Project Progress Report: " Investigation of rice kernel cracking and its control in the field and during post-harvest processes in the Mekong Delta of Vietnam - MS8 & MS9 " pot

Ministry of Agriculture & Rural Development

Project Progress Report

MS8 & MS9: THIRD & FOURTH SIX-MONTHLY REPORTS







July 2008



026/05VIE
Investigation of rice kernel cracking and its control in the field
and during post-harvest processes in the Mekong Delta of
Vietnam









NONG LAM UNIVERSITY

1
Table of Contents

1.
 Institute Information__________________________________________________ 2
2. Project Abstract ______________________________________________________ 3
3. Executive Summary___________________________________________________ 3
4. Introduction & Background ____________________________________________ 4
4.1 Project objectives ________________________________________________________ 4
4.2 Expected project outputs __________________________________________________ 4
4.3 Approach and Methodology _______________________________________________ 5
4.3.1 Implementation methodologies___________________________________________________ 6
5. Progress to Date _____________________________________________________ 11
5.1 Implementation Highlights _______________________________________________ 11
5.1.1 Influence of harvesting time on rice cracking_______________________________________ 11
5.1.2 Drying of paddy using flat bed dryer _____________________________________________ 12
5.1.3 Changes in physico-chemical properties of rice due to high temperature fluidised bed drying and
tempering _________________________________________________________________________ 14

5.1.4 Optimisation of high temperature fluidised bed drying performance by Response Surface Method
14

5.1.5 Changes in cracking behaviour and milling quality due to post-drying annealing and subsequent
storage 15

5.1.6 Sensory evaluation of cooked rice _______________________________________________ 15
5.2 Extension service________________________________________________________ 16
5.3 Smallholder Benefits_____________________________________________________ 16

5.4 Capacity Building _______________________________________________________ 16
5.5 Publicity_______________________________________________________________ 16
5.6 Project Management ____________________________________________________ 17
6. Report on Cross-Cutting Issues ________________________________________ 18
6.1 Environment ___________________________________________________________ 18
6.2 Gender and Social Issues _________________________________________________ 18
7. Implementation & Sustainability Issues _________________________________ 18
7.1 Issues and Constraints ___________________________________________________ 18
7.2 Options________________________________________________________________ 18
7.3 Sustainability___________________________________________________________ 18
8. Next Critical Steps ___________________________________________________ 19
9. Conclusion _________________________________________________________ 19
10. Statutory Declaration ___________________________Error! Bookmark not defined.
11. Project Progress Against Proposed Objectives, Outputs, Activities And Inputs
Error! Bookmark not defined.

12. APPENDICES ______________________________________________________ 20

2
1. Institute Information
Project Name
Investigation of rice kernel cracking and its control
in the field and during post-harvest processes in the
Mekong Delta of Vietnam
Vietnamese Institution
Nong Lam University HCMC
Vietnamese Project Team Leader
Dr Vinh Truong
Australian Organisation
The University of Queensland

Australian Personnel
Associate Professor Bhesh Bhandari
Professor Shu Fukai
Date commenced
April 2006
Completion date (original)
March 2009
Completion date (revised)
April 2009
Reporting period
12 months

Contact Officer(s)
In Australia: Team Leader
Name: Bhesh Bhandari

Telephone: +61733469192
Position: Associate Professor

Fax:+61733651177
Organisation: The University of Queensland
Email:

In Australia: Administrative contact
Name: Mr Kerry Johnston

Telephone: +61 7 3365 7493
Position: Research support officer

Fax: +61 7 33658383

Organisation: The University of Queensland
Email:

In Vietnam
Name: Vinh Truong
Telephone: 84-8-7242527
Position: Head, Department of Chemical Engineering
Fax: 84-8-8960713
Organisation: Nong Lam University
Email:



3
2. Project Abstract

3. Executive Summary
This report compiles the third and the fourth six-monthly reports and presents the
major activities from 1 May 2007 to 31 June 2008. During this period, systematic data
collection in the subsequent harvesting seasons was continued and updated for
harvesting time effect on rice cracking in the field. The experiments were undertaken
in wet season 2007 and dry season 2008 in Can Tho City and Kien Giang province. A
8-ton flat bed dryer installed in Tan Thoi 1 cooperative, Kien Giang province was used
for experiments in actual production condition. A combine-harvester was also
provided to Tan Phat A cooperative, Kien Giang province. A thresher was installed in
Tan Thoi 1 cooperative to complete the harvesting process from cutting by reaper to
threshing. Performance evaluations of drying methods in solar assisted dryer, flat bed
dryer, tower (columnar) dryer and fluidised bed dryer were carried out to improve
drying technique applied in MRD. Two 20 kg batch lab dryers were fabricated,
installed and used for drying experiments conducted in Nong Lam University.
Additional experiments were carried out to optimise fluidised bed drying and
tempering in multi-pass mode. Changes in physico-chemical properties of high
temperature fluidised bed dried rice were examined and cracking behaviour of rice
during post-drying annealing and subsequent storage was further investigated at The
University of Queensland. Sensory evaluation of cooked rice fluidised bed dried in
multi-pass mode has being undertaken at Nong Lam University. Training activities to
disseminate the information on harvesting and drying practices, and demonstrations of
dryers and combine harvesters were held for local extension officers and farmers
through training sessions in 10 districts in Can Tho and Kien Giang provinces from
June 2007 to June 2008. Study tours were also organised for small holder farmers in
Can Tho and Kien Giang provinces in December 2007. Two summation workshops of
this CARD project were arranged in Nong Lam University to make local authorities,
service providers, millers, extension workers and farmers’ representatives aware of
total grain losses and economical value due to grain cracking.

