Program 4 Product And Process Development
Program Leader:
Dr Yunus Khatri
Ricegrowers' Co-operative Limited
Leeton
The rice processing sector is becoming increasingly focused on rice as a food. Quality at all stages of the production, processing and marketing phase is being increasingly seen as important in securing and maintaining markets. There are also new opportunities for rice as a value added product. This Program aims to enhance the processing sector by strategically targeting important critical areas and by encouraging cooperation with outside groups.
Sub-Program/Project Leader:
Mr Rod Bowman
Ricegrowers' Co-operative Limited
Leeton
Two sub-projects are currently being undertaken. These are:-
· Trash determination at point of receival (Mr Nathan Cutter and Ms Nicole McQuillan)
Trials to find a reliable or indicative measurement of trash content at the point of receival have been an ongoing pursuit since 1997. When excessive trash (including straw, chaff, flatheads etc.) is delivered, expensive and time-consuming delays at the intake pit, unloading and cleaning are created. Furthermore, storage capacity becomes limited.
Progress
· 1999-2000 Harvest
The Model S grain-cleaner was used at 18 receival site testing platforms during the harvest period. The instrument was used to measure the trash content of growers' paddy rice at the point of receival. The results of the test were provided to the grower, allowing for adjustments to the harvesting equipment to reduce the level of trash brought to the point of receival in subsequent loads.
Paddy samples that were tested and found to contain over 5% trash by weight were scrutinised more thoroughly to understand the make-up of the trash. The separated trash portion of the samples was sent to the Paddy Projects office. The trash samples were then slowly dried in an oven, de-hulled and hand picked to determine the contents of the trash.
The results of the Model S grain-cleaner trash analysis will be compared to the Leeton Quality Assurance Laboratory (QAC) trash analysis results. The QAC is expected to finalise the analysis of samples in November 2000.
· Optimisation of the Model S graincleaner
The Model S grain-cleaner has adjustable settings for the purpose of optimising the instrument for operation with specific grain. An extensive set of trials was conducted for the purpose of elucidating the optimal instrument settings for use in rice. The optimal feed rate, aspiration and sieve sizes were identified by testing 10 varieties of rice with known trash contents over a range of moisture contents.
· Brown rice moisture analysis at receival site
A high moisture range (11-28%) brown rice calibration has been developed for potential use at the point of receival during harvest. The measurement of moisture in brown rice will give advantages over the current method of testing moisture in paddy rice. Measuring moisture in paddy rice is problematic during periods of wet weather or heavy dews. The accurate detection of moisture with the Grainspec Near Infrared Transmission (NIT) instrument is hampered when there is an uneven distribution of moisture throughout the grain. However by removing the grain husk, the grain moisture can be measured in the brown rice. Tests have proven that measurement of moisture in brown rice with the Grainspec is more accurate than testing paddy rice compared to the standard air oven moisture test.
· Measurement of green grain in brown rice
Another advantage of de-hulling the paddy rice before it is analysed by the Grainspec NIT instrument is that the percentage of green grains in a sample can be determined at the same time that the moisture content is being measured. A test which can quickly evaluate the quantity of green grains in a sample of rice will be of value in the industry. Knowing the green grain content of brown rice will facilitate the segregation of rice (based on its green grain content) for use as seed stock and specific markets. A calibration for the measurement of green grains in brown rice has been developed for the Grainspec instruments. The green grain calibration works alongside the brown moisture calibration so a sample is only analysed once yet both variables are measured. At present only a rough indication of the weight percentage of green grain content is possible with the calibration. However with further work an accurate standard method of measuring green grain will be developed.
· Portable drying trials (Mr Darryl Hill)
Drying trials were conducted on a small batch dryer to simulate the rapid drying that occurs in RCL facilities over the harvest period. The batch dryer used was a Satake Batch Dryer (Model No. RMDR 12SD). A series of six trials were conducted, investigating dryer temperature, moisture removal, burner operation, moisture content effect on grain quality and the effect of time following drying on milling quality.
The four initial trials indicated that moisture removal rates were lower than those achieved in RCL drying facilities and a further two trials were conducted to examine significantly higher drying rates.
