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FAIR-CT97-3527
Exploitation of the unique genetic variability of peas in the production of food and non-food ingredients |
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Contract No: | FAIR-CT97-3527 |
| Date Prepared: | 2002, March 2000 | |
| Source: | Final Report
Second Annual Progress Report |
Introduction
The following information is based on a longer final report. This public report contains a concise description of the efforts and results that have been obtained in the research tasks as defined in the technical annex.
The main objectives of the project have been:
By the end of the project the following aspects had been evaluated.
1: Genetics and multiplication A general conclusion is that 3 years are not enough for a plant-based project. An additional 4th year, as originally proposed, would have given more representative results. In addition the effect of a bad growing season, as experienced in 2000, would have been less. The multiplication of planting material has to start at least one year earlier than the other tasks in the project. In the current set-up of the project, the time to explore the final applications was too short. On the other hand, the scale-up to 100 kg+ scale has been found not to be necessary: 25 kg+ scale was sufficient.
The provision of the lam materials in the project has gone wrong, although the multiplication has succeeded. The initial multiplication of the double mutants worked out quite well; however, the amount of seeds that was left for further research and multiplication was too small. The field trials have been a success: for the first time a sound scientific evaluation can be done, since near-isogenic lines were available. Unfortunately, 2000 was a very bad growing season. Furthermore, the growers/farmers still have to be convinced that wrinkled peas can give sufficient yield. The current prejudices against wrinkled peas are comparable with those existing against leafless peas a few years ago. Farmers are looking for more yield; to convince them about the potential of these wrinkled pea lines more agronomic work is necessary, e.g., with growing studies in the southern hemisphere and production under glass.
2: Chemical and biophysical characterisation For this task all milestones have been achieved. One conclusion from this task is that a genetic control of structure and functionality is possible. Once again, the use of near-isogenic lines made it possible to look at these effects. Although the mutations were aimed at modification of starch properties, the protein properties were affected too (pleotropic (indirect) effect). With the new insights gained on the relation between genetics and starch properties, a lot of the existing literature on this topic can be judged as wrong. With the knowledge gained in this project it is, in principle, possible to create starch with tailor-made properties. However, the question as to which starch properties are specifically desired still remains unanswered in most cases. Furthermore, it is necessary to combine the pea current characteristics with other genetic backgrounds (at the moment only one genetic background is studied). This may also give convincing results for the growers of peas (yield, stem stiffness, etc.).
Most of the characterisations were done on lab-scale; however, another new feature in this subtask was the comparison of the characteristics of starch isolated on lab-scale with that isolated on pilot scale. For the proteins, unfortunately the pilot scale isolation procedure led to a loss of the vicilin fraction.
For the future is it necessary to relate the results of the current characterisation to "real" functional properties:
For this, however, a large new project has to be set up, comparable with the current project.
3: Fractionation The dehulling activities in this subtask were complicated by the fact that the relevant partner was not able to handle the relatively small amounts of material that was available in the project. As a consequence, dehulling became an integral part of the fractionation process, using a procedure of milling and sieving/air classification. The initial breaking of the peas, appeared to be a surprisingly good starting point for the dehulling process. The wrinkled nature of the peas was found not to be an obstacle for the dehulling process. The efficiency of the wet separation process was greatly improved by the removal of the husks. With the process used it was possible to handle all the pea mutants investigated. The initial alkaline extraction method used did not affect the protein functionality, whereas the starch properties were modified. The enzymatic treatment currently used did not lead to modification of starch properties, as indicated by the comparison of samples obtained via lab and pilot scale experiments in Task 2.
An applied drying method was found acceptable for the starch fraction, but not for the protein fraction (temperature too high). In addition drying of the fibre fraction was found to be very complicated, due to its sticky nature. From a scientific point of view it is a pity that only one wet protein isolation method (i.e., iso-electric precipitation) was studied, also because this method gave rise to the loss of the vicilin fraction. Comparison with protein isolation via membrane filtration is essential, since the latter method is applied as an (industrial) isolation process.