Reduced whole rice grain yield due to cracking is one of the major issues that directly
reduce income and availability of staple food to the farmers in the Mekong River Delta.
The cracking or partial fissuring of rice kernels may occur right in the paddy field due to
incorrect harvesting time/practice, improper post-harvest drying conditions and
inappropriate milling operations. This project aims to improve the quality and value of the
rice, through an integrated approach which encompasses farmers, millers, service
providers and extension workers and education institution. A key objective of this project
is to improve the knowledge of smallholder farmers by organizing workshops and
demonstration for farmer cooperatives in the region so that appropriate harvesting and
subsequent grain handling techniques are observed to improve rice grain quality.
Similarly there will be demonstration and workshops for small millers to encourage them
to install driers and/or provide them technical knowledge to practice optimum drying
conditions. Improvement of the capacity of the extension workers by providing updated
knowledge is another objective. The theory of grain drying will be advanced that would
improve designs of future dryers. The education institutions involved in the project will
work together for capacity building of their staff members in the Nong Lam University.

4
4. Introduction & Background
4.1 Project objectives
The specific objectives of this project are:

1. Identification and generation of information for the correct harvesting time on
cracking portion of various popular rice cultivars and seasons.
2. Improvement of the performance of current dryers applied in MRD to minimise
the level of rice cracking.
3. Optimisation of the drying method based on the fundamental structural relaxation
concept.
4. Investigation of changes in physico-chemical properties of rice due to high
temperature compact-drying system.

5. Investigation of changes in milling quality and physical strength due to post-
drying annealing and subsequent storage of rice.
6. Sensory evaluation of cooked rice processed from different multi-pass drying
methods.
7. Demonstrations to the farmers and provincial pilot cooperatives on the benefit of
mechanical drying against sun drying and economic value of the correct
harvesting time and method.
8. To make the farmers, service providers, millers and extension workers aware of
various factors responsible for harvesting and milling losses and degradation of
rice quality.

4.2 Expected project outputs
The expected outputs during the past 1 year period were:

• Field experiments are carried out to identify optimum harvesting time of different
rice cultivars to minimise grain cracking during dry and wet seasons.
• Best drying condition identification for current flat-bed and tower dryers in MRD.
• Experiments are conducted for optimum drying conditions identified for high
temperature compact driers.
• Experiments are carried out to investigate changes in pasting, gelatinisation
properties and degree of crystallinity of rice in relation to high temperature
fluidised bed drying and tempering.
• Molecular relaxation concept is continued to validate by 2 experiments
undertaken in Australia. Effect of drying and post-drying annealing at above and
below glass transition temperature of rice on the mechanical strength of rice, in
relation to level of kernel fissuring and milling quality is determined; Changes in
mechanical properties and milling quality of rice during storage are examined.
• Experiments are carried out to compare the sensory quality of cooked rice
processed from different multi-pass drying methods.
• Extension and training materials are produced.

• Training for 120 extension officers and 1685 farmers (2
nd
year).
• Study tour for 165 farmers and 20 extension workers (2
nd
year).
• Workshops for 130 service providers.
• Workshops to summarise the CARD project activities and progress.
• Production of Reports.


5
4.3 Approach and Methodology

The approach and methodology were adopted from the original project proposal. A 8-ton
flat bed dryer was installed in the Tan Thoi 1 cooperative, Can Tho City in September
2007 (Figure 1). Two identical 20 kg-per-batch lab dryers were fabricated and used for
drying experiments in Nong Lam University (Figure 2). This CARD project also
supported a combined-harvester to Tan Phat A cooperative, Kien Giang province. As per
the Objectives 1, 7 and 8, the smallholder farmers were the major target for training and
extension works through the pilot farmers’ cooperatives. Workshops were organised for
partners of this CARD project and extended participants to raise the importance of
correct harvesting and drying practices to reduce grain cracking. In association with
Objectives 2, 3, 4, and 5, glass-rubber transition and molecular relaxation concepts were
applied to evaluate the rice cracking behaviour at micro and molecular levels (Figure 3).
This approach was also used to explain changes in milling quality and physical strength
of rice during post-drying annealing and under storage. Existing fluidised bed dryer was
used to undertake optimisation study on high temperature rice drying.

Figure 1. A 8-ton flat bed dryer in Tan Thoi 1
cooperative, Can Tho.
Figure 2. A 20 kg-per-batch lab dryer in
Nong Lam University.


