This invention relates to improvements in and relating to methods of plant oil production, to products of such methods and to their uses.

Plant seeds (by which term we include fruit and nuts) are a major source of oils (generally triglycerides) for use in foodstuffs for humans and other animals, in fuels, as lubricants, and for many other end uses.

In general, plant oil production involves crushing the seeds or fruit or nuts of a plant and optionally using solvent extraction (generally with hexane) to extract the oil from the crushed material, the "meal".

Typically about 30 to 45%wt of the oil content of the raw seed material can be extracted in this way. The remaining meal, which contains proteins and

saccharides will then generally be used in animal foods, as a fuel source, or as landfill. As landfill, this can be a combustion hazard, especially with palm nuts.

The most commonly produced plant oils are palm, soybean and rapeseed oils, the total annual production of which is in excess of 100 million tons.

In view of the immense quantities of seed involved, there is a continuing need for improving the efficiency of the plant oil production process, both in terms of oil yield and the minimisation of waste products or the enhancement of the utility of the byproducts. The present invention is directed to this need.

We have found that, particularly with Brassica species such as rape, total oil production and by-product utilisation are enhanced if the seeds are heat-treated before, during or very shortly after being crushed, and if the crushed seed is subjected to enzymatic polysaccharide cleavage, i.e. using a carbohydrase. This treatment yields four valuable fractions: a shell (hull) fragment fraction; a proteinaceous fraction; an oil fraction; and a water-soluble saccharide fraction. These fractions can be used directly, but desirably are subject to further process steps to enhance their utility and value. Thus viewed from one aspect the invention provides a process for the extraction of plant oil from plant seeds, said process comprising the steps of: mechanically disrupting the seed core; digesting the disrupted seed core material in an aqueous medium with a carbohydrase; and separating the product into an oil fraction, a proteinaceous fraction and a water-soluble saccharide fraction; wherein before, during or within ten minutes of onset of the core disruption step the seeds are subjected to an enzyme-denaturing heat treatment step.

The enzyme-denaturing step serves to prevent enzymes released by seed core disruption from breaking down valuable components of the seed. In the case of Brassica species, for example, seed crushing causes myrosinases in the seed to break down valuable glucosinolates.

The carbohydrase digestion step in the process of the invention serves to break down the molecular framework of the seed core material, allowing oils and proteins to separate out more efficiently. The product of the digestion step is a three-phase mixture: a liquid oil phase; a solid proteinaceous phase; and an aqueous water- soluble saccharide phase.

These phases may be separated from each other in conventional fashion, e.g. by settling and decanting, centrifugation, cyclone or other vortex separation, etc.

In an especially preferred embodiment of the process of the invention, seed shell fragments are removed before or during the carbohydrase digestion step to yield a fourth product fraction, a shell fragment fraction. If this is not done, the solid proteinaceous fraction will have a higher shell fragment content. While the shell fragment fraction may be used as a fuel or as a land-animal feed component, it is generally preferred to minimise its use in aquaculture feed.

Where the seed material used is a hard-shelled nut, the shell is preferably removed before the kernel is itself mechanically disrupted. Where the seed material is large, e.g. having a mode maximum dimension above 5mm, the seed material is preferably comminuted, e.g. chopped or shredded, before the heat treatment step. Where the seed material is small, e.g. having a mode maximum dimension below 4mm, the heat treatment itself may disrupt the seed casing (shell/hull), allowing some or all of it to be removed before the seed core is mechanically disrupted. Such shell fragment removal may be effected by sieving or by subjecting the seeds to a gas flow (e.g. an air or nitrogen flow) which blows off the shell fragments, e.g. for use as a fuel or a feedstuff component.

