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

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 MR

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

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

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 

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

Completion date (original) March 2009

Completion date (revised) April 2009

Contact Officer(s)

In Australia: Team Leader

Position: Associate Professor Fax:+61733651177

Organisation: The University of Queensland Email:b.bhandari@uq.edu.au

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: k.johnston@research.uq.edu.au

In Vietnam

Position: Head, Department of Chemical Engineering Fax: 84-8-8960713

Organisation: Nong Lam University Email: tv@hcmuaf.edu.vn

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 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 drying annealing and subsequent storage of rice

post-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 (2nd

year)

• Study tour for 165 farmers and 20 extension workers (2nd

year)

• Workshops for 130 service providers

• Workshops to summarise the CARD project activities and progress

• Production of Reports

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

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),

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 80oC 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

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 80oC 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 oC 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

Co Do Thot Not Vinh Thanh

28/7/2007 29/7/2007 22/9/2007 23/9/2007 29/9/2007 30/9/2007

183

159

10

11

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