Development Of A Solar Drying Unit For The Cocoa Smallholders In Malaysia
Sun drying is the most popular method used by the Malaysian smallholders to dry cocoa beans during the harvesting season. However, various limitations have been associated with this traditional practice particularly due to unpredictable weather conditions. The sun dryer is usually without any mea...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English English |
| Published: |
2003
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/11875/1/FSMB_2003_34.pdf |
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| Summary: | Sun drying is the most popular method used by the Malaysian smallholders to dry
cocoa beans during the harvesting season. However, various limitations have been
associated with this traditional practice particularly due to unpredictable weather
conditions. The sun dryer is usually without any means of protection in the event of
rain unless labour is available to look after the dryer. In situations where no other
alternatives of natural drying are available, the smallholders will either continue
using the sun dryer or sell wet beans at a lower price.
This study was carried out to develop a small-scale solar dryer to provide an
additional option to the smallholders in cocoa drying. The concept of direct solar
drying was adopted where the product is dried inside a transparent enclosure using
direct sunlight. Overall dimension of the solar dryer prototype measured 1565 mm x
912 mm x 1375 mm (L x W x H). Most of the structural components were
constructed using 'Chengal' hard wood. The side panels and drying platform were
constructed from plywood and transparent Ultra Violet Stabilised Polyethylene film
was used to form the enclosure.Air enters through the perforated platform (about 15% perforation) and the side air gaps (measuring 1365 mm x 40 mm) and the humid
air exits through the apertures (measuring 159 mm x 1565 mm) at the apex. Two
removable windows (measuring 1565 mm x 600 mm) were made at both sides of the
dryer to facilitate loading, unloading and mixing. Individual part of the prototype
was connected using bolts, nuts and screws to ease assembling and dismantling on
farm. The total material cost of construction for a unit of solar dryer was RM 156.76.
Quality of the dried cocoa beans was assessed in terms of acidity (pH and titratable
acidity), degree of fermentation (cut test and fermentation index), surface mould,
odour and sensory evaluation. The performance of the solar dryers was also assessed
in terms of bean moisture content reduction, bed and air temperatures. Two trials
were carried out to determine the effect of loading on solar drying and to compare
between the solar dryer and sun dryer. From the studies, the solar dryer is
recommended to the smallholders for 20 kg wet beans using perforated drying
platform. The performance of the solar dryer and quality of the beans showed no
significant difference (p>0.05) as compared to sun drying. This would be an added
advantage to the smallholders as protection of the beans could be achieved through
solar drying.
Based on the recommendation, the solar dryer was able to produce beans with good
external appearance, extremely light in surface mould, high in degree of fermentation
and acceptable in terms of odour and sensory evaluations. The drying period was
shorter at this loading (20 kg) which could eliminate the risk of mould growth due to
prolong drying and the beans temperatures were well below the limit detrimental to
the quality. |
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