The heat treatment step is preferably effected so as to raise the temperature of the seed material to 80 to 130°C for a period of 2 to 7 minutes, preferably 90 to 120 °C for 3 to 6 minutes. This may be done by any convenient means, e.g. passage over a heated surface, through an oven, past a heating element, by heated gas (e.g. air or nitrogen) or, preferably, by microwave irradiation. This may be done before, after, or, preferably, during mechanical shell-cracking, e.g. using rollers. Shell fragment removal preferably is then effected. Where shell-cracking does not involve seed core crushing, the (preferably already heat-treated) seed material is then preferably crushed mechanically, for example using rollers or, less preferably, a press. Any liquid phase produced at this stage may desirably be removed, for example by passage over a perforated surface. Such a liquid phase is desirably separated into oil and aqueous fractions. Shell fragments are preferably removed from the crushed seed, e.g. using a gas blow as described above.

The crushed seed material is then preferably ground to a fine particle size, e.g. 5 to 25 micrometers, especially 10 to 20 micrometers, mode particle size, for example by wet-grinding in a water bath.

The mechanically disrupted, e.g. crushed and ground, seed core material is then preferably contacted with carbohydrases in an aqueous medium. While a single carbohydrase may be used, e.g. an amylase, it is preferred to use a cocktail of two or more carbohydrases to ensure thorough breakdown of starches and structural polysaccharides into mono-, di- and oligosaccharides. Suitable carbohydrases and carbohydrase mixtures are available commercially, e.g. as Viscozyme L (trade mark) from Novozymes AS, Denmark. Viscozyme L contains carbohydrases at a concentration of about 67000 lU/mL. Breakdown of the polysaccharides allows plant oil and water-soluble and water-insoluble proteins to be released more efficiently from the seed core material. The carbohydrase is preferably utilised at about 0.1-10 MlU/kg, preferably 0.5 to 8 Ml U/kg, especially 1 -4 MlU/kg, relative to the seed material. The quantity of aqueous medium used is preferably 1 :1 to 8:1 , especially 1 .5:1 to 5:1 relative to the crushed seed material on a volume by weight ratio (i.e. 1 :1 means 1 L to 1 kg).

The seed material is then digested in the aqueous enzymatic medium, for example for a period of 3 to 15 hours, preferably 4 to 9 hours, and at a temperature of 35 to 55°C, preferably 40 to 50°C.

Following digestion, the reaction medium is then separated to yield an oil phase, an aqueous phase, and a solids phase. Separation may be effected by any convenient technique, e.g. settling and decanting, centrifugation, cyclone separation, etc., or a combination of such techniques. In one embodiment a Tricanter (R) (Flottweg, Germany) is used. Each phase will of course contain some material from another phase and, if desired, intermediate phases may be separated to increase the purity of the other phases.

The aqueous saccharide fraction will contain water, water-soluble saccharides and other water-soluble components (e.g. peptides and glucosinolates) and fines, e.g. shell fragments, seed kernel fragments, insoluble saccharides, protein and oil droplets. It is especially preferred to treat this fraction to reduce the fines content, e.g. by sedimentation, filtration, centrifugation, cyclone separation, etc. Any oil phase thereby separating out can be removed. The solids recovered may be added to the proteinaceous fraction, used as fuel, or, preferably, recycled into the digestion step. The aqueous fraction, preferably following such a fines separation step, is preferably treated to extract charged water-soluble materials and water soluble aromatics, for example by the use of an ion exchange resin or by solvent extraction. Where the seeds used are of a Brassica species, separation of charged species will yield a glucosinolate fraction and an aqueous saccharide fraction.

Where a glucosinolate fraction is produced, this may be used as a source of glucosinolates for pharmaceutical or nutraceutical products, optionally after drying and further purification. This use and the resultant products form further aspects of the present invention. As some glucosinolate breakdown may occur in the process of the invention, it is preferred also to carry out a solvent extraction, for example using alcohols (e.g. methanol or ethanol), cyclohexane, acetone or THF, to extract useful such products, for example the anti-cancer compounds 3,3'-diindolylmethane and indole- 3-carbinol.

Suitable Brassicaceaea species for the present invention include Camelina sativa and Brassica species such as mustards, e.g. B. juncea and B. nigra and more particularly B.campestris, B.napus and B.rapa, i.e. rape.

The use of C. sativa is especially preferred since the resultant plant oil has a particularly high omega-3 oil content and is particularly suitable for human and animal feeds.

