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AIR2-CT93-1817
Vegetable Oils with Specific Fatty Acids (VOSFA) Agricultural and Industrial Development of Novel Oilseed Crops |
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Proposal No: | AIR2-CT93-1817 |
| Date Prepared: | Februrary 1996, April 1998 | |
| Source: |
Project Progress Report Summary 3rd Consolidated Report Summary Final Summary Report UK MAFF Final Summary Report |
Project Progress Report Summary
INTRODUCTION
This is a continuing research project which commenced in January 1994 with the objective of further investigating a number of plant species which have been shown to have unusual specific fatty acids present in the feed oils. The group has selected five species after consultation with relevant industries. These are Dimorphotheca pluvialis and Lesquerella spp which contain hydroxy fatty acids; Euphorbia lagascae which contains epoxy fatty acids; Calendula officinalis; which contains fatty acids with conjugated double bonds; and Lunaria annua which contains long chain fatty acids. The fatty acids produced by these plants, all of which are suitable for cultivation under European climatic conditions, are of interest as synthetic intermediates for the chemical industry. It has been estimated that over 200,000 ha of these crops might be required to meet the potential market if suitable and effective methods of production and extraction can be developed. For this reason, the project is looking at the complete production chain from the field to the end user. This work has been divided into three section: primary production, processing and industrial applications.
OBJECTIVE
The objectives are shown in the Summary.
ACTIVITIES
Primary production: Germplasm regeneration and evaluation was carried out in the Netherlands on Calendula officinalis, Dimorphotheca pluvialis, Lesquerella spp. and Lunaria annua. Considerable variation was recorded between accessions of C. officinalis for many characteristics including earliness, seed shape and seed yield. The establishment of Lesquerella spp. was slow and suffered severe weed competition. Seed yields of L. grandiflora were, at 700-1400 kg/ha, superior to L. gordonii and showed a positive relationship to plant density. Hybridisation of annual and biennial accessions of L. annua was used to produce annual types. Satisfactory types were selected from F2 lines, but none of the F3 lines showed acceptable characteristics. Studies on the production potential and agronomy of C. officinalis, D. pluvialis, E. lagascae, L. grandiflora and L. annua were carried out in the United Kingdom. C. officinalis established satisfactory and matured more uniformly than in 1994. There were significant differences in growth, yield and oil content between accessions The maximum yield in 1995 was 2.5 t/ha. A number of crop safe and effective pre-emergence herbicides were identified, but the only potential post-emergence herbicide caused crop damage. Seed yields of D. pluvialis ranged from 790 to 910 kg/ha. The seed yield of E. lagascae ranged from 940 to 1360 kg/ha with high levels of oil and verdinic acid. The growth and yield of L. grandiflora was poor. L. annua established satisfactory in the summer of 1994, but suffered continuous plant loss throughout the year, there was no relationship between plant density and seed yield. Production potential was modest, differences between accessions were recorded. Metazachlor was identified as a crop safe and effective pre-emergence herbicide. The crop sown during the summer of 1995 suffered serious establishment problems. Studies on the production potential and agronomy of E. lagascae and Lesquerella fendleri were carried out in Spain. L. fendleri did not establish under field conditions, laboratory investigations are in progress to define its optimum establishment requirements. E. lagascae had sufficient winter hardness to grow and produce mature seeds as a winter crop and as a spring crop, provided it was sown in early spring.
Processing: Various oil recovery process steps for Euphorbia lagascae have been established, each with a typical oil and by-product quality. Dehulling after soaking, partial germination and drying of the seeds resulted in a decrease in cell wall material and an increase in oil and protein content. To date, the only technically feasible way of obtaining oil has been by hydraulic box pressing; extrusion failed. Enzymatic treatment of the E. lagascae seeds indicated the potential of this method. With C officinalis, cleaning seeds prior to a solvent extraction gave high seed losses. 265 kg oil of E. lagascae has been produced in a pilot plant, reflecting the technical ease of processing this seed. The quality of the recovered oil is good. However, the seeds and the transformation products are irritants so that specific safety measures have to be initiated. The pilot pressing plant will be equipped with dust and vapour removing devices. 44 kg oil of C. officinalis have also been produced in the pilot plant from flakes in a stainless steel facility. Work on feed properties of residues has been initiated in respect of anti-nutritional/skin irritating factors in Euphorbia.