Figure 3. Pictorial representation of hypothetical state of the rice kernel undergoing drying,
tempering and cooling when glass-rubber transition concept applied to its state changes (more
explanation is attached in research report).
The MC line represents the changes in moisture content over time during the drying, tempering and cooling
stages.

MC
Glassy region
Rubbery region
Moisture gradients Moisture gradients
T
g
Moisture
readsorption
High drying
temperature

Temperature,
0
C
Drying time Tempering time
COOLING DRYING TEMPERING
Low drying

temperature

Time
Glassy state Rubbery state

6
4.3.1 Implementation methodologies

During 1 year period, there were eight main activities undertaken to achieve the goals as
highlighted in the objectives:

Objective 1 activities: Identification and generation of information for the correct
harvesting time on cracking portion of various popular rice cultivars and seasons.

Harvesting timeliness plays an important role in controlling rice cracking. The objective
of this experiment was to determine actual grain losses due to harvesting time of some
rice cultivars in Summer-Autumn and Spring crop seasons (2007-2008) in MRD. This
work complements the previous experimental works undertaken in 2006-2007.

Field experiments on correct harvesting time were carried out on some most cultivated
rice throughout wet (June to August 2007) and dry (March 2008) seasons (Figure 4).
Most cultivated rice varieties such as OM1490, IR50404, OM2718 of Tan Thoi 1 (Can
Tho) and OM2517, OM4498, IR50404, AG24 of Tan Phat A cooperative (Kien Giang)
were chosen as rice materials. Level of rice cracking for both brown and milled rice
samples and head rice yield were measured. The detailed methodology, results and
discussion of this experiment for 3 varieties carried out in March 2008 are presented in
the Appendix 1. The detailed results and discussion of this experiment for 7 varieties
carried out in 2 years will be presented in the next technical report MS10.

Objective 2 activities: Improvement of the performance of current dryers applied in MRD
to minimise the level of rice cracking.

This comprised of various activities as below:

Flat-bed drying
Experiments on performance evaluation of current dryers used in MRD were continued
to be conducted by Dr. Hien and co-workers. Previous experiments on a 8-ton flat bed
dryer in Kien Giang was summarised in the MS6 report. Another 8-ton flat bed dryer as
illustrated in Figure 1 was installed in Tan Thoi 1 cooperative (Can Tho City) in
September 2007. This dryer was fabricated by local service provider with a similar
design to the one made by NLU. However, the drying chamber was coupled with
“plenum center air duct” to distribute the drying air more uniform (Figure 5) alternatively
with “plenum side air duct“designed by NLU. Dr Hien and co-workers undertook
experiments on both 8-ton flat bed dryers to characterise the dryers in order to determine
the optimum drying conditions.

Experiments were also conducted with solar assisted 4-ton flat bed dryer in Go Gon
cooperative (Long An province) as mentioned in MS5 report. This dryer has been used
for drying experiments using coal, solar, and combination of coal and solar energies as
supplementary heat sources.

Tower drying
Tower drying in Long An Province was also used to evaluate its performances (drying
capacity, drying temperature, rice husk consumption, and electric power consumption),

7
drying technique (final moisture differential, grain crack and head rice recovery) and
economic aspect (labour requirement, investment and drying cost).
The available data will be incorporated into the training manuals. The full data and

analyses of both flat-bed drying and tower drying are attached to this report as Appendix
2.


Figure 4. Harvesting time experiment. Figure 5. Drying chamber with “plenum center air
duct” in 8-ton flat bed dryer installed in Tan Thoi 1
Cooperative, Can Tho province.

Objective 3 activities: Optimisation of the drying method based on the fundamental
structural relaxation concept.
Another experiment is being carried out by Dr. Truong and co-workers to optimise the
drying condition for multi-pass high temperature fluidised bed drying by using RSM
(Response Surface Method). This experiment adapted the drying conditions used
previously by Mrs. Tuyen (drying at 80
o
C for 2.5 min, then tempering for 40 min at grain
temperature) for Pass 1 to reduce moisture content of paddy to 18%-19%. Rice varieties
used are IR 50404 and Jasmine. Some preliminary results of this experiment are attached
in this report (Appendix 3). The full analysis will be submitted in the next technical
report.

Objective 4 activities: Effect of high temperature fluidised bed drying and tempering on
physico-chemical properties of Vietnamese rice variety
The first part of this experiment has been mentioned in the MS6 report in which the
effects of high temperature fluidised bed drying and tempering on level of rice cracking,
mechanical strength, head rice yield and color on two rice varieties (OM2717, A10) were
summarised. In the second part, the dried white rice in Vietnam was then imported to
Australia (University of Queensland) and analysed for pasting and gelatinisation
properties and crystallinity. Some SEM (Scanning Electronic Microscope) photographs
of rice structure were also undertaken at UQ. Only the A10 rice variety was used for

these measurements due to custom declaration difficulty. This second part was done by
AusAID supported UQ student Mrs. Tuyen. The brief analyse of the results can be seen
in the Appendix 4. The full analyse of the results can be seen in the next technical report.