Conclusion
These trials highlighted the difficulties in maintaining the quality of paddy during rapid drying. As average moisture removal increased, whole grain yields were found to significantly decrease.
Operating burners continuously as opposed to intermittently indicated no advantage in either improved whole grain yields or fuel efficiency. Drying efficiency however could be improved by operating the burner at lower temperatures for high moisture paddy1.
Rapid drying of paddy below 18% caused significant reductions in whole grain yield. Therefore rapid drying using high moisture rice is recommended. Allowing samples a tempering time of two weeks after rapid drying provides some benefit in the form of improved whole grain yields.
It was concluded that the above findings should be applied to improve the operation of the Deniliquin dryer for the 2001 harvest and it is recommended that an automatic controller be installed.
Acknowledgements
|
Mr Chiaki Ono (Satake Australia) with the RMDR 12 SD portable dryer |
Sub-Program Leader:
Mr Scott Brindley
Ricegrowers' Co-operative Limited
Leeton
This project aims to develop systems to accurately monitor rice processing (milling). Markets are becoming increasingly aware of processing characteristics such as crack development, temperature gradients developed during milling and degree of milling.
· Development of software to capture quality and process data to measure and improve milling efficiency
The first stage of this work was to develop a software interface to allow Mill operators to enter data via keyboard into a PC. The software can then interactively display the data in the form of trends and Statistical Process Control (SPC) charts.
The second stage will add interfaces to specialised testing equipment to allow data to be collected automatically.
The third stage involves analysing data and creating control outputs to control the milling process directly.
This system is represented in the figure below.
This section of the work is now largely complete but new processes are still being added to the system.
· Develop automatic control of whiteners for degree of milling and/or whiteness
The aim of this sub-project is to develop an automated control system with appropriate sensing technology and actuator to deliver repeatable milling results and efficiency to the desired level of quality. This will deliver a tangible milling yield increase through the reduction of brokens. Application of Modern Control Theory and Soft Sensors will be researched.
This sub-project has been the main focus for the last two years. This work has been conducted with significant input from CICS Automation, a commercial spin off from Newcastle University.
The sub-project was broken into the following phases:-
Phase 1 Vertical Whitener Modelling
Stage 1.1 Investigating vertical whitener operation
Stage 1.2 Developing mathematical model of whitener process
Stage 1.3 Monitoring of product quality using settings calculated by model
Phase 2 Vertical Whitener Control
Stage 2.1 Development of dynamic model and control strategy
Stage 2.2 Implementation of control strategy
The modelling phase has been successfully completed. Stage 2.2, which involves implementation of the controller, has commenced. The block diagram of the process is depicted in the figure below.
The controller is depicted in the figure below.
The results so far on this project are looking very promising and it is expected that the fully automatic control of vertical whiteners will be completed at Leeton Mill soon.
· Moisture Meter Interface
Software Interface to Grainspec Moisture Meters has been developed so that sample data can be recorded automatically into the Operator Interface SPC system and collated with manually entered data. The process of taking the sample to the centrally located moisture meter is manual as there are a number of sample points.
· Packer Weigher Interface
Software Interface to Chronos & Richardson Packers, which are installed industry wide, was developed this year. This will provide online statistical information to the milling team for their packing operations.
· Process Weigher Interface
Software Interface to Process Weighers was developed and installed in Griffith Mill. These weighers will weigh paddy, head rice and large brokens throughput.
4.3 Quality assurance systems and post-harvest pest management
Sub-Program Leader:
Ms Robyn Delves
Ricegrowers' Co-operative Limited
Leeton
The Australian Rice Industry must continue to meet customers' quality expectations, both domestically and internationally. This Sub-Program focuses on:-
· Integrated Pest Management, and
· Food Safety
Physical control of rice - cold disinfestation of rice (4301)
Project Leader:
Ms Robyn Delves
Ricegrowers' Co-operative Limited, Leeton
Prof Michael Wootton
University of New South Wales, Sydney
· Impact of storage at -20ºC on rice properties
Losses resulting from insect infestations are widespread and involve more than loss of quality. Insect infestation also causes a reduction of nutrients in the grain. Controlling of insects with insecticides/pesticides rather than using preventive methods incurs great cost. In addition, infestations result in dissatisfied customers and related market problems that develop a poor reputation in marketing channels.
