BioMatNet Item: FAIR-CT95-1105 - Cascade Refining of European Wheats for Production of High Quality Products for the Paper Industry

FAIR-CT95-1105
Cascade Refining of European Wheats for Production of High Quality Products for the Paper Industry

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FAIR Area 2.1 - Chemical and Physical Processes : Paper/Pulp : Process Engineering : Starch

	Proposal No:	FAIR-CT95-1105
	Date Prepared:	October 2000, December 1999, December 1998, April 1998
	Source:	Final Report Third Annual Progress Report Second Annual Progress Report First Annual Progress Report

Final Report October 2000

Third Annual Progress Report December 1999

Second Annual Progress Report December 1998

Abstract

Background The Cascade project is a non-food research project dedicated to the production of chemically-modified starch-rich wheat flour for the paper industry. It is characterised by a close collaboration between the seed grading/milling industry, the wheat flour modification industry, the paper industry and associated research institutions. The group of partners in the Cascade project represents a complete production line from the raw wheat material to the end product and its applications in the paper industry. The group includes research institutions capable of developing on-line quality control of the intermediate and final products as well as setting up economical feasibility models for the production.

In this project the paper production is based on chemically-modified starch-rich European wheat flour and covers the grading and inactivation of whole seed wheat, through fractionation and milling to the chemical modification of wheat flour and use of the modified wheat flour in applications for the paper industry.

Objectives The overall objectives of the Cascade project are:

to scale up a vertically-integrated chain for production of cheap and high-quality modified starch wheat flours for the paper industry
to develop a closed-cycle production system for modified starch wheat flours
to ensure that all production steps are "environmentally friendly"
to ensure full utilisation of the raw material
to ensure a positive socio-economic impact

Activities The work has proceeded according to the project plan that specifies continuing wheat-sample collection and analysis for each harvest. The first year was dedicated to the collection and analysis of a wide range of wheat samples to establish the range of wheat characteristics and their suitability for chemical modification. In the second year of research the focus was on the collection, sorting, milling and chemical modification of selected wheat samples.

Results Density sorting of wheat to produce high and low protein material has been tested on a few samples. The economic analysis shows that the Cascade products are almost competitive with traditional starch products. Some reductions of the costs are necessary.

Future activities The testing of samples from the harvest of 1998 will continue to verify results achieved earlier in the project. In the near future a full-scale trial in a commercial paper mill will be carried out using selected Cascade product. The trial should prove the performance of the modified wheat and pin-point advantages and problems.

Summary

Introduction The Cascade project is concerned with the production of chemically-modified starch-rich wheat flour for the paper industry. It is characterised by a close collaboration between the seed grading/milling industry, the wheat flour modification industry, the paper industry and associated research institutions. The group of partners in the Cascade project represents a complete production line from the raw material to the end-products for application in the paper industry.

In this project the production of chemically-modified starch-rich European wheat flour covers the grading and inactivation of whole seed wheat, through fractionation and milling to chemical modification and use of the modified wheat flour in the paper industry, thus forming an entire production chain from wheat to paper.

Activities

The general tasks and current achievements are as follows:

Task 1 Wheat grain of different quality will be grown or bought from various European suppliers for processing and testing. The wheat will be graded into high- and low-protein seeds. Grading trails for high/low protein fractions with wheat from Denmark and Austria have been carried out during the first two years, giving indications concerning the prospects of obtaining such fractions.

Task 2 The low-protein seeds will be fractionated during subsequent milling and sifting techniques to obtain low-protein high-starch flours of acceptable quality. A number of samples have been processed through the fractionation and milling steps. In particular, the European wheat varieties Terra, Brigadier and Hussar have been milled and sent for modification.

Task 3 The low-protein high-starch flours (and alternatively the low-protein seeds) will be inactivated with regard to micro-organisms and enzymes. It was found impossible to obtain appropriate infected samples during the first two years because the harvests of 1996 and 1997; it requires damp weather during the harvest to get infected samples. It was possible to get this material from the harvest of 1998. Trials are planned within the next two months.

Task 4 The aim of this work is to find the options and limitations of the dry chemical modification, anionic and cationic etherification, of special wheat flours obtained from Cascade refining (tasks 1 - 3) with quality focused on the needs of wet-end additives in the paper industry. It is the aim to compare these results with the properties of the modifications produced using conventional wet technologies. Test equipment has been installed and is being used with Cascade samples. The work is proceeding as expected and good results have been obtained.