Industrial Application: The possibility of replacing tung oil by Calendula oil, or other highly unsaturated oils, in existing formulations and the suitability of replacing mineral solvents by the alkylesters of unsaturated oils in paint were investigated. Two initial extractions of Calendula (containing 9.1% and 16.2% calendic acid) could not meet the required specifications. However, further extracts with 53.9 and 35.1 % calendic acid gave good results in styrenated resin. From both low calendic acid-containing oils, methylesters have been prepared and tested as reactive diluent in comparison with the methylester of tung oil. The drying characteristics of the Calendula methylesters were inferior to the tung oil methylester. A shortage of Lesquerella oil prevented its testing as replacement for castor oil in binders. After the addition of antioxidants and antiwear components E. lagascae oil has been tested using several standardised chemical and physical tests and found to be comparable with rapeseed oil, having some advantageous properties in respect of oxidation stability and load carrying capacity. C. officinalis oil studied in the pure form without additives did not perform very well.
3rd Consolidated Report Sumary
Introduction
The following information deals with the third year of the project, during which the following were the main objectives:
Some modifications were made to the anticipated work plan. In particular, due to toxicity problems associated with processing of Euphorbia seeds, this activity was postponed until more information was available about the health risks. Cultivation of this crop, however, continued. It should also be noted that one of the original participants (UNICHEMA) withdrew from the project.
It was decided to put more emphasis on research related to Calendula, Lunaria and the toxicity of Euphorbia.
Achievements
The following are noted:
Pilot scale seed production of all five crops.
Seed processing and
shipment of seed-stocks to pilot extraction plant
Breeding research on
Dimorphotheca and Lesquerella
Initial breeding research on
Lunaria and Calendula
Evaluation of yield and oil production
potential, measurement of plant establishment, development, structure, disease
and pest incidence for selected crops.
Screening a range of potential
herbicides for crop safety and efficacy for selected crops.
Determining
sowing date and plant population for selected crops.
Research on the impact
of the pre-treatment of the seed, solvent and extraction conditions during oil
recovery on the oil yield and quality.
Characterisation of the oil.
Research
on the impact of the pre-treatment of the seed and/or treatment of the defatted
seed/flakes on the quality of the seed meal.
Production of oil and seed
meal.
Chemical characterisation of the by-products and research on the
availability of nutrients.
Synthesis of oil based resins based on new oils.
Testing these resins in paint formulations.
Development of additive
based on the vegetable oils.
These are discussed in more detail, section by section, below.
Primary production
Calendula officinalis The evaluation
of germplasm regeneration indicated considerable variation between and within
accession in seed yield, flower characteristics and seed shapes, giving
expectation for rapid production of improved genotypes. Variation in oil content
was relatively small and all accessions showed a long flowering and seed set
period, improvement of these characteristics are important but are likely to
require alternative breeding techniques. Field evaluation of a number of
accessions again in south west England produced acceptable combine harvested
yields, although an infestation by Heliothis peltigra introduced
increased variability. The flowering and seed set period was extended, in a more
average rainfall year, making the identification of the optimum desiccation
timing difficult. A commercial crop in The Netherlands, suffered significant
plant loss caused by frost damage which necessitated partial re-drilling. This
resulted in an increased range of plant maturity, causing harvesting problems
and a disappointing yield.
Dimorphotheca pluvialis More progress has been possible in selection for a procumbent rather than an erect plant habit, which could improve harvestability but seed yields were low and not affected by plant architecture. Initial results indicated that selection for flowering date is possible and that yield is positively related to early flowering. Calculation of heritabilities from these studies have given very variable results, making it difficult to give guidelines for selection methods. Markers have been identified which will enable an estimation to be made of the proportion of self and cross pollination in the species. Field evaluation in south west England indicated satisfactory plant growth but the extended flowering and seed set period required three harvests, to produce a yield of 500 kg/ha, containing modest oil levels.