Rice markets are becoming increasingly discerning so there is a need to develop alternative means to avoid use of post-harvest chemicals. The most prevalent means for disinfesting insects from stored grain relies on chemical fumigants such as phosphine and methyl bromide. However, the range of fumigants currently in use is decreasing as these are removed from permitted lists due to health considerations. In addition, there is increasing consumer resistance to the use of pesticides in general due to perceived problems related to health and wellbeing.
One alternative to pesticides for disinfestation of stored grain is the use of inert dusts. However, there are problems with these, including their overall effectiveness, effects on flow properties and bulk density of grain, and subsequent removal of the inert dust for sale and further processing of the grain. This is likely to be a particular problem for white rice. The use of low temperature storage avoids the problem of the use of pesticides and consequently the grain would be free of chemical residues. This would enable disinfested rice to be produced, which could be fairly and accurately described as residue free or any similar terms for domestic and export marketing.
No previous study has been done to examine the effect of low temperature on rice properties.
The present study was planned to avoid use of chemicals during storage and assessing the effect of low temperature storage on quality characteristics of rice. Keeping in view the aims; the experiment was set in Leeton and the samples were analysed for various quality aspects at the University of NSW.
Progress
Rice was stored at -20ºC as paddy, brown and white forms in one tonne bulker bags and, in the case of white rice, in 1kg retail packs. Temperature in the rice was monitored continuously during the five weeks of frozen storage and samples were taken after five weeks for quality evaluation. Quality parameters evaluated included milling yield, cooking behaviour and RVA pasting properties. Also measured were in vitro starch digestibility and crystallinity by X-ray diffraction. These results were compared with those from control samples stored under ambient conditions. It was found that storage at -20ºC had very little impact on most of the rice properties examined.
Conclusions
Low temperature storage at -20ºC does not affect most of the rice properties such as milling yields, quality parameters, bulk density, water absorption, cooking time, pH and soluble solids significantly. It is evident from the study that low temperature technique is very useful and gives us further indication that control of insects can be tried by exposing them at low temperature without affecting quality of grains.
This technique will avoid the problems associated with pesticides and consequently grain will be free of chemical residues. It will enable disinfested rice to be produced which could fairly and accurately be described as residue free or any similar term for both domestic and export marketing.
Chemical alternatives - Ethyl Formate and Carbonyl Sulphide (4303)
Project Leader:
Ms Robyn Delves
Ricegrowers' Co-operative Limited
Leeton
Due to the phase-out of methyl bromide for all but pre-shipment and quarantine use it has been necessary to develop alternative fumigants for the disinfestation of durable food commodities. Carbonyl sulphide (COS) and ethyl formate are two alternatives under development at the Stored Grain Research Laboratory (SGRL) at CSIRO Entomology. Both these materials have been through a research path aimed at defining the condition for their use and their efficacy against some insect pests of stored products.
Neither carbonyl sulphide nor ethyl formate have been systematically tested on rice and rice products. The research undertaken is the first stage of assessing the applicability of the alternative fumigants to these products, hopefully opening a pathway for effective fumigation using a material other than methyl bromide.
The work undertaken was designed to investigate the following three major areas:-
1. sorption of COS and ethyl formate on the commodity;
2. airing-off of fumigant - rate and completeness; and
3. detrimental effects on product quality.
Research on areas 1 and 2 is being carried out at SGRL, with area 3 being addressed by Ricegrowers' Co-operative Limited on material exposed at SGRL during the sorption/desorption studies. Areas 1 and 2 are very important criteria in determining the logistic and economic feasibility of the treatments. Area 3 is the critical step in determining whether it is sensible for the research to proceed.