Task 5 From raw material to final product, an AT-LINE (IN-LINE) quality control system will be developed (and tested) based upon spectroscopy screening and multivariate data analysis. A large number of raw and modified Cascade samples have been analysed using traditional chemical analysis and using Near Infrared Spectroscopy. The basis for mathematical product control models has been established with a number of fast screening models developed as substitution for traditional chemical measurement.

Task 6 The modified low-protein high-starch flours will be tested in the paper production process and the quality and quantity price ratio evaluated by the paper industry and by the marketing study group. Selected Cascade products have been tested for paper-making at the Stora Corporate Research laboratories with promising results. In addition the market potential has been analysed.

The activities under items 7 and 8 run in parallel with production chain steps 2 - 6. Quality control covers the intermediate products all through the production chain. The environmental and economic activities also cover the whole production chain. The selection of raw material is guided by the results obtained in thorough investigations of the isolated/integrated effects of specific raw materials processed through the chain (steps 2-6). The selection of raw material (wheat) occurs prior to the grading step. Hence it is not strictly a part of the Cascade project, but a controlled selection of raw material is necessary to achieve the objectives.

Results

Task 1 The results of the tests revealed valuable information about the quality of the density-graded wheat fractions with particular characteristics. The results indicate a need for further modification of the density table, as there seem to be irregularities in the most dense fraction. The aim is to develop techniques that can sort the wheat in a high-protein fraction and a low-protein fraction. So far Austrian and Danish wheat samples have been tested.

Task 2 The first two years have been spent on the testing of equipment and the analysis of products. A number of samples from different wheat varieties have been milled and processed through the chemical-modification step for performance testing. In particular, a number of wheat flour samples with a wide range of ash, protein, fibre, fat, starch and granulation (a milling dependent parameter) have been modified to provide a picture of the specific effects of these parameters in the modification process.

Task 3 The testing equipment has been installed and samples have been used to adjust the equipment for the best performance. Unfortunately, it has been impossible to find infected samples because the harvests of 1996 and 1997 were dry. The harvest of 1998 was more wet, and samples have been found and will be inactivated during the autumn of 1998.

Task 4A large set of production line-samples (modified wheat flour) and the corresponding raw wheat flours have been analysed to obtain criteria for successful modification. The wheat variety Brigadier performs well in the modification process for anionic modification. Based on the analysis results of the laboratory trials and the production-line samples a large-scale test will be carried through within the next year at one of the Stora Corporate paper mills.

Task 5 Preliminary results are very promising regarding the development of fast screening methods for measuring the content of protein, ash, starch, fat and fibre in the wheat flour. Near Infrared analysis can predict the charge of the modified wheat flours with a very high correlation. This is quite interesting for the ongoing development of fast screening methods for controlling the modification process. The rheological behaviour of wheat flour gel has been studied. It was shown that a higher degree of modification has a lesser effect on the rheological behaviour of the modified wheat flours.

Task 6 The total production cost for each step in the production chain has been calculated in order to identify critical economic parameters, one of which has been shown to be the amount of chemicals used in the modification step. A reduction in chemical use can reduce the cost of the Cascade products substantially. Selected Cascade products have been tested with respect to a number of quality-characterising parameters in the Stora laboratories with positive results. The Cascade products seem to perform as well as other wheat starch products. Within the next year further laboratory tests are planned. The results of these tests will guide a large-scale trial of chemically-modified wheat flour.

Discussion

The first two years of the Cascade project have been used to get as complete an overview of the possibilities and limitations under each task as possible. The last two years will be used to verify results from the first period and to extend the investigation of critical aspects of the Cascade concept.

The partners have endeavoured to cover as wide a range as possible of raw-wheat, wheat-flour and modified wheat -flour samples. Samples with extreme characteristics have been collected and analysed. Based on the work and the results from the first two years the following conclusions can be reached.

In general, the project proceeds according to plan. Only minor deviations from the plan have been encountered and they will be accounted for by intensification of the work in the last two years.
All equipment has been successfully installed and tested.
Options for most equipment have been defined but will be updated as required as new results become available over the next two years.
The majority of the planned batch trials have been carried through.
The Cascade products perform as well as traditionally produced wheat starch.
It is possible by Near Infrared Spectroscopy to fast-screen modified wheat flour for electrical charge and degree of substitution with a high accuracy.
It is possible by Near Infrared Spectroscopy to fast-screen wheat for protein with a high degree of accuracy.