Objective 5 activities: Investigation of changes in milling quality and physical strength
due to post-drying annealing and subsequent storage of rice.

This experiment was undertaken in The University of Queensland by Mrs. Tuyen. This
experiment investigated the effect of drying temperatures, tempering regimes and storage

8
conditions on the level of rice kernel fissuring, mechanical strength and head rice yield of
three Australian grown rice varieties, namely Kyeema (long-grain), Amaroo and Reiziq
(medium-grain). Paddy samples were dried at 40, 60, and 80
o
C and then tempered for 0,
40, 80 and 120 min. Dried rice samples were then stored up to four months at 4, 20 and
38
o
C. The investigation of post-drying annealing effect at above and below glass
transition temperature of rice on mechanical strength and its association with the level of
kernel fissuring and milling quality was expected to provide additional valuable insight to
understand the rice cracking behaviour. The details of this study are attached to this
report as Appendix 5 while full analysis can be seen in the next technical report.

Objective 6 activities: Sensory evaluation of cooked rice

Experiment on sensory evaluation of cooked rice was carried out to relate the effect of
fluidised bed drying to texture and sensory perception of rice. The optimum condition
was obtained from multi-pass drying of IR50404 and Jasmine rice varieties mentioned in

Objective 3. These rice samples (OM3536) were prepared from rice dried in multi-pass
mode by fluidised drying technique as described in Objective 3. Sensory attributes which
were assessed in this experiment include of flavour, firmness, stickiness, whiteness,
glossiness and overall tasting based on Vietnam Quality Standard upon cooked rice. The
details of this study can be seen in the next technical report.

Objective 7 activities: Demonstrations to the farmers and provincial pilot cooperatives
on the benefit of mechanical drying against sun drying and economic value of the correct
harvesting time and method.

As a key objective of this CARD project, the demonstrations and training activities for
the extension workers and the farmers were undertaken during wet season (July to
September 2007) in two districts of Kien Giang Province (Chau Thanh and Hon Dat) and
four districts of Can Tho City (Phong Dien, Co Do, Vinh Thanh, Thot Not). A total of
1025 farmer representatives participated in this one day training session (six days for six
districts). About 79 local extension officers also participated in the training session
(Table 1).

Table 1. Number of farmers and extension workers trained in different seasons.

Number of farmers
trained
Number of
officers/extension
workers
Province District Date
One day Total One day Total
1. Kien Giang
(Dry season)
Tan Hiep

Giong Rieng
25/02/2007
26/02/2007
124
189

313
10
15

25
1. Kien Giang

2. Can Tho
(Wet season)
Chau Thanh
Hon Dat

Phong Dien
Co Do
Thot Not
Vinh Thanh
28/7/2007
29/7/2007

22/9/2007
23/9/2007
29/9/2007
30/9/2007
181

178

195
139
165
167






1025
10
12

12
12
15
18






79
1. Kien Giang
(Dry season)
2. Can Tho

An Bien
Go Quao
O Mon
08/3/2008
09/3/2008
10/3/2008
183
159
135



10
11
10




9
Co Do 11/3/2008 183 660 10 41
Total:
Dry season 2007-2008: 1998 145

The similar training activities were also taken during dry season (March 2008) in two
districts of Kien Giang Province (An Bien and Go Quao) and two districts of Can Tho
City (O Mon and Co Do). A total of 660 farmers and 41 local extension officers
participated in this training session. Thus, from July/2007 to March/2008 a total of 1685
farmers and 120 extension officers were trained on cracking issues for controlling of rice
quality during harvest and post-harvest operations. These numbers are 1998 farmers and

141 extension officers for four seasons training program as shown in Table 1 (Feb 2007
to Mar 2008). The training instructors were Dr. Truong Vinh, Dr. Phan Hieu Hien, and
Mr. Tran Van Khanh. Participants visited the dryer in local sites and discussions were
held afterwards. These activities, training manual and extension material were submitted
in the MS7 report. The content of training session comprised of three lessons on
harvesting time, harvesting method and drying technique and demonstrations of the dryer
and the combined harvester (Figures 6-8). Every training session was finished up by
related discussions afterwards (Figure 9). Study tour was also made to 165 farmers and
service providers and 20 extensions workers in December 2007 (Can Tho and Kien
Giang, see Figures 10-13).



Figure 6. Harvesting lessons taught by Dr.
Truong Vinh in An Bien District, Kien
Giang.
Figure 7. Visiting the 8-ton-reversible air-flow flat
bed dryer (Tan Phat A cooperative) after training
lesson.



10

Figure 8. Demonstration of Nhut Thanh combine-
harvester.
Figure 9. Discussion after lessons in Can Tho.

Figure 10. Study tour on 15/12/07 (discussion). Figure 11. Study tour on 15/12/07 (dryer
demonstration).

