate composition of solar tent dried fish and
open sun dried fish.
MATERIALS AND METHODS
The design of the solar tent dryer is based on
horticultural green house. It consists of a plastic
polythene sheet stretched over a wooden frame work (3
feet wide by 4 feet long by 4 feet high) with side and top
vent (1 by 1 feet) and the fish rack (1.5 feet by 1.5 feet)
were placed with wire mesh under and underneath were
painted rocks which was used as a heat collector and
Sun drying rack was constructed by placing sack on a
concrete floor and a wooden frame work was
constructed from chicken wire mesh which was used to
cover the sack that is placed directly under the sun for
maximum utilization of the sun.
The experimental fish (Hyperopisus bebe) used for the
experiment were purchased and transported to the
laboratory for further analysis. They were washed and
manually operated by descaling and gutting was carried
out. The gutted fish were arranged on the tray within the
solar tent dryer (treatment B) and open sun drying
Proximate analysis was carried out on the fresh fish
before the experiment and on the experimented fish
every 24 h for 5 days. The analysis was done using the
method of AOAC, 1980. The parameters measured were
crude protein, ash, crude fibre, moisture content, lipids.
Organoleptic assessment was also carried out using a
Table 1:Fresh proximate composition of Hyperopisus bebe
Pak. J. Nutr., 8 (7): 955-957, 2009
Table 2: The daily proximate composition of crude protein, lipid, ash and crude fibre
Day 1 (24 h)3.36±3.39±3.70±
Day 2 (24h)3.15±2.88±3.99±
Day 3 (24 h)2.02±1.74± 6.68±
Day 4 (24 h)0.28± 0.29±8.36±
Day 5 (24 h)0.12±0.23±6.26±
Hedonic scale grading base on method of Doe and
Olley (1990). Analysis of variance was used to
statistically test the results.
discolouration was observed in the treatments. The
texture of the two treatments was also observed to be in
good condition throughout the experiment.
Bacteria infestation was observed in treatment B which
was the traditional sun drying method during the first
and second day of the experiment.
throughout the experiment. Also, no
The proximate analysis of the fresh Hyperopisus bebe
were 74% moisture, 29.96% crude protein, 1.57% ash
and 0.2% crude fibre (Table 1)
The daily proximate composition of crude protein, lipid,
ash and crude fibre analyzed were increasing in the two
treatments (A and B) from the first day to the last day of
the drying process i.e. fifth day (Table 2). The highest
protein was recorded treatment B which is the solar tent
dryer with a value of 62.5% on the fifth day while
treatment A which is traditional sun drying was 59.8% in
the fifth day. There was no significant difference (p>0.05)
among the days of the experiment but significant
difference (p<0.05) was observed between the
The moisture content range of the treatment B was 65%
in the first day to 10% in the fifth day while treatment A
was 69-11.5% in the last day (Table 2). Significant
difference (p<0.05) was observed between the
Table 2 also shows the lipid composition of the two
treatments. The lipid concentration of traditional sun
dried fish ranged between 30.2% in the first day to
28.30% In the fifth day while solar tent dried fish ranged
was 29.4% In the first day and 26.50% in the last day of
the experiment. Significant difference was also observed
The ash content of the experimented fish is also
presented in Table 2 which ranged between 2.50-11.1%
in the fifth day I treatment A and 0.5-1.94% in treatment
B and significant difference (p<0.05) was observed.
The crude fibre of the two treatments increased from the
first day to the last day (Table 2). Traditional sun dried
ranged from 0.5-1.94% in the fifth day while solar tent
dried (treatment B) ranged from 0.3% in the first day to
2.4% in the fifth day. Significant difference (p<0.05) was
also observed between the treatments (Table 2).
The organoleptic evaluation
appearance of the two treatments were in good
Conclusion: From this study, the solar tent dryer has
proven to be more efficient and reliable form of fish
preservation and processing using the ambient solar
energy. The products were of good quality compare to
sun drying in terms of nutritional value and hygienic
showed that the
The moisture content of both treatment A and B reduced
from 74-11.5% and 10% respectively which agreed with
Clucas (1982). Clucas (1982) reported that a fish well
dried or moisture content reduced to 25% will not be
affected and if further dried to a moisture content of 15%,
the growth of mould will cease and increase the shelf
The protein content of the experimented fish was
23.33% which increased to 59.8% and 62% in treatment
A and B respectively. This agrees with Cowey and
Sargent (1972) who reported that as moisture content of
fish reduces, the protein content increases. They further
observed that the crude protein in fish is between 50%
and 70% which agrees with this finding.
The lipid content of this fresh fish was 29.96% which
agrees with the findings of Conne (1995) who reported
that lipid content of fish varies from lean fish to fatty fish.
The reported that fatty fish is between 21-30% and could
be above and Hyperopisus bebe is a fatty fish. The lipid
content reduced to 28.50 and 26.50% in treatment A and
The ash content of the fresh Hyperopisus bebe was
1.57% which increase to 11.1% in treatment A and
9.40% in treatment B. This finding agrees with Tunison
et al. (1990) who observed ash content to be between
2.50 and 4.60%.
Pak. J. Nutr., 8 (7): 955-957, 2009
It was also discovered that an average fisher man/fish
farmer can own a solar tent dryer in his/her farm with just
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Igene, J.O., 1983. Drying of fish, factors to consider.
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E.O. Rodgers, 1990. The nutrition of trout. Res. Bull.
Association of Official Analytical Chemistry (AOAC),
1980. Method of analysis (W. Hortwhz Ed) 13 Ed.
AOAC Washington D.C., 129-146.
Clucas, I.J., 1982. Present fish drying techniques in
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F.A.O., F.J. Zam (73/00/3 FAO), 25 p.
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