Future Actions

The project will continue according to the tasks, sub-tasks and milestones. The research will be intensified for the sub-tasks behind schedule, and for the sub-tasks ahead of schedule the work will continue within the frame of the project. Specifically, the actions listed below will be carried through the next two years.

Further laboratory-scale testing is planned within the next six months to prepare for large-scale trials.
Industrial-scale (30 - 40 tons of modified wheat flour) paper-making trials will be carried through at Stora Paper Production in Sweden, the results to be analysed thoroughly and distributed backwards through the chain.
New batch trials for the different steps in the Cascade production will be carried through.
New samples from the harvest of 1998 are being collected to span the variation space further.
The fast screening methods will be further refined and the results verified.

First Annual Progress Report

Introduction
The overall Cascade project is presented here and the progress if the individual participants commented on. The Cascade project is a non-food research project dedicated to the production of chemically modified starch-rich wheat flour for the paper industry. It is characterised by a close collaboration between the seed grading/milling industry, the wheat flour modification industry, the paper industry and associated research institutions. The group of partners in the Cascade project represents a complete production line from the raw wheat material to the end-product and its applications in the paper industry. The group includes research institutions capable of developing on-line quality control of the intermediate- and final products as well as setting up economical feasibility models for the production. In this project the paper production is based on chemically modified starch-rich European wheat flour and covers the grading and inactivation of whole seed wheat, through fractionation and milling to the chemical modification of wheat flour. Using the modified wheat flour the Cascade project extends to applications in the paper industry forming an entire production chain from wheat to paper.

Traditionally, the production of starch derivatives is based on refined starch which is almost pure, but requires a series of wet-processes, which are energy and water consuming with a large discharge of waste water. In contrast the chemical wheat flour modification process in the Cascade project is based on a relatively new technique where it is chemically modified entirely in "dry-state". The discharge of pollutants from both the wet starch manufacturing process and the chemical modification is eliminated and therefore the total energy and water consumption in the paper production is reduced significantly as compared to conventional production of chemically modified wheat starch. However, there is a trade-off in "dry-state" production, because the chemically modified wheat flour is less purified than conventional starch products. The modified wheat flour contains 2 - 10% protein as compared to only 0,2 - 0,5% in conventionally refined starch products. However, for many paper applications the less purified modified wheat flour will be sufficiently pure.

Objectives
The objectives of the Cascade project are:

to scale up a vertically integrated chain for production of cheap and high quality modified starch wheat flours for the paper industry
to develop a closed cycle production system for modified starch wheat flours
to ensure that all production steps are "environmentally friendly"
to ensure full utilisation of the raw material
to ensure a positive socio-economic impact on the society

Methodology
The production line of the Cascade project consists of a number of production steps forming the chain. The first step is selection of raw material (wheat). This step is not strictly a part of the Cascade project, but a controlled selection of raw material is necessary as the first step of the overall the production chain that includes selection, grading, inactivation, dry fractionation and milling, dry modification, paper making and quality control, to which are added work on the environmental and economic aspects as well as market analysis for paper. Both quality control and the environment and economic activities also cover the whole production chain

The aim is to optimise every production step with respect to requirements incurred by subsequent production steps in order to reach maximum scientific results and industrial potential. Selected varieties of European wheat are processed forward through the production chain under intense surveillance. The experience obtained is distributed backward through the chain in order to optimise starting production based on the customers needs. In the start phase of the Cascade project small samples (laboratory scale) have been processed through a few production steps to establish initial knowledge about chemical and physical parameters and requirements (pros and cons) in relation to the production steps. Later in the project larger samples (industrial scale) will be selected and processed through the whole production chain and the results evaluated.

Visits were made to Ceresan GmbH to study chemical modification technology and the production process and to Stora Corporate Research in Sweden to become more acquainted with the paper making technology and to discuss the use of chemically modified wheat flour, the problems it could pose and possible solutions. The discussion led to a definition of further investigations such as how the particle size of the wheat flour effects chemical modification. Also, Cimbria Heid GmbH. in Vienna was visited in order to obtain an impression of the performance of the grading equipment with respect to wheat grading. Three samples of wheat were selected with respect to the protein content and kernel size, since these parameters influence on the starch content. Using these samples the grading equipment was tested and the sorted output analysed by spectroscopic methods. A visit was also paid to the Bioraf Denmark full scale pilot fractionation and milling plant.