Figure 12. Study tour on 16/12/07 (Hoang Thang
Combined-harvester Factory).
Figure 13. Study tour on 16/12/07 (Hoang
Thang Combined-harvester demonstration).



11
Objective 8 activities: To make the farmers, service providers, millers and extension
workers aware of various factors responsible for harvesting and milling losses and
degradation of rice quality.

Besides many training sessions for farmers and local extension workers, two workshops
on this CARD project year-end summation were also held in June 2007 and April 2008 in
Nong Lam University (Figures 14, 15). The purpose of these workshops was to
summarise the key activities of CARD project in every year to highlight the outcomes
and provide the overall picture of total losses due to rice cracking to local authorities,
service providers, millers, extension workers and representative farmers of cooperatives
involved in this project based on presentations and discussions. Intervention processes to
minimise grain cracking were also introduced and discussed. Representatives of media
agencies were also invited to attend these workshops to broadcast the emerged findings
of this CARD project. The hard copies of workshop materials were submitted previously.
CARD representatives were also present during the workshop held in April 2008


Figure 14. Summation workshop held in June
2007.
Figure 15. Summation workshop held in April 2008.

5. Progress to Date
5.1 Implementation Highlights

The brief highlights of the project executed in the past 1 year are described below.
5.1.1 Influence of harvesting time on rice cracking

It was found earlier that the level of rice cracking increased and head rice yield decreased
with delayed harvesting in wet season 2006 and dry season 2007. The same trend was
also observed in wet season 2007 and dry season 2008 in all rice varieties used in this
experiment.

Actual data collected in Tan Phat A cooperative, Kien Giang in dry season 2008
indicated that delayed harvesting increases the level of grain cracking substantially in all
three rice varieties OM2517, IR50404, AG24. Percentage of rice cracking went up when

12
rice was harvested later than expected harvesting day of farmers, particularly at +6 days
treatment. For each investigated rice variety, there is significant difference in head rice
yield (P<0.05) between treatments, assuming all samples were milled in the same
condition. Optimum harvesting timeliness in order to reduce grain losses due to rice
cracking is recorded as 86, 88, and 86 days for OM 2517, IR50404, and AG24,
respectively. Table 2 is a summary of optimum harvesting time for 7 varieties undertaken
by this project in rainy and dry seasons starting from June 2006 to March 2008. In
general, the optimum harvesting time of the rainy season is longer than that of the dry
season.

The results further confirmed that harvesting time has an influence on rice cracking.
Early harvesting results in lower percentage of rice cracking and higher head rice yield.
Though variations in rice cracking and head rice yield were observed between rice
varieties and crop seasons, the similar trend in all the cases demonstrated that correct

harvesting time is a key intervention opportunity to reduce grain losses.


Table 2. Optimal harvesting time for highest HRY (coloured numbers are the optimal growing time
for harvesting)

Variety Season
Time Growing time (day)
Rainy
June 06
88
90 92 94 96 98
OM1490
Dry
Feb 07
88 90
92 94 98 104
Rainy
June 06
88 90
92 94 96 98
OM2718
Dry
Feb 07
88 90
92
94 96 98
Rainy
July 07
86 88 90 92

94
96
Dry Feb 07
82 84
86
88 90 92
OM2517
Dry
Mar 08
82 84
86
88 90 92
Rainy
July 07
86 88 90 92
94
96
OM4498
Dry
Feb 07
87 89
91
93 95 97
Jasmine
Rainy
July 06
94 96
98
100 102 104
Rainy

July 06
86 88 90 92
94
96
AG 24
Dry
Mar 08
86
88 90 92 94 96
Rainy
June 07
88 90
92
94 96 98
IR50404
Dry
Mar 08
88
90 92 94 96 98


5.1.2 Drying of paddy using flat bed dryer

The sub-component 026/VIE-05 on the flat-bed dryer study, as specified in the second
year contract, consisted of the following activities:
#1. To install a 4-ton flat-bed dryer at Long An Province, using solar energy as
supplementary heat source, and conduct experiments with this dryer for 2 harvest
seasons.
#2. To continue to monitor the performance of the two types of the 8-ton flat-bed dryer at
Kien Giang Province (for the second season) and Can Tho City, with focus on

evaluating the effect of air reversal on the rice crack.

13
#3. To build two identical lab dryers at 20 kg-per-batch capacity for experiments under
laboratory conditions with identical paddy input in order to compare the air reversal
and non-reversal modes of drying on the rice crack.
#4. To test the performance of a number of tower (columnar) dryers this had been
installed in recent years in Long An Province.
#5. To continue with the Participatory Rapid Rural Appraisal (PRRA) survey on the use
of flat-bed dryer in the MRD.
#6. To report on the above results and to supplement last-year extension materials for
future training courses based on the updated data of the survey and experiments.
Activity #1 has been reported in MS6. Activities #4, 5, 6 covering the period from 1 July
2007 to 31 December 2007 are summarised and attached to this report. Activity #3 and
full analyses on all activities will be reported in the next technical report.