Conclusions
· Milled white and brown rice
The results obtained from SGRL laboratory exposures of rice products indicate that there are unlikely to be any problems obtaining conditions that will control insects in milled rice (white or brown) at 25ºC with either ethyl formate or carbonyl sulphide. In this domain (ie milled product 25ºC), and on the basis of results obtained, operational requirements, in terms of application and ventilation, should be similar to those developed for cereal grains.
The interpretation of the 10ºC results is more equivocal as it is outside the domain of most previous insect toxicology studies. On the observed results it is likely that carbonyl sulphide will be effective on milled rice (brown and white) at this temperature but studies elsewhere have shown that a longer exposure period than those tested may be necessary. There are very few studies on the toxicity of ethyl formate at low temperatures, those that exist suggest its toxicity is not greatly affected but very considerable work is needed before a definitive answer can be given for all species likely to be encountered.
A next step in proving the fumigants and progressing towards a future registration would be small-scale field application on milled product under ambient conditions, assuming problems are not revealed during quality assessment.
· Paddy and rice flour
Paddy and rice flour were more sorptive of both fumigants than expected. This means that the concentrations reached after application were lower than expected and the level of insect control would be much more doubtful. Higher dose rates are likely to remedy this but are more likely to have an adverse impact on quality. Further exposures and quality testing would be needed to ensure this does not occur before field trials could be attempted.
4.5 New rice-based foods (4501)
Sub-Program Leader:
Mr Phillip Williams
Ricegrowers' Co-operative Limited
Leeton
The Australian Rice Industry always seeks to add value to its products prior to sale. To date, however, there has been limited additional value adding. New products could enhance returns to the industry through increased processing. This project has examined a number of potential processes.
Progress
During the year ending July 2000, final development work was completed on the first of the quick cooking rice products. Research on these products has been completed and commercial production of a range of quick cooking rice products has commenced. These products began to appear in the market place around April 2000.
New product development work is now focused on further types of quick cooking rice products to shorten the "cooking" time even further while retaining a suitable rehydrated product.
Development work has also been completed on new types of rice cakes and these have also now reached commercial production.
Development work has also commenced on a range of rice flour-based new products. Work has so far been to determine the suitability of current Australian rice varieties for some of these new rice-based products. Work undertaken in collaboration with Food Science Australia on production of extruded snack products from rice aged under a range of storage conditions is due for completion in August. To date the preliminary results indicate significant differences in the various rice flours.
Development of new vitamin and mineral fortification technique for rice (4502)
Project Leader:
Mr Phillip Williams
Ricegrowers' Co-operative Limited
Leeton
This project aimed to establish a simple means of applying folic acid to rice to produce a new enriched rice containing between 1.54 - 3.08mg/kg of folic acid. Folic acid (folate) is a vitamin essential to humans and is now added to a range of food products. However folic acid is a bright yellow coloured vitamin and enriched rice using the process currently used to add thiamin and niacin produced bright yellow coloured grains of rice in the finished blend. This was unacceptable to potential purchasers who may have mistaken the enriched rice for `stack burnt' or damaged rice.
Progress
Experimental work on this project has been completed. Samples of folate enriched rice have been produced and are currently undergoing storage to assess the stability of the added folic acid over time. Progress results to date are encouraging, as acceptable levels of folic acid activity have been found at six months of storage.
This process has been trialed at pilot scale level and rice produced using this process has received satisfactory consumer acceptance and has met the required minimum and maximum levels for folic acid. It is anticipated that the outcome of this project will be the installation of a commercial plant to produce folate-enriched rice.
Investigating the physical inter-relationship between rice flour and the protein actomyosin (4503)
Project Leader:
Mr Phillip Williams
Ricegrowers' Co-operative Limited
Leeton
This project aims to investigate the suitability of Australian rice flours for use as a value added ingredient in smallgoods and other manufactured products.
Progress
Work on this project has recommenced with the appointment of a replacement food technologist earlier this year. Work is presently proceeding towards establishing the functional properties important for these applications. Suitable methods to assess these properties are being developed. Experimental work to date is investigating the oil and water absorption properties for rice flours from the various rice varieties and also using rice flour with various particle sizes. Data collected to date has found substantial differences between some varieties. Particle size is also a variable and work to determine the optimal particle sizes is continuing.