Rapeseed oil and rapeseed meal had limited utility in human or even animal feeds due to the presence of erucic acid and the sharp-tasting glucosinolates, until plant breeding (and genetic manipulation) led to the low erucic acid, low glucosinolate varieties known as canola. Several canola varieties are available commercially and represent the bulk of rape used for rapeseed oil production.

Although bred for its low glucosinolate content, we have surprisingly found that canola functions as a good glucosinolate source in the process of the invention. Nonetheless, the use of low erucic acid rapeseed of varieties other than canola is preferred.

Other plant seeds are rich in useful chemicals, such as the flavonoids in grape seeds, the anti-cancer agents in Indian jujube, vitamin B-12 in apricot seed kernel, etc.

Still other preferred plant seeds useful in the process of the invention include palm, soybean, sunflower, safflower, walnut, groundnut, etc.

The water-soluble saccharide fraction from the process of the invention, with or without a charged or aromatic species extraction step, can be used in land animal and poultry feed, optionally after drying. However, more preferably, it is fermented to produce alcohol, e.g. methanol, ethanol or butanol, using an alcohol-producing microorganism, e.g. a yeast such as brewers' yeast. Fermentation may be effected in a conventional fashion as can subsequent alcohol distillation. The alcohol produced may be used as a biofuel. If desired, fermentation may be preceded by acid catalysis to further break down any oligosaccharides present in the fraction, followed by pH adjustment to a value tolerated by the by the alcohol-producing microorganism.

One of the potentially most valuable fractions produced in the process of the invention is the proteinaceous fraction. Typically this has a very high protein content, e.g. above 40% wt, especially above 50% wt, particularly above 60% wt. This makes this fraction particularly suitable for use in aquaculture feed, a use which forms a further aspect of the invention. The protein content can be increased by filtration, rinsing, drying, sieving to remove shell fragments, and further digestion with carbohydrases. To reduce the content of phenolics, the dried proteinaceous fraction is preferably subjected to solvent extraction, e.g. with hexane or supercritical carbon dioxide.

The plant oil fraction produced in the process of the invention may be used without further treatment or may be subjected to further treatment, e.g. to remove fines (including aqueous droplets), to cleave the plant triglycerides, to transesterify such triglycerides, to hydrogenate unsaturated fatty acids, or to fractionate to yield oils of different fatty acid chain lengths. Contaminants soluble in water-missible labile organic solvents such as alcohols, ketones, etc, may be removed by addition of such solvents, particularly together with an aqueous phase, phase separation (e.g. by decantation or cyclone separation, etc), and subsequent solvent stripping.

The plant oils of the present invention have been found to have the following properties:

• Significantly less oxidation compared to other vegetable oils produced with traditional methods. This may be dependent on the variety of seed used.

• Low phosphorus content (e.g. less than 10 ppm, preferably less than 4 ppm), thus providing a highly refined oil or super degummed oil.

• A low sulfur content, less than 20 ppm, especially less than 10 ppm,

preferably less than 9 ppm, e.g. 2 to 6 ppm. • A low water content (e.g. less than 0.2%, preferably less than 0.07%).

• Acid value of less than 1.0, preferably less than 0.7.

• The oils may have good thermal properties and a high fire point/flash point compared to traditional fossil oils.

• A lower viscosity compared to traditionally produced vegetable oils.

Viscosity (at 40°C, cSt) is preferably less than 35 cSt, preferably under 32 cSt (without additives to lower viscosity).

• Dielectric Strength (I EC 156, kV/2.5 mm) of at least 48 (without any

additives to increase breakdown voltage).

The plant oils produced by the processes of the present invention and plant oils having any of the above properties form a further aspect of the invention.

The above properties lend the oils to many uses, for example in feed, cooking, as a biofuel, a hydraulic fluid, an insulating oil (e.g. an oil used in electrical devices such as oil-filled transformers, high voltage capacitors, fluorescent lamp ballasts, high voltage switches and circuit breakers, particularly a transformer oil). A low rate of oxidation of the oil is found during use in a transformer, when compared to traditionally produced oils. The fact that the oils have a low phosphorus content can improve the dielectric property, which is an advantageous property for use in electrical devices such as transformers. Moreover, the lower viscosity also renders the oils particularly suitable for use as insulating oils, e.g. transformer oils. The use of the oils of the invention in electrical devices, e.g. such as those mentioned anode, therefore forms a further aspect of the present invention.

