Collaboration for Agriculture and Rural Development
(CARD)
Program
118
COCOA DRYING USING SOLAR DRIER
Project title:
Cocoa fermentation, drying and quality assessment in Vietnam
P
roject
c
ode
: CARD 013/05VIE
Author
s:
Nguyen Van Thanh
1
, Huynh Xuan Phong
1
, Neil Hollywood
2
and Ha Thanh Toan
3
Project implementi
ng organizations:
1
Biotechnology Research and Development Institute, Can Tho University, Vietnam
2
Queensland Department of Primary Industries and Fisheries, Australia
3
Can Tho University, Vietnam
SUMMARY

countries are Côte d’Ivoire, Ghana, Nigeria,
and Cameroon. Pacific Asia area accounts for
about 15% and America is 13% of 3.5 million
tons cocoa beans in over the world (Phuoc,
2006). According to the ICCO, the world will
be lack about 102,000 tons cocoa bean in 2010
-
2011 because of the decreasing
of cocoa bean
in 2008
-
2009 crops. There are some reasons
that lead to decrease cocoa production are
insecurity politics, natural calamity, old and
stunted cocoa tree, lack of land in some main
cocoa producing countries. For some nine
decades, global coc
oa production has increased
steadily and consistently to keep with the ever
-
increasing needs for cocoa bean. Consumption
has increased on average by 3.5% per annum
over recent years and is projected to increase
by 1.5
-
3.5 per annum over the coming 5 year
s
(Knight, 1999).
In 1998, the Ministry of Agriculture and Rural
Development carried to investigate cocoa tree

Vietnam, sun drying is the
main method to dry cocoa beans. This is a very
simple method and the most effective to drying
of cocoa bean. This allows acids in the cocoa
to evaporate off and produce a low acid, high
cocoa flavoured product. However, in the
un
favourable condition of the weather,
especially in the wet season, the drying takes
longer, cocoa may will be over fermentation
and mould contamination that can produce
some off
-
flavours and lead to down
-
grading of
the cocoa.
One on many major activities
of the scientific
project “Cocoa Fermentation, Drying and
Quality Assessment in Vietnam” is apply and
test the solar drier for cocoa drying. The solar
drier has be studied, constructed, and improved
by the Cocoa Research team between
Queensland Department
of Primary Industries
and Fisheries, Australia and Biotechnology
R&D Institute, Can Tho University (CTU).
Solar driers have a drying bed in center and
two beside right triangle wings. They uses

4m
2
drying bed that can satisfy to smallholder
requirements and lower price was improved,
constructed and tested.
Nguyen Van Thanh, Huynh Xuan Phong, Neil Hollywood & Ha Thanh Toan
120
The results demonstrate similar drying rates
for the large and smaller dryer. Figure 2 shows
that the temperature in two drie
r is almost the
same and always higher than ambient. In all
drying time, the humidity in solar drier is
always lower than ambient. Moisture loss is
the same rate in all eight treatments and
reached to desire moisture only 4 to 6 days
(Fig. 3).
The project
has conducted at Can Tho
University, Nong Lam University, Western
Highlands Agricultural Science Institute,
smallholders in Can Tho, Ben Tre, and Dak
Lak provinces for 2 years. These institutions
have cocoa research group and these provinces
are the major
area producing cocoa in
Vietnam. In 2007, there were eight solar driers
were constructed and tested at these
institutions and smallholders. Some main
results achieve as follow:

used in whole year, more effectively in the wet
season because that time is also major flush in
cocoa production.
Cocoa beans were dried continuous not only
on day time but also on night. Therefore, cocoa
beans can be avoid over fermentation (rotten
Temp & RH25/4/06
0
20
40
60
80
100
120
00:00
0
1
:0
0
0
2
:0
0
0
3
:0
0
0
4
:

1
7
:0
0
18
:
00
19:00
20:00
21:00
22:00
2
3
:0
0
Tim e of day
T em p & R H
Temp Dryer
RHDryer
Temp Ambient
RHAmbient
Fig. 4
Temp.
encountered in sun
dry
with and without solar
drier
Fig.
5
T

8
2
0
2
2
2
4
Time of day
Temperature
Solar drier
Sun drying
Ambient
Fig
. 2
Conditions of temperature and
R
H%
in dr
i
er compared to ambient
Fig. 3
Dryi
ng rate of cocoa in the solar
dri
er
T emp and RH of D r yer s
20
30
40
50

5
6
D ay o f drying
F2T2R2 Big Dryer
F2T2R2 Small Dryer
F2T4R2 Big Dryer
F2T4R2 Small Dryer
F2T2R3 Big Dryer
F2T4R3 small Dryer
F2T4R3 Big Dryer
F2T4R3 small Dryer
CARD 013/05 VIE
–
Cocoa fermentation
and drying
12
1
stag
e) and reduce mould contamination. These
are very important because over fermentation
and mould contamination can produce some
off
-
flavours and lead to down
-
grading of the
cocoa and buyers will pay less for it.
Using cocoa solar drier is decrease gre
atly
drying surface on the same quantity of

0
1
2
3
4
5
6
7
Day of drying
% m oisture
Dry weather
Wet weather
Moisture loss
0
10
20
30
40
50
60
70
0
2
4
6
8
Day of drying
M oistu re
Solar drier
Sun drying

clear area, s
o that the driers can receive
maximum energy of sunshine. Moisture in
solar drier is easy to evaporated and removed
stagnant water that can be drop back
(especially in the morning) to dried cocoa
beans. This assists to reduce the erosion of
metals by high
acidity water evaporated from
fermented cocoa beans. Driers should be
placed in South
-
North direction because two
wings can receive equal and full energy from
sunshine all day. Polycarbonate roofs are
cleaned frequently because clean roofs can
receive mo
re effectively energy and sunshine.
In wet season, solar drier could be jointed with
2
-
4 filament lamps (100W/220V) to increase
drying rate (need only in long
-
time
rainstorms).
3
.
Conclusion
Base

cocoa, and increase income of smallholders.
Moreover, employees in rural areas are
lack
for plant, harvest and pre
-
processing at that
time. This also takes part in hasten to
mechanize and apply the progressive science
and technology in agricultural works. Because
of special requirements of cocoa drying
process, the solar driers can reso
lve the
problem of cocoa drying, especially in the
unstable of the weather conditions and long
time, heavy rain. Wet season is also the major
harvest of cocoa in Mekong delta as other
provinces in Vietnam.
References
1.
Hollywood, N., Brown S., and Toreu B.
,
1997,
A Design for improved efficiency
in the solar drying of cocoa
.
2.
Hollywood, N., Ha Thanh Toan
and
Nguyen Van Thanh, 2008
. Cocoa

–
Cocoa fermentation
and drying
123
6.
Roelofsen, P.A., 1958.
Fermentation,
drying, and storage of cocoa beans
.
Adv. Food Res. (8), 225
-
296.
7.
Sukha, D. A., 199
7,
The influence of
fermentation and drying on the flavour
and quality of selected cacao
(Theobroma cacao L.) genotypes
. M.Sc.
Research Project. Faculty of
Engineering, the University of the West
Indies, St. Augustine.
8.
Wood, G.A.R. and R.A. Lass, 2001.
Coc
oa
. 4
th
edition. MPG Books Ltd.,