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FAIR-CT97-3713
Calendula as agronomic raw material for industrial applications (CARMINA) |
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Contract No: | FAIR-CT97-3713 |
| Date Prepared: | April 2000 | |
| Source: | Progress Report |
Objectives
The main objectives are to:
Activities
The progress to date is presented below on a task by task basis
In general during the second year of this project has achieved the objectives set out in terms of primary production. More difficulties were encountered in the in the areas of processing, refining and application. New methods of seed processing were developed and used. These methods, based on dehulling and separation of the dehulled seeds into several fractions, produced 1500 kg of dehulled seed with an oil content of over 25 %. Difficulties were encountered in oil extraction. A new pilot hexane-extraction plant was used which was shown to be effective with traditional oil seed crops such as soya, rape, sunflower and linseed. However, with Calendula seeds an unusual problem occurred. The oil could be extracted very well, but there was a problem with the stream of oil seed residue (the meal). This meal became sticky during the hexane extraction and as a result it was difficult to transport the meal into the next stage where the solvent was removed. The linking pipe became completely blocked after only a few hundred kilogram of seed had been processed, as a result the 'continuous process' had to be stopped. This problem left the project with only a limited amount of oil that was not of the required quality.
To get around this problem a batchwise extraction of Calendula oil was used and gave around 50 kg of oil of excellent quality, which was used for development of some applications. However, insufficient oil was available for the work on surfactants application.
In addition, the pilot hexane unit was modified by temporary removal of the rotating valve where the blockage occurred. Obviously this is only possible as an experimental option, but it did allow production of a further 150 L of crude calendula oil. This was important since, although somewhat later than anticipated , it enabled the development of industrial applications to be scaled up. However, further work is required in order to optimise the extraction methods.
Experimental refining of the oil, with around 80 % recovery gave about 100 L of refined that can be used for application development in the third year. Another 200 to 400 L should become available during the third year.
The refined oil extracted batchwise (about 30 kg) was used for application development, resulting in the production of methylesters of calendula oil, which were then tested by addition at 10% to traditional alkyd paints. Tests indicated that the paint quality was more or less the same as for the traditional formulation (colour, wearing tests), but that paint drying and hardness development was slightly slower. However, this could be explained since the formulation should also have been modified, requiring an adaptation that was scheduled for year three of the project
Calendula oil was also tested as raw material for non-fogging polyurethane foams (without volatilisation of low molecular monomers that are otherwise used in polyurethane foam production). It proved possible to produce polyols from calendula oil and these polyols reacted with isocyanates to produce a foam. Several different proportions of polyols from calendula oil were tested. The resulting foams were not completely satisfactory, indicated that there was sufficient promise to justify further development.
Results
Plant Breeding One of the objectives is to select genotypes with improved seed retention and reduced flowering period to make harvesting easier and reduce seed loss in the field. Yield trials comparing genotypes selected in 1998 were evaluated by in 1999. Nineteen breeding lines, 2 parental accessions and 3 reference lines were evaluated, indicating significant variation in seed yield and oil content. The percentage of ripe seeds in August differed significantly, the reference lines being earlier and showing a higher % of ripe seeds than parental accessions. Most material showed mildew infection. The performance of new selections was compared to other material being grown by farmers and reference lines. The standard variety is high yielding and only two selections performed better. The oil contents of the parental accessions was lower than those of the standard varieties and the selected lines.
Seed yield performance Ten genotypes were evaluated for agronomic characteristics. Mildew had no effect on seed yield. There was a close relationship between mean seed yield from harvesting the entire crop and combine harvesting after desiccation. Genotypes differed significantly for harvest index which varied from 0.23 to 0.33 and was moderately correlated with seed yield, early flowering intensity in July and negatively correlated with plant height.