Test equipment
For some of the partners the first phase of the project involved installation of testing equipment, including electronic analysis equipment, to be used for a particular set of single wheat kernel analysis for the Quality Control tasks. Cimbria Heid installed a density grading table having a peak capacity of approximately 4000 kg/hour. Cimbria Unigrain has installed a toaster used for inactivation of micro-organisms in the wheat by rapid heating by hot air. The temperature is raised to 300-600 degrees for a very short period of time. This kills all living micro-organisms both on the outside and under the shells of the wheat seeds. The first trials should reveal information about the influence of the micro-organisms in the chemical modification of the wheat flour. At Bioraf an existing fractionation and milling line has been modified in order to perform the specified tasks. The fractionation line and the milling line were those installed previously under an ECLAIR project in close cooperation with United Milling Systems. Other equipment acquired includes a Near Infrared Transmission analyser for single kernel and bulk analysis, a Near Infrared Reflectance analyser for investigations on wheat flour and the modified wheat flour and a Perten Single Kernel analyser to test the hardness and density of the wheat kernels.

Results
Based on the first milling and modification results wheat samples varying with respect to variety, soil growing condition, ash, protein, starch, and fibres have been selected from the harvest of 1996 and 1997. Two wheat varieties were selected for the density grading tests - one variety with a high starch content and one with a normal/low starch content. At this stage it is uncertain whether micro-biological activity and enzymes have an influence on the chemical dry modification process and the quality of the chemically modified wheat flour. Trials have been planned to clarify this. However, the low rainfall during harvest in 1996 and 1997 has made it difficult so far to find damaged wheat samples with micro-biological activity.

A number of wheat samples of different varieties have been selected for milling trials. The results are not yet available, but the samples have been modified chemically and will be analysed in the near future. From the previous trials it has been shown that the "low protein" Dutch variety Ritmo obtains positive characteristics when milled in a conventional wheat flour mill plant.

In the chemical dry modification process the main problem from the start of the Cascade project was that "end-effects" are known (to a certain extent), but "relationships and dependencies" are unknown. In order to establish a knowledge database of the chemical parameters and the process parameters 120 samples of raw material from the intake of the production line and 120 corresponding samples from the output of the modification process have been taken and are being analysed. A set of optimal processing parameters has been defined for the chemical modification process. Fixing these parameters will make the results of sample modifications directly comparable. Various varieties of wheat flour with different granulation have been milled and chemically modified. The samples will test the effects of varying granulation and the chemical composition. These are being processed.

The modified wheat flour has been used as the starch component in paper coating and as the binding component between layers of fibres. Paper made using this starch flour have been analysed technically (physical parameters) and analytically (chemically and optically) in order to guide former production steps towards an optimum with respect to the end-product. As reference a modified potato starch product was selected to be tested against the modified wheat flours and as a second reference an industrially modified wheat starch available on the market. So far a problem of using modified wheat flour seems to be the fine material retention, since it shows a lower performance than the reference potato starch.

Both NIT and NIR spectroscopy have been used to estimate quality parameters of raw wheat flour and modified wheat flour. Results show that quality can be predicted by NIT/NIR fast screening. The method will be further developed. NIT/NIR spectroscopy has also shown encouraging result for fast screening of the modification degree (chemical substitution) s. It has been possible to predict (fast screen) the degree of modification with a correlation of 0.99.

When the modified wheat flours enter the jet-cooker just before being applied in paper making the rheological properties describe the behaviour and stability of the starch gel. Tests have shown that a higher concentration is needed for modified wheat flour to obtain the same rheological properties as the potato reference starch. The storage stability is better for the reference starch than for the modified wheat flour. The degree of chemical substitution is proportional to the viscosity and last the stress factor has shown to be higher for the modified wheat starch gel than for the reference starch gel.

Environment and Economics
The environmental consequences of this production concept are extremely important, since the elimination of chemical waste water and a severe reduction of the energy consumption make the concept of the Cascade project favourable for the environment. The consequences will be analysed. Assuming competitive performance of the modified wheat flours in the paper industry the perspectives are promising. The Stora company itself is using 70.000 tons/year at a cost of 200 millions SEK. A further economical analysis of the perspectives is a part of the Cascade project. So far an initial analysis of the market potential for the modified wheat flour. Has proved difficult, since the potential depends on a large number of parameters, including market regimes, minimum price settings, import levies, quotas, and production subsidies. It is still to early to conclude about the market potentials, but if we can fulfil quality requirement from the paper mills then based on the current production price there should be a market potential. Later in the project the environmental impact will be included in the analysis.