The plant oil produced may advantageously be used in human or non-human animal feed, or for cooking. Especially preferably it is used in aquaculture feed preparation, particularly preferably in combination with protein produced in the process of the invention. In this way the animal-product (especially fish product) content of the resultant feed may be reduced, something for which there is a huge demand nowadays. In an another alternative, the plant oil product may be used as a biofuel. In an especially preferred aspect of the invention, the plant oil, mixed with mineral oil, may be used as a hydraulic fluid. The plant oil produced by the process of the invention has been found to be unusually suitable for this use. Where the plant oil produced is used in animal, especially fish, feed, it may be used as up to 100% wt of the lipid used to produce the feed, preferably at least 10%wt, more preferably at least 50%wt, particularly up to 90%wt, e.g. up to 75%wt. The total lipid, protein and carbohydrate contents of the feed may be conventional for the feeds for the animal recipient. Where the feed also contains protein produced by the process of the invention, it may be used as up to 100% wt of the protein used to produce the feed, preferably at least 10%wt, more preferably at least 50%wt, particularly up to 90%wt, e.g. up to 75%wt.

Where the plant oil produced is used in mineral oil containing hydraulic fluids, it can be used in a weight ratio, relative to the mineral oil (which can be one of those conventionally used in hydraulic fluids) of 1 :100 to 100:1 , especially 1 :10 to 10:1 , particularly up to 3:7.

Where the plant oil is used as an insulating oil, e.g. a transformer oil, it can be used alone or in combination with conventional insulating oils (which can be, for example, a mineral oil, a silicon-based oil, a fluorinated hydrocarbon) in a weight ratio, relative to the conventional oil of, e.g. 1 :100 to 100:1 , especially 1 :10 to 10:1.

The process of the invention is particularly suitable for bulk production of plant oils since it can be performed in a continuous manner, unlike the conventional pressing and solvent extraction techniques which are performed batchwise. Thus seed material may be fed continuously into a digestion reactor with the digested product being withdrawn continuously from the reactor. The digestion reactor may be a linear (tubular) reactor, however it is especially preferred to use a loop reactor. Where a loop reactor is used, it is preferred to recycle the solids extracted from the outflow steam into the reactor and to extract those solids on an occasional basis following a period during which material inflow to and material outflow from the reactor has been stopped. During normal operation therefore, the material inflow will generally comprise mechanically disrupted, e.g. crushed and ground, plant seed, water, carbohydrases, and recycled solids.

The preferred features of the invention described thus far also apply to the following aspects. The process of the invention is likewise particularly suited, especially when operated as a continuous process, for operation using as the raw plant material plant seed cake produced using conventional crushing processes for plant oil production - in this way the oil recovery from the seeds is further increased.

Similarly, the process, especially when operated continuously, may use as its raw material the crushed fruit pulp cake produced as a by-product in the production of fruit juices. Particularly where Brassica seed cake is used as the raw material, it is preferred that the seed crushing step in the preceding oil extraction process is accompanied by an enzyme-denaturing heat treatment step as described earlier.

Thus viewed from a further aspect the invention provides a process for the continuous production of plant oil wherein plant seed is mechanically disrupted, the disrupted seed is fed into a digestion reactor and digested therein in an aqueous medium using a carbohydrase, and a product flow comprising liquid plant oil, an aqueous solution of water-soluble saccharides, and solid proteinaceous material is withdrawn from the reactor and separated into a liquid oil fraction, an aqueous fraction and a solids fraction.

In a preferred embodiment, the aqueous phase of the stream withdrawn from the reactor, preferably before solids separation therefrom, is subjected to a counterflow, through an active or passive mixer, of a water-immiscible solvent, e.g. hexane, with the hexane outflow then being solvent-stripped and the solvent being recycled. In this way non-nutrients and valuable by-products can be separated out.