Euphorbia lagascae Under Mediterranean conditions establishment was best under winter sown irrigated conditions and poorest following spring sowing. Soil conditions were thought to be the major causative factor. Emergence was protracted increasing within crop variability. Although individual plant size and yield declined with increasing plant density, the highest plant density produced the highest yield per unit area. Oil and vernolic acid content was not affected by any of the husbandry factors investigated. The potential of the winter grown crop is about 5t/ha under irrigation and 1 .5t/ha under rain-fed conditions. In south west England the crop grew well and despite the shattering nature of the species, harvested yield was again over 1t/ha. The crop responded to removal of weeds by hand, but only pendimethalin, isoxaben and metazachlor gave high levels of weed control and a yield response.
Lesquerella spp. Under Mediterranean conditions establishment has been identified as the major problem with Lesquerella fendleri, and in addition to 1995/6 frost killed most of the emerged seedlings. To eliminate the frost risk earlier sowing is required, which will prevent the crop being grown under rain-fed conditions. Field performance of Lesquerella grandiflora in south west England was again poor and seed oil content was modest. The species responded to hand removal of weeds but the residual herbicides applied caused plant damage. Only post emergence benazolin+clopyralid produced a yield comparable to hand weed control.
Lunaria annua Evaluation of biennial and annual types and a cross breeding programme are in progress. Accessions were identified which flowered following sowing in early August but none which flowered when sown later. The flowering threshold appeared to be the presence of 8 leaves in November. Altenaria and Albugo candida occurred, differences due to accession and sowing date were identified. Highest yield was 1.4t/ha. Annual lines grew satisfactorily and differences in disease resistance, maturity and yield was recorded. Field evaluation is in progress in south west England but dry conditions in 1995 caused establishment failure. In 1996 May sowing produced the best establishment due to improved moisture availability, but metazachlor proved ineffective in providing summer long weed control. Small differences were recorded between accessions in seed oil, erucic and nervonic acid content
Processing
Most of the lab-scale research activities concentrated on Calendula
and to a lesser degree on Lunaria and Lesquerella. This was
due to the promising prospects for the oil as a raw material for the coatings
industry and possibly for other applications. The other oil seeds involved (Lunaria
and Lesquerella) remain under development or are regarded as
uninteresting (Dimorphotheca and Euphorbia). The experiments
with Calendula have been related to seed cleaning and seed pre-treatment
tests aimed at improving the oil separation process and the nutritional value of
the meal. Development and testing of the seed cleaning process, based upon a
breaker-unit and a classifier, was successful although further optimisation of
the process conditions is necessary. From here on process scaling-up is
relatively easy. Oil recovery from Calendula can be accomplished by both
expelling and solvent extraction. Expelling provides a high oil quality (good
colour and stability) but disappointing oil quantities. Extraction gives high
oil quantity (low residual oil content in the meal) but moderate oil quality
(dark colour and moderate stability). Oil quality improvement (pigments removal)
by adsorbent bleaching can be achieved but requires optimisation. About 84 kg of
Calendula oil has been produced on pilot-scale by direct extraction.
Although calendic acid is heat sensitive, the initial fatty acid composition can
be preserved. Solvent recovery from the micella is a process key-point.
Temperature and residence time need to be carefully controlled during the
process to prevent calendic acid deterioration. The oil expelling experiments on
lab-scale with Lunaria and Lesquerella were unsuccessful. It is
considered that it may be possibly to improve oil separation by adjusting the
geometry of the continuous expeller and/or optimising the seed priming or
pre-treatment process. A further research programme will also be directed on oil
expelling and seed pre-treatment allowing processing by percolation extraction.
However, 185.3 kg of Lunaria oil has been produced on pilot-scale. Lunaria
seems easy to process by expelling with a different type of seed press,
although further testing is necessary with other seed batches to study the
crushing parameters. Solvent extraction of the cake does not seem to cause any
problems. The experiments with Euphorbia have been postponed to allow a study of
the possible toxic effects of certain compounds present in the seeds. After
evaluation of the health risks further experiments may be performed.