During last year, the sub-component on the flat-bed dryer had completed a number of
activities:
- Testing two types of 8-ton flat bed dryer at Kien Giang Province (for the second
season) and Can Tho City. Results of increase grain cracks were traced to the drying
temperature higher than recommended; this will be put into extension training
materials. The field test helped orienting the focus in the coming laboratory
experiments to consolidate the results.
- Testing the performance of one tower dryer which had been installed in Long An
Province. The grain crack was satisfactory in batches with a drying temperature
lower than 55
o
C and a drying rate of about 0.5 % /hr. On the economic side,
however, the drying cost three times higher than that of the flat-bed dryer is not

inducing to its adoption in the context of current labor and paddy prices. The
schematic diagram of tower dryer is shown in Figure 16.
3
2
III IV
II
1
I
11
7
6
5
4
8
9
10

Figure 16. Schematic diagram of tower dryer.
1: Feeding hopper. 2: Cleaner. 3: Feeding elevator. 4: Feeding elevator
5: Elevator. 6: Unloading wheel. 7: Fans 8: Rice husk furnace

14
9: Rice husk elevator 10: Rice husk hopper 11: Air chamber. 12. Drying towers

- More data from the continued PRRA survey on the use of flat-bed dryer in the
Mekong Delta were gathered. The trend for increased drying capacity, the role of
local manufacturers and local extension workers, the government support with
interest reduction for dryer loans, the drying during the dry-season harvest were
major findings.
- Training for thousand of participants as mentioned in section 4.3.1 (objective 7) on

the utilization of dryers were conducted; the lectures were updated with the Project
experimental data, and field visits at actual dryer sites.

As mentioned above, the full report will be attached in the next technical report.

5.1.3 Changes in physico-chemical properties of rice due to high temperature
fluidised bed drying and tempering

Studies undertaken in Nong Lam University on the effects of high temperature fluidized
bed drying and tempering on the physico-chemical qualities of two long-grain freshly
harvested Vietnamese rice varieties, A10 and OM2717, were reported in the MS6. The
analysis conducted in The University of Queensland on A10 rice samples showed that the
occurrence of partial gelatinization mainly on the grain surface during high temperature
drying and tempering altered some of the physicochemical properties and microstructure
of high temperature fluidized bed dried rice. As the rice becomes harder and stiffer due to
partial surface gelatinisation, it may require a longer cooking time when compared with
conventionally dried rice. However, the texture of the rice tempered for a prolonged time,
can be softer due to the alteration in the pasting properties. Further studies are needed to
evaluate the effect of high temperature drying on cooking quality.

The actual drying time involved with the use of flat bed driers ranges from 8-10 h for wet
paddy, if farmers want to reduce the grain moisture content to a safe level (14% wb). If
the paddy needs to be dried to 15-16% moisture, the fluidized bed drying system can be
used as a compact drier. The fluidized bed drying technique evaluated in this study is
strongly recommended for drying paddy in Vietnam during the wet season to maintain
rice quality as the use of this drying technique was shown to have an especially beneficial
effect on head rice yield. Full details of this study can be seen in the attached Appendix 4.
5.1.4 Optimisation of high temperature fluidised bed drying performance by
Response Surface Method

Preliminary works showed that high temperature fluidised bed drying and tempering can
be used to reduce high moisture content of IR50404 and Jasmine grains rapidly in multi-
pass. High moisture content paddy can be dried by two or three passes without adverse
effect upon milling quality. The detailed drying parameters are as below:

• For three passes:
Period 1: fluidised bed drying at 83-87
o
C for 2.5 min, then tempering at 73
o
C for 40 min;
Period 2: fluidised bed drying at 57
o
C for 4.9 min, and
Period 3: air ventilation at 35
o
C for 3-4.4h


15
• For two passes:
Period 1: fluidised bed drying at 80
o
C for 2.5 min, then tempering at 73
o
C for 40 min;
Period 2: thin layer drying at 35
o
C for 7-9h or at 40
o

C for 5.5h.

Further experiments to evaluate the drying cost in large scale operation should be carried
out. Preliminary results are introduced in this report as Appendix 3. The full analysis of
this experiment will be attached to the next technical report.

5.1.5 Changes in cracking behaviour and milling quality due to post-drying
annealing and subsequent storage

This study investigated the effect of drying temperatures, tempering regimes and storage
conditions on the level of rice kernel fissuring, mechanical strength and head rice yield of
three Australian grown rice varieties, namely Kyeema (long-grain), Amaroo and Reiziq
(medium-grain). It was found that tempering (at a constant moisture level) did not
improve the head rice yield even though the rice kernel stiffness increased and amount of
fissured kernels reduced with prolonged tempering duration 80-120 min. During the
storage period of up to four months at 4, 20 and 38
o
C, all measured parameters, such as
percentage of fissured kernels, hardness, stiffness, head rice yield, pasting properties
showed the similar increasing trends. A rapid change in these physical properties of all
rice samples were observed during the storage at 38
o
C. A significant increase in the
stiffness values of rice during storage suggested an existence of physical ageing during
storage of rice below its glass transition temperature.