In an alternative embodiment, the aqueous phase of the stream withdrawn from the reactor is mixed with a water-miscible solvent and, preferably after solids removal, applied to an ion exchange column to cause retention of charged (especially negatively charged) non-saccharide components. The charged components may be recovered from the column conventionally and solvent-stripped to yield useful byproducts in concentrated form. The saccharides may be fermented to produce alcohols, e.g. for biofuels, optionally after solvent-stripping. Stripped out solvents may of course be recycled.

Similarly, the oil phase of the stream withdrawn from the reactor may be subjected to a counterflow of an aqueous solvent mixture comprising water and a volatile water-miscible solvent to strip out non-nutrients. The resultant oil phase may then be subjected to reduced pressure to strip out any entrained non-aqueous solvent. The volatile solvent may then be recycled.

Viewed from a still further aspect, the invention provides a process for the production, preferably for the continuous production, of plant oil wherein plant seed cake is fed into a digestion reactor and digested therein in an aqueous medium using a carbohydrase, and a product flow comprising liquid plant oil, an aqueous solution of water-soluble saccharides, and solid proteinaceous material is withdrawn from the reactor and separated into a liquid oil fraction, an aqueous fraction and a solids fraction.

Viewed from a further aspect the invention provides a process for the preparation of a plant oil, wherein plant seed is mechanically disrupted, the disrupted seed is fed into a digestion reactor and digested therein in an aqueous medium using a carbohydrase, and a product flow comprising liquid plant oil, an aqueous solution of water-soluble saccharides, and solid proteinaceous material is withdrawn from the reactor and separated into a liquid oil fraction, an aqueous fraction and a solids fraction; characterised in that said plant seed is seed of Camelina sativa, B. juncea, B. nigra, grape, Indian jujube, palm, soybean, sunflower, safflower, walnut, groundnut, or apricot.

Viewed from a further aspect, the invention provides a process for the production of plant oil, said process comprising mechanically disrupting a plant material (e.g. a plant seed, plant seed core, or plant seed cake), digesting the disrupted material in an aqueous medium with a carbohydrase, separating the product into an oil fraction (e.g. a liquid plant oil fraction), a solids fraction (e.g. a proteinaceous fraction) and an aqueous fraction (e.g. a water-soluble saccharide fraction) wherein the process comprises one or more of the following features:

(i) before, during or within ten minutes of onset of the core disruption step, the seeds are subjected to an enzyme-denaturing heat treatment step,

(ii) said process is continuous

(iii) said plant material is plant seed cake

(iv) said plant seed is seed of Camelina sativa, B. juncea, B. nigra, grape, Indian jujube, palm, soybean, sunflower, safflower, walnut, groundnut, or apricot. A preferred aspect of the processes herein described is the use of a closed production line, and/or use of nitrogen and/or similar gases (e.g., other inert gases such as argon) throughout the process or reactor, e.g. in the production line, equipment and tanks (production and storage). This displaces air before production, and results in a lower oxidation of the oil.

Other preferred aspects for the processes of the invention are described above.

Viewed from another aspect the invention provides the use of plant oil, and preferably also plant protein, produced by a process according to the invention in an animal feed, especially an aquaculture feed.

Viewed from a still further aspect the invention provides the use of plant oil produced by a process according to the invention in a mineral-oil-containing hydraulic fluid.

Viewed from another aspect the invention provides a hydraulic fluid comprising a mineral oil and a plant oil produced by a process according to the invention, preferably a rapeseed oil.

Viewed from a still further aspect the invention provides the use of plant oil produced by a process according to the invention in or as an insulating oil or a dielectric coolant, e.g. as a transformer oil.

Viewed from another aspect the invention provides an insulating oil or a dielectric coolant, e.g. a transformer oil, comprising a plant oil produced by a process according to the invention, preferably a rapeseed oil.

Viewed from still another aspect the invention provides an animal feed, e.g. a mammalian land-animal feed, a poultry feed or, preferably an aquaculture feed, in particular a vertebrated fish feed, especially a carnivorous fish feed, in particular a salmonid feed, comprising protein and lipid, characterised in that said lipid comprises a plant oil produced by a process according to the invention, in particular as at least 10%wt of the lipid content thereof, and/or said protein comprises a protein produced by a process according to the invention, in particular as at least 10%wt of the protein content thereof.