Quantitative genetic analyses 198 F2 plants were autopollinated, of which 10 failed to produce enough seeds for F3 evaluation. All the lines which failed to set seed had a high number of rows of rayflowers and probably had insufficient pollen containing disk flowers for successful pollination. F2 plants were evaluated for colour of ray and silk flowers, chlorosis, number of ray florets and mildew infection (which ranged from none to high). DNA isolation resulted in small, but sufficient, material for further use. Gel electrophoresis indicated significant amounts of RNA in the mix, which was removed using RNAase to the Restriction mix. Restriction, ligation, and pre-amplification did not cause any problems. As the test set gave good results, the protocol developed was applied to all F2s which gave higher DNA yields than from the test set. Parents of two F2s will now be tested with a large number of primer combinations, so that combinations which result in high polymorphism will be used.
Crop Physiology In the UK a known variety was sown at four seed rates and fertilised with two levels of nitrogen rates to create contrasting crop structures. Physiological measurements of crop growth included light interception by crop canopies, dry matter partitioning into leaf, stem, flower and seed plant components during growth and final seed yield. The crop was sown in early May, leaf area indices (LAIs) increased rapidly in July and remained steady in August. At the lowest seedrate LAIs remained low (max. 1.83), and below those required to optimise interception of solar radiation. This effect on reduced photosynthesis was reflected in reduced crop dry matter and seed yield at harvest. Maximum LAIs were achieved by the 40 plants square metre seedrate and there was no benefit from exceeding this seed rate. Final seed yields were also low at the highest (80 plants M2) seedrate, a similar result was found in 1998. In 1998, this was attributed to seed shedding, although this was not evident within plots in 1999. Hypotheses to explain these effects could include a reduction in plant population during the season due to competition, or that at higher density, mutual shading of lower seedheads within the canopy was reducing production efficiency.
Environmental effects Ten genotypes were successfully sown and harvested in replicated field experiments at six sites during 1999. Sites were located at Lelystad (NL), Starcross (UK), Wageningen-I (NL), Wageningen-2 (NL), Jena (GER) and Bazierge (FR). Experiment plots were assessed for a range of characters including seed yield and oil content. Seed oil yield in kg/ha was determined. Mean seed yield ranged from 1272 up to 1605 kg/ha across all six sites, with mean site yield ranging from only 862 kg/ha at Bazierge in southern France to 1900 kg/ha at Wageningen-2. The highest mean seed yield was produced by PRK, one of the varieties being grown by farmers. Seed oil content was low in PRK at 7.9%, but reached 21.7% in line 971188-4. Mean seed oil yield across all six sites and varieties was 290 kg/ha, but the best line, 971188-4 achieved 332 kg/ha across all sites and 472 kg/ha at one site.
The performance improvements of the new genotypes, in terms of seed yield and oil yield/ha, compared to the old type 'Hens and Chickens', demonstrates the achievements made in plant breeding within the project. The GxE experiments have also provided a valuable test of the potential of Calendula at contrasting European sites. Whilst there was significant variation between locations, the southern European site performing poorly, the data comparing genotypes across sites indicated good adaptation of the improved lines across all sites.
Seed separation and cleaning Seed cleaning and de-hulling tests continued in 1999 with the primary focus being the provision of high quality seed material for further processing by project partners, as described above
Calendula seed and flower-heads production Calendula was grown under commercial conditions at a field scale using two varieties, PRK and a line from PRI, by 8 farmers. In total 20. ha were cultivated producing 32 9 tonnes of seed for oil extraction. Seed oil content averaged 15.5% and seed oil yield/ha, 262 kg/ha. There was less variation in seed yield/ha amongst growers in 1999, which ranged from 1.4 to 2.2 t/ha, compared to the 1998 season. This was attributed to favourable dry weather conditions during the harvest period, and greater experience by growers in the technical aspects of crop management. A growers manual was produced by Cebeco, summarising key aspects in profitable crop management, covering aspects of sowing, fertilisation, harvesting, diseases and post-harvest management. For reasons of logistics it proved impossible to harvest flower heads in time.