The insight gained into the relation between the pea composition and the results of the dry fractionation research has resulted in clear "design rules" for peas to be matched to dry separation methods. The dispersion of the pea flour was found to be highly dependent on the pea composition. In the subtask of dry separation only the combination of milling and air classification was studied; initial trials on the use of electrostatic separation methods were not successful. The protein fraction obtained via air classification can, depending on the purity, compete with either soy flour or soy concentrate. The best most promising application of the starch fraction seems to be as the starting material for the wet isolation process. Further research is needed to find out whether these two processes can be coupled.
4: Functionality and application This task experienced the difficulty of being at the end of the chain. The fact that this project was dependent on a number of growing seasons was an additional complication, further complicated by the fact that the project funding was reduced from 4 to 3 years while the start and end of the project were not synchronised with the growing seasons. As a consequence, not much time was left for a full and comprehensive evaluation of the functionality of the different components. Further, the evaluation of the results and coupling to the genetics/multiplication research tasks were not optimal. The determination of the basic functional properties of the protein fraction (emulsifying capacity and activity, solubility and oil binding) illustrated that the properties of the different mutants do not differ much from what is known for "normal" peas. Furthermore, these properties resemble those of soy (however, when speaking about these proteins we normally refer to proteins in the denaturated state).
Pea proteins may have the advantage above soy proteins of being outside the GMO-discussion. This matter, however, has lost most of its relevance since nowadays suppliers are giving guarantees of products being GMO-free.
Results suggest that indicated that applications for use in, for example paper, should not be underestimated. These tests do not consist of simply changing just one parameter, but require a full optimisation of the whole process.
Some results indicated that pea proteins are not so interesting for cosmetic applications as originally expected. Furthermore, the smell/off-flavours of the pea proteins used could limit their application.
The results of the work on thermoplastic processing and film formation just give rough indications of the potential of pea starch and protein for these applications. The work was too limited to be able to draw clear conclusions. Unfortunately, due to changes in personnel, evaluation of the functional properties of the fibre fraction was not possible.
5: Economic evaluation The difficulties described under point 4, of being at the end of the chain also apply to the activities in this area. A techno-economic evaluation is difficult so long as the actual applications are not clearly defined. The starting point for the evaluation was, therefore, a comparison with soy proteins. The economic evaluation gave an estimation of the cost price with an accuracy of +/- 30%. A similar evaluation was carried out for a wet isolation process, although the exact figures are probably not quite accurate, they still give a good indication.
6: Co-ordination of the project No great difficulties were experienced in co-ordinating this project. However, it would have been nice if there had been more time for visiting all the partners in the project. In this way various difficulties encountered could have been solved at an earlier stage.
Objectives
The main objectives of this project are to exploit the unique genetic variability available for peas in the production of functional ingredients for food and non-food applications and to contribute to the creation of a stable market situation for the pea crop in the EU.
Specific research objectives within ties project are:
Activities
To achieve these objectives, work is carried out on 5 specific research tasks:
The research covers novel pea genotypes that have seed components with a broad range of functional properties as well as an assessment of the agronomic and economic aspects of their production. Existing dry and wet fractionation technologies have been adapted for fractionation of the seed components. Wherever possible the cheaper and more environmentally friendly dry separation technology is preferred. Raw materials and isolated fractions are being thoroughly characterised for their chemical, physical and functional properties. Novel and improved processing technologies, e.g., thermoplastic processing of starches, are being developed to make the pea seed constituents applicable for a wide range of food and non-food applications.
Progress
In the second year of the project, the work on genetics and multiplication of the newly develop pea lines was continued. The WT, r, rb and r/rb lines (already distributed to the partners in the first year of the project) were evaluated for their seed yield and quality in field trials. The results indicated that the yield penalty for the new mutants is low, which is unique for wrinkled peas. The rug4 and rug5 lines were multiplied to 50-kg scale and distributed for fractionation studies to the partners at the end of year 2. The remaining lam-mutant line was multiplied to at least 2.5-kg level. In addition, a selection was made for the double mutants which will be further investigated in the third year of the project.