The feeds according to the invention will typically contain 5 to 20%wt lipid, especially 8-15%wt. The protein content is desirably 30-75%wt, especially 40- 65%wt, particularly 45-60%wt. Such feeds desirably also contain vitamins and minerals and can be produced by conventional techniques, e.g. extrusion and pelletisation, optionally followed by impregnation with water and/or lipids. For aquaculture feeds, the carbohydrate content is preferably kept to a minimum, e.g. below 25%wt, especially below 20%wt. A certain amount of carbohydrate, e.g. at least 5%wt, may be desirable to function as a binder.

Viewed from another aspect the invention comprises a glucosinolate composition comprising a glucosinolate extracted from a water-soluble saccharide composition produced by a process according to the present invention.

In a particularly preferred embodiment, the glucosinolate composition according to the invention is in the form of a nutraceutical or pharmaceutical composition comprising at least one physiological carrier or excipient.

Viewed from another aspect the invention provides an animal feed, for example a feed for a land-based animal, for example a human or another mammal such as pig, cow, sheep, goat, horse, donkey, camel, dog or cat, or poultry, comprising seed shell fragments produced by a process according to the invention, e.g. as up to 25%wt, preferably 1 to 10%wt, of the feed.

Viewed from another aspect the invention provides the use of an oil or alcohol produced by a process according to the invention as a fuel or fuel additive.

Embodiments of the processes and products of the invention will now be described further with reference to the following non-limiting Examples.

Example 1

Rape seed processing Low-glucosinolate rapeseeds (Canola) were heated in a microwave oven at 750 W in portions of 120 grams for 1 minute in order to inactivate myrosinases and to make the hulls brittle. Thereafter the seeds were softly comminuted in a kitchen grinder in order to release the hulls from the seed kernels, and the hulls were carefully blown off by use of pressurized air. In this way about 10%wt of the seed dry matter was removed. The dehulled fraction was immediately milled by use of a coffee mill in order to get particles in the range 20 to 100 micrometer dimensions. 250 grams of this material were mixed with 750 mL deionized water and 7.5 mL of Viscozyme L (Novozymes) which according to the producer consists of beta- glucanase endo-1 ,3(4)-. The mixture was split into five containers. Each container was capped and incubated at 50°C for 24 hours. After the incubation, the slurry was spun at 5000 rpm for 10 minutes by use of a Heraeus Labofuge. This treatment generated five phases which in total gave: liberated oil (20 mL), an oil-protein-water emulsion (90 g dry matter), a water phase (450 mL), a protein-fibres phase (20 g dry matter) and at bottom rests of hulls (44 g dry matter). A similar test without enzymes yielded 2 mL liberated oil, 78 g dry matter oil-protein-water emulsion, 450 mL water phase, 69 g dry matter protein-fibres phase, and 65 g dry matter hulls. Thus, the enzyme generated more liberated oil, more emulsion and less protein- fibres. Moreover, the percentage of carbohydrates in the water phase was 1 1 °Brix with use of the enzyme as compared to 8 °Brix without the use of enzymes.

Example 2

Camelina sativa seed processing

The oil from dried seeds of Camelina sativa was extracted by use of water and Viscozyme L (Novozymes). 100 grams of seed was milled using a coffee mill to yield particles in the dimension range 20 to 100 micrometers. The seed material was suspended in 500 mL of deionized water and 5 mL Viscozyme L in a container which was capped and stored at 50°C for 5 hours with regular agitation. After the incubation, the slurry was spun at 5000 rpm for 10 minutes using a Heraeus Labofuge. In total, 5 mL oil was recovered from the suspension. Analysis revealed an oil composition including 39.5% linolenic acid (C18:3 n-3), 15.7% C20:1 , 15.4% linolenic acid (C18:2 n-6), 12.5% C18:1 , 5.0% palmitic acid (C16:0), and 2.9% erucic acid (C22:1 n-9).