The results in this study demonstrated another important role of annealing process which
also has an effect on cracking behaviour, mechanical strength and milling quality of rice
kernels. The relaxation of the molecular structure within rice starch results in the
densification of the internal structure of rice kernels that making the kernels then being

strong enough to withstand breakage during subsequent milling. This study also
enhanced the understanding of rice ageing during storage in relation to changes in rice
fissuring, mechanical properties and pasting properties. Rice kernels continued to fissure
during storage for 2 to 3 months, surprisingly without adversely affecting head rice yield.
The increase in head rice yield during storage, regardless of an increasing amount of
fissured kernels, implies that the physical integrity of the rice kernels was strong enough
to resist cracking during milling. Further research is needed at molecular level to confirm
the existence of physical ageing, by using X-ray diffraction or solid state NMR, which
were not covered in the scope of this study.

5.1.6 Sensory evaluation of cooked rice
This work is an attempt to compare sensory perception of cooked rice. The rice variety
was OM3536. Four rice samples subjected to this experiment were coded as Op1, Op2, C
and Control. Op1 was the optimum condition obtained from RSM experiment using
IR50404 rice variety as described in Appendix 3 item 5.1.4 (fluidised drying at 83
o
C for
2.5 min in the first pass and immediately tempering at 73
o
C for 40 min, then continued to
fluidised bed drying at 57
o
C for 4.9 min in the second pass and finally thin layer drying
for 4.4 h). Op2 was the optimum condition obtained from RSM experiment using
Jasmine rice variety (fluidised drying at 87
o
C for 2.5 min in the first pass and
immediately tempering at 73
o
C for 40 min, then continued to fluidised bed drying at 57

o
C
for 4.9 min in the second pass and finally thin layer drying for 3.24 h). C was rice sample

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fluidised bed drying at 80
o
C for 2.5 min then thin layer drying at 35
o
C. Control was rice
sample thin layer dried for 16 h at 35
o
C. The number of panellists was 12, sensory
attributes composed of flavour, firmness, stickiness, whiteness, glossiness and overall
tasting. The scale for each attribute is 5 points, the highest score can be obtained is 32.5
(impact factor of overall tasting is 1.5). The preliminary results showed that total scores
for A, B, C and control samples were 17.4, 23.5, 18.4 and 27.9 respectively. Due to other
experiment runs are being conducted, it is inconclusive of driving attributes made of
differences in sensory evaluation of cooked rice between four treatments. The full report
will be integrated to the next technical report.

5.2 Extension service
Extension activities including training session for 120 extension officers and 1685
farmers were organised in Can Tho City and Kien Giang Provinces. Ten training sessions
were held in ten districts from June 2007 to March 2008 with three parts: lessons about
drying and harvesting practices, demonstrations of dryer and combined-harvester, and
discussions after each demonstration. Total number of trainees are added up to 1998
farmers and 141 extension officers from February 2007 to September 2008 that is higher
than targeted number of farmers to be trained in this project (520 farmers/year and 39
extension officers/year). Study tours were organised for 165 farmers and 20 extensions

workers in December 2007 in Tan Phat A cooperative (Kien Giang Province) and Tan
Thoi 1 cooperative (Can Tho City). Results obtained from this project were incorporated
to extension and training materials that were distributed to trainees throughout these
training sessions. Summary of training activities, extension and training materials for the
period before 2007 were submitted previously in MS7 report.

5.3 Smallholder Benefits
The harvesters and driers are being installed in the cooperatives in which many of their
members are small holder farmers. These facilities are being managed and utilised by the
members of farmer’s cooperative. The most of the farmers are small and medium holders.
The training, workshops and visits also included small holder farmers along with other
participants.

5.4 Capacity Building
A large number of young and experienced staff members at NLU are continually
mobilised in research, extension, training activities. Many of them are visiting fields
during the harvesting period to collect data. Engagement of several staff members at
NLU in the project has helped to contribute to the capacity building of those staff
members. Also the project coordinator’s visit to rice research institutes in Thailand and
Philippines and one staff member’s to UQ (Australia) also contributed to capacity
building. Two more staff will be visiting UQ for further training during the next year.

NLU has specifically established a laboratory for CARD project. Besides meeting the
refurbishment cost, NLU has provided funds to equip this laboratory. All the pieces of
equipment purchased from CARD fund are located in this laboratory. This has
significantly contributed the capacity of NLU in research and rice testing ability.


5.5 Publicity

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Some baseline information and activities of this CARD project have been broadcasted in
two newspapers, i.e. Khoa hoc Pho Thong (Popular Science) on 9 May 2008 and
Vietnam News- The National English Language Daily on 29 April 2008 under name
‘Correct harvesting time to prevent rice cracking’ and ‘Post-harvest rice technologies top
talks’, respectively. Dr. Truong Vinh, project leader, also notified brief information of
experiments in this CARD project on Rural Economic Times (No. 20, May 2008)
mentioned that 70% of farmers of MRD late harvesting (see Figure 17). Besides, the
numerous training sessions organised during the past one year have sufficiently informed
the community leaders and members across Mekong River Delta directly or indirectly.
Scientific papers on harvesting practices, fluidised flat bed drying and rice annealing are
being prepared for publication in international journals.