Chemical and physical characterisation involved the continuation of the assessment of starch properties (granule structure, amylose content, crystallinity and gelatinisation) for the rug3, rug4, rug5 and lam mutants. The protein composition of the WT, r, rb and r/rb pea seeds was determined, as well the composition of the protein isolates as obtained by wet processing of these lines. Fibre content was determined for the WT, r, rb, r/rb, rug3, rug4, rug5 and lam pea mutants and compared with 2 commercially available lines.
The fractionation, functionality and application studies, so far limited to commercially pill available pea lines, were extended in this second year of the project to the WT, r, rb and r/rb lines. Fractionation studies involved the application of a newly developed wet process to obtain (pure) starch, protein and fibre fractions, as well as the application of a combination of milling and air-classification to obtain starch and protein enriched fractions. The method developed to predict the milling performance of pea lines based on the measurement of individual peas in a texture analyser, was evaluated on its usefulness on the WT, r, rb and r/rb pea lines.
Functionality and application studies involved a continuation of the work on thermoplastic processing of pea starch (with a focus on the influence of amylose content on the structure and properties of the thermoplastic starch), the application of pea proteins for micro- encapsulation purposes (the encapsulation of lipophilic components into pea protein microspheres and capsules) and pea starch for paper-making (determination of retention and dry strength of cationic samples of commercially available pea lines). Initial application studies were performed to determine the functional properties of the fibre fraction (water and fat binding of different fibre fractions). The functionality and application tests are experiencing the difficulty of being at the end of the chain "multiplication - processing - functionality and application", and are, therefore, slightly behind schedule.
Achievements
In year 1 and 2 of the programme, seeds from the WT, r, rb, r/rb, rug3, rug4 and rug5 lines have become available at a 100 kg+ level for further application studies. The lam mutant line has become available for further multiplication on a 2.5 kg level. Double mutant lines are currently selected for further multiplication and fundamental studies. Using different biochemical and physical characterisation methods, the composition and properties of the starch, protein and fibre fractions of the mutant lines are determined. Field trials have indicated that the yield penalty for the new mutant lines is low. The new methods that were developed for wet and dry fractionation of the peas have proven to be applicable for the production of (starch, protein) isolates and concentrates from the new pea varieties. Research on thermoplastic processing of pea starch has resulted in a better understanding of the influence of different process parameters, as well as the amylose content, on the mechanical properties of the resulting materials. The method to prepare pea protein microspheres for controlled release systems was optimised. Loading of these microspheres with the use of supercritical carbon dioxide appears a very promising method for the encapsulation of susceptible components. Reference experiments using commercially available pea starch have proven the applicability of pea starch for paper-making purposes.
Future activities
In the third year of the project, the rug4, rug5 and lam mutants will become available on a 100 kg+ scale for further processing. Field trials with the WT, r, rb and r/rb lines will be repeated during year 3 and extended to three sites, in order to increase the statistical significance of the results. The chemical and biophysical characterisation of the different genotypes will be continued, and also include a number of selected double mutants. Special attention will be paid to the effect of the wet isolation process on the composition and functional properties of the pea protein and starch fractions. Fractionation studies will first concentrate on the 3 rug mutants, which are now available on a 100 kg+ scale. At the end of the project, the lam mutant will also become available for further processing. With the results of these studies, the relation between genotype characteristics and separation performance can be determined, The application studies (so far restricted to commercially available pea lines) will be extended using the starch, fibre and proteins fractions of the NW, r, rb and r/rb lines which are now available. At a later moment in the year, these fractions will also become available for the 3 rug mutants in the project. Experiments on the functional properties of these fractions and their suitability for applications in paper-making, paper coating, thermoplastic processing and encapsulation. processing of thermoplastic starch will give an indication of the potential value of the newly developed pea lines. These results will be used for an economic evaluation of the new pea varieties, taking into the current market situation.
© Copyright 2006 Policy Statements
Updated
by CPL Press:
03/07/2007
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