Example 3 Glucosinolate concentration

Glucosinolates are separated from the aqueous fraction of Example 1 (or 2) by the use of a membrane element system operating at the ultrafiltration level. The filtrate is then passed over a nanofiltration element which yields the glucosinolates in a concentrated fraction (about 5-10% wt dry matter). 10 L of the concentrate is loaded onto a bed of 1 kg Amberlite IRA-67 in a 100x5 cm chromatography column. The loaded column is stripped using 5% aqueous ammonium hydroxide in methanol. The eluate is concentrated to dryness using a rotary evaporator (30 mbar, 70°C). The resulting dry mass is about 200g and about 50%wt glucosinolates.

Example 4

Bioalcohol production

The aqueous, saccharide-containing fraction from Example 1 (or 2), optionally after glucosinolate-stripping, and optionally after pH adjustment and/or organic solvent stripping, is fermented in a conventional fashion using brewers' yeast. Alcohol is then distilled off, again in conventional fashion.

Example 5

Aquaculture feed

Rape seeds are heated in a continuous microwave oven (e.g. Berstorff MW, 2100 mm x 400 mm x 160 mm, with a maximum effect of 21.6 kW) to inactivate myrosinases and to make the hulls brittle. Thereafter, the seeds are squeezed between stainless steel rollers to release the hulls from the seeds, and transported onto a perforated belt where the hulls are separated from the seeds by the use of an air-stream from below. 1000 kg of the resultant dehulled seeds are fed into a 5000L stainless-steel tank, containing 3000 L water and 30 L Viscozyme L

(Novozymes) at 45 °C. The tank is equipped with a Fryma wet mill, and the suspension is continuously milled for 4 hours. The mixture is then pumped into a tricanter (e.g. Flottweg) which splits the suspension into three phases: lipid;

aqueous; and solid. The lipid phase is worked-up using a separator. The solids fraction is resuspended in water (1 kg solids to 4 L water at ambient temperature), and mixed thoroughly using a Fryma wet mill. After 1 hour, the suspension is separated using a tricanter. The washed solids phase is drum-dried under vacuum to a moisture content of 10% wt. The concentrate obtained in this way typically has a protein content of 60% wt. The yields of lipid and protein from the rape seed is typically 70 and 50%wt, respectively. Both products are suitable for use in aquaculture feed. They may be mixed together in appropriate weight ratios or may be mixed with other lipid and protein sources, optionally containing lipid and protein, or lipid or protein, from the process.

Example 6 - production and testing of rape seed oil

Rape seeds were heated in a continuous microwave oven (Berstorff MW, 2100 mm x 400 mm x 160 mm, with a maximum effect of 21 .6 kW) to inactivate myrosinases and to make the hulls brittle. Thereafter, the seeds were squeezed between stainless steel rollers to release the hulls from the seeds, and transported onto a perforated belt where the hulls were separated from the seeds by the use of an air- stream from below. 1000 kg of the resultant dehulled seeds were fed into a 5000L stainless-steel tank, containing 3000 L water and 30 L Viscozyme L (Novozymes) at 45 °C. The tank was equipped with a Fryma wet mill, and the suspension was continuously milled for 6 hours (4 to 10 hours is suitable with a longer reaction time in the tank resulting in a lower phosphorus content and water content). The mixture was then pumped (temperature 90°C) into a tricanter/decanter (Flottweg) which split the suspension into two phases - oil and restproducts. The restproduct can be introduced to a tricanter in a second step of production, separating the suspension into three phases: lipid; aqueous; and solid.

The oil was tested in a commercial oil laboratory using the following standards: Viscosity: ASTM D 7043

Dielectric: I EC 156, kV/2.5 mm

Water content: ASTM D3828

The results showed the oil to have the properties described herein, e.g. a low water content (e.g. less than 0.2%); a lower viscosity compared to traditionally produced vegetable oils (e.g. viscosity (at 40°C, cSt) of less than 35 cSt, without additives to lower viscosity) and dielectric strength of at least 48 (without any additives to increase breakdown voltage).