Vietnam News: Post-harvest rice technologies top talks (April
08)
Rural Economic Times (May 08)

Popular Science Newspaper (May 9
th
, 2008)

Figure 17. Press cutting about activities of this project on Vietnam News, Rural Economic Times and
Popular Science Newspapers, respectively.

5.6 Project Management
The project has been managed by the team leader Dr Vinh Truong at NLU. Dr Truong
has received support from all higher authorities and sub-ordinate staff members at NLU.
There are 4 junior staff member (including one research student) who are helping the

project implementation. Support for the monitoring the project, project planning and
reporting has been received from Australian collaborators. The data collection,
compilation to proper format and translation into English has been delayed due to lack of
expertise of many staff members. This has been addressed and will be resolved.
Currently, Mrs Tuyen Truong has joined the research team after completing her MPhil at

18
UQ. Mrs Tuyen is assisting Dr Truong on the organisation and compiling and writing the
reports.

6. Report on Cross-Cutting Issues
6.1 Environment

The results obtained from experiments on 4-ton solar assisted dryer demonstrates that the
utilization of solar energy is not only be environmental-friendly (it can save 43-78% coal)
but also produces good grain quality, especially for Winter-Spring crop. The farmers in
MRD prefer to dry paddy by sun drying in Winter-Spring crop season for the direct
economic reason (low drying cost). Consequently, level of grain cracking in Winter-
Spring crop season is higher as compared to that of Summer-Autumn one. Comparing
three supplementary heat sources for 4-ton solar assisted dryer, Dr. Hien and co-workers
found that the drying temperature heated by solar energy was in range of 36-38
o
C but it
took long time to complete one drying batch. Combination of solar energy and coal was
handy to dry paddy just in a day and save 43-78% coal. Interestingly, head rice yields of
all treatments were equivalent to shade drying samples.

6.2 Gender and Social Issues

Nothing significant to report to date.

7. Implementation & Sustainability Issues
7.1 Issues and Constraints
The project has been attempted to implement as planned. The collection of information,
data analysis and delay in translation of information in English has made it difficult to
submit the report in time. We have only one milling lab for analysis of cracking,
chalkiness and HRY. However, the number of samples for analysis of all the experiments
and surveys were too many (1000 samples/season). Beside, the project awaits
information from number of collaborators. Therefore, the reporting has been continually
delayed. We are aware of this difficulty. We are hopeful that now the reports will be
submitted in planned due dates.


7.2 Options

No significant to report.

7.3 Sustainability
The project has received enough support from various individuals from the University,
provincial governments and farmer’s cooperatives. The project is quite sustainable in the
current environment. In our experience, cooperative model to implement the project has
been a great success. The reception and enthusiasm of the cooperatives have been very
encouraging.

19
8. Next Critical Steps
The project will be implemented as planned in the log-frame in the next 6 months. Work
in the next 6 months will involve training to farmers, service providers and extension
workers, and collection of more data. The more baseline data will be collected and
compiled with the existing data. The main projected activities are listed below:
#1. Transferring of the farmers training program to the provincial extension centres.

Supporting these centres for organisation of the farmer training.
#2. Organisation of the training program for extension officers in other provinces.
#3. Organisation of the training program on quality evaluation of milled rice for
millers, milling operators and related officers.
#4. Organisation of the training program on use and maintenance of the combined-
harvester for the service providers. The project will collaborate with the
manufacturers’ organisation.
#5. Continue to conduct experiments on flat-bed drying and multi-pass fluidised bed
drying to get more results on the optimum drying conditions.
#6. Staff training.
#7. Publication
#8. Workshop.

9. Conclusion
In our point of view, the project output is satisfactory. We have tried to meet the
milestones although there has been delay in submitting the reports due to some technical
reasons as described previously. There are certain outputs which are still not measurable
at this stage, but we have seen the significant impact of the project. We have achieved
number of outcomes which are important for the benefit of small holder’s farmers. We
have clearly found the difference in the field on the popularity of mechanical drying
operations and use of harvesters. This will be judged after the final impact survey of the
project.

20

10. APPENDICES

Appendix 1. Influence of harvesting time on rice cracking.

Appendix 2. Flat bed and tower drying.

Appendix 3. Optimisation of high temperature fluidised bed drying performance by
Response Surface Method.

Appendix 4. Changes in physico-chemical properties of rice due to high temperature
fluidised bed drying and tempering.

Appendix 5. Changes in cracking behaviour and milling quality due to post-drying
annealing and subsequent storage.

Appendix 6. Poster ‘Activities of CARD 026/VIE-05 of the year 2006’.

Appendix 7. Poster ‘Activities of CARD 026/VIE-05 of the year 2007’.

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