Starch-lipid interactions and their role in ageing processes in rice (4504)
Project Leader:
Prof Kevin Robards
Charles Sturt University
Wagga Wagga
The project aims to:-
Progress
A PhD student, Mr Zhongkai Zhou, has been appointed to this project which commenced in January 2000. He has prepared a comprehensive review of the literature. Samples were collected in May and these are being stored for time-trials.
Analytical methods have been developed and validated for phenolic acids, amylose/amylopectin, differential scanning calorimetry, total lipid and fatty acid profiles. Since May these tests have been applied to samples and results will be presented at the Cereal Chemistry Conference in September this year.
Milestones
Milestone |
Year 1 |
Year 2 |
Year 3 1999/2000 |
Year 4 |
Year 5 |
Year 6 |
Year 7 | |
4.1 |
Grain quality in the pre-milling phase |
|||||||
Appointment of scientific officer |
X Consultants used |
|||||||
Sampling procedures optimised. |
X Commenced |
X 4 |
||||||
Individual grain moisture distributions monitored |
X Commenced |
X 4 |
X 4 |
|||||
Optimum grain drying strategies developed |
X Commenced |
X 4 |
X |
X |
||||
Training programs developed |
X Deferred |
X 4 |
X |
|||||
Training programs implemented |
X 4 |
X |
X |
X |
X | |||
4.2 |
Development of rice handling in-line process control |
|||||||
Software development |
X Commenced |
X 4 |
||||||
Closed loop control developed for degree of milling/whitening |
X Commenced |
X 4 |
||||||
Moisture meter interface developed |
X 4 |
X 4 |
||||||
Packer weigher interface developed |
X 4 |
X 4 |
||||||
Process weigher interface developed |
X 4 |
X 4 |
||||||
Closed loop system for broken grain content developed |
X 4 |
X |
X |
|||||
Closed loop system to maximise hulling efficiency developed |
X |
X |
X | |||||
System implementation |
X |
X |
X | |||||
4.3 |
Quality assurance systems and post-harvest pest management |
|||||||
IPM strategies evaluated |
||||||||
- Ethyl formate |
X |
X Commenced |
||||||
- CO2 fumigation |
X |
|||||||
- Cool temperature treatment |
X |
X Commenced |
X Continuing |
|||||
- Phosphine fumigation |
X Implementation |
X |
||||||
- Carbonyl sulphide |
X 4 |
X |
X |
|||||
- Designing out pests |
X |
X Deferred |
X 4 |
|||||
HACCP systems |
||||||||
- rice-based foods plant |
X Commenced |
X 4 |
||||||
- mills and stock food plants |
4 (flour mill) |
X Commenced |
X RCL |
|||||
- rice receival sheds and on-farm |
X |
X |
X |
X | ||||
4.4 |
Rice hull use |
|||||||
Potential for energy conversion determined |
X 4No potential |
X n/a |
X n/a |
|||||
Potential for hull-based alternatives determined |
Commenced |
X Continuing |
X Continuing |
X |
||||
Other uses for hulls investigated |
X |
X |
X |
X | ||||
4.5 |
New rice-based foods |
|||||||
Quick cook rices developed |
X Commenced |
X 4 |
X _ |
X |
X |
|||
Feasibility for pouch packed cooked and frozen rice |
X Commenced |
X 4 Feasibility study completed however RCL has deferred decision on commercial viability |
||||||
Frozen rice products developed and test marketed |
X Not feasible |
X |
X |
X |
||||
Development of pouch packed products |
X Commenced |
X 4 |
X |
X |
||||
Evaluation of waxy rice flour |
X Commenced |
X No application |
X other flours investigated |
X |
||||
Potential to produce and market rice noodles evaluated |
Evaluated and discontinued |
Re-evaluated |
4 |
|||||
Other rice-based products evaluated |
4 |
X |
X |
X |
X |
X = To be completed (in some cases this exercise is spread over several years).
4 = Achieved (if not achieved, status provided)
1 High moisture rice is defined as paddy with receival moisture contents of above 18%.