Pre-treatment of the seeds to remove these compounds will also be considered.
In addition to the investigations on oil separation and characterisation, press cake or meal was evaluated for its feeding qualities for livestock. To date the influence of growing conditions and the seed processing variables, two factors affecting by-product quality, have been given particular attention. Analyses performed in the residues indicate that both Lunaria and Lesquerella by-products displayed properties of interest for utilisation as feed ingredient. These properties include: a moderate fibre content, 25-40% protein and an in-vitro OM digestibility of 65-70%. Considerable variation was observed in the fat contents of the seeds, particularly in Lesquerella. This variation may coincide with the variation in composition of the fat-free mass. Consequences for digestibility seem limited as a whole, but there is evidence for location effects on residue characteristics. Euphorbia residues of samples obtained from Spanish experiments showed higher (highly lignified) cell-wall and lower protein contents than the samples obtained from the Netherlands. The digestibility of the residues is unsatisfactorily low; the Spanish samples tended to be lowest. Dimorphotheca seed residues were low in protein and high in fibre, making them unattractive in animal feeding, unless further processing succeeds in (partial) removal of seed coating. Additional fibre analyses in residue samples provided further information for explanation of the observed differences in digestibility.
Industrial Application
The oils obtained were tested for two
industrial applications, coatings and lubricants. Natural regeneration and the
environmental friendly character makes them attractive substitutes for chemical
raw materials. The solvent extracted Calendula oil (containing 53.9% and
35.1 % calendic acid) has been tested in a styrenated alkyd on pilot plant scale
(80 kg of solid material produced). Both products were quite dark in colour and
too low in viscosity. These results could be due to the fact that the oils were
not refined prior to the application tests. The Calendula oils were
compared with tung oil (in present use) in a resin on tung/linseed oil/phenolic
basis. Solvent extracted oils were too dark in colour but the cold pressed oil
was in accordance with specifications. The reactivity of the 3 different Calendula
oils was poor compared to tung oil. Technical properties (paint) of the
resins produced from solvent extracted oils were poor; the properties based on
the cold pressed Calendula oil were comparable with tung oil. Despite
the difference in the calendic acid content of various Calendula oils
hardly any difference could be observed in the end product properties. This is
maybe due to the non-refined nature of both oils. The colour of the processed
cold pressed Calendula oil was more or less according to the
specifications of the final products. The extracted oil was quite dark but is
suitable as a tung oil substitute in existing products:
After addition of functional additives such as antioxidants and anti-wear components the Euphorbia, Calendula, Lesquerella and Lunaria oils were tested according to several standardised methods to evaluate their lubricating performance. The test results of the new vegetable oils and rapeseed oil were compared to traditional lubricant oil in use. Oxidation and thermal stability of the Lesquerella and Lunaria oils were both acceptable. The VI of 126 obtained for Lesquerella oil was quite low. This was probably caused by the OH-group in the lesquerolic acid. The anti-wear behaviour of both oils tested on the VKA and SRV-tester gave satisfactory results. Calendula oil contains about 30 % Linoleic acid and 55,5 % Calendic acid and therefor the additive-free base oil performed rather poor in the oxidation stability tests. More impressive are the properties of the Euphorbia oil with a content of 63,6 % vernolic acid (C18:1 d 9 epoxy 12 - 13). Due to the present antioxidant components the oxidative stability is better compared to rapeseed oil. The neutralisation number (NZ) of 13 results from a relatively high of free fatty acids content. At the end of the oxidation stability test according to DIN 51586 showed that the NZ decreased from 8,5 to 2,1. This is extremely unusual for ester oils and can only be caused by the reaction of the free acids with the epoxy-group of the vernolic acid ester. Titration of the epoxy-group of the fresh oil and the oil obtained at the end of the test (312 h / 95 /C) indicated degradation of the epoxy group. Overall performance of the Euphorbia oil regarding oxidative stability and anti-wear behaviour was acceptable and within the range of oils comparable to Crambe. In some aspects Euphorbia seems to be an improvement on rapeseed oil. The biodegradability of the oils was satisfactory.
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