Oil recovery The aim is to recover oil from dehulled calendula seeds, without changes in the fatty acid composition, on a scale of some hundreds of kg. This task was attempted in a continuous hexane extraction pilot plant, set up in 1998. In designing this plant processing constraints associated with calendula were taken into account, in particular, the need to limit the processing temperature at 80ºC. The continuous extraction plant was supplied by De Smet Company who assisted in the calendula processing trials. As indicated above some technical problems were encountered which have been partially solved, as indicated above. Because of these processing setbacks, which led to losses of material, it was not possible to draw up an accurate mass balance.
Flower-heads valorisation Since no flower heads were harvested, no activities were carried out for this task. This will be taken up again in the third project year.
Feed evaluation The objective of this task is to evaluate the potential of Calendula by-products as feed in livestock nutrition. The feeding value of Calendula residue after oil extraction was evaluated using the nylon bag technique. With this technique the degradation is followed during rumen degradation within the rumen of cattle using feed samples in nylon bags. Further standard chemical analysis was carried on ash, crude protein, cell wall components and mineral content. Results on protein degradation and cell wall degradation indicate variation in the water soluble fraction of organic material and protein in different oil seed residues of different experiments. Also the degradation rates differ widely between different oil seed residues. A strict relation was found between the organic matter digestibility and the level of lignin (ADL). With better dehulling the feeding value of the oil seed residue increases as more less degradable cell wall material is removed prior to oil extraction. The seed hull fraction has a low feeding value and would not be an interesting feed. The feeding value for cattle (net energy for lactation) and for pigs (net energy for pork production) was estimated for the different oil seed samples and oil seed residues. In scaling up the seed processing techniques to the level of several tons of seeds at a time a loss in the digestibility of the processed seeds and oil seed residue was found indicating that for improving the value added from by-products further optimization of the processing is necessary.
Oil refining and modification Classical solvent extraction and semi-physical refining (degumming-neutralisation-bleaching) resulted in Calendula oil of good quality of with acceptable specifications concerning free fatty acid content, unsaponifiables, phosphorus, chlorophyll and tocopherols. Further colour reduction could be achieved through deodorisation at temperatures from 200-225 ºC. However, this led to unwanted reduction in calendic acid content and perhaps does not need to be carried out. This needs to be confirmed in relation to quality required for the industrial applications.
Oil by-products valorization and oil-based resin production and evaluation No work was carried out on these tasks during this year.
Reactive diluent production and evaluation At labscale methylesters of calendula oil were produced. The reactivity of these can be improved, possibly by removing some tocopherols which reduce the reactivity. Tests indicate that diluting with methylesters of calendula oil gives comparable results as diluting with white spirit for which methylesters of calendula oil are a substitute. If the drying time (tag time) can be reduced methylesters of calendula oil can be used to replace white spirit in alkyd paint. This would give an option to reduce the content of volatile organic compounds (VOC) in alkyd paints.
(Non)ionic surfactants production and evaluation no work in this task has yet been performed.
Polyurethane foam (Puf) production and evaluation Calendula oil can be used to produce polyurethane foams. The oil may replace other raw materials from petrochemical origin. Calendula oil based PU-foams would show no emission of volatile compounds as is the case with PU-foams of petrochemical origin since there low molecular weight monomers are used as raw material. Calendula oil has a higher molecular weight (long chain fatty acid) and is therefore not volatile. In the process of PU-foam production first polyols have to be produced. It is here that the reactivity of Calendula beats that of many other vegetable oils. The methyl ester of calendula was used to synthesise stable polyurethane and other esters were also provided in order to improve the structure. Calendula containing polyurethanes can be expected to solve the problem of fogging because the C18 molecule is of advantage compared with technical polyols including components with shorter chain length.
Paint formulations based on methylcalendulate and calendula oil based resins This work was started only in the latter part of the second project year as this task was an addendum to the original Technical Annex. Some results on the potential of replacement of white spirit in alkyd paints by methylesters of calendula oil were obtained. These indicate that a 1 0 % replacement of white spirit is possible without a reduction in alkyd paint quality.
Changes in participants
The project has undergone a major change in the composition of the partnership as PPM and Stepan Europe left the project and a paint manufacturer joined the project (Van Wijhe). This latter partner is a real asset to the project since it enables the actual development of a new alkyd paint based on calendula oil.
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