Process for producing oils and defatted meal by means of solid/liquid extraction

Abstract

The present invention relates to a process for producing an oil and a defatted cake by solid/liquid extraction. The process comprises a step of solid/liquid extraction using a solvent comprising 2-methyloxolane and water.

Claims

1. A process for producing a polyphenol-rich crude oil from a biological substrate comprising a step of: a) solid/liquid extraction of the biological substrate with a solvent to obtain on the one hand a liquid fraction comprising the crude oil and the solvent and on the other hand a solid residue, wherein, the solvent is a mixture of 2-methyloxolane and water, the percentage of 2-methyloxolane by weight in the solvent in the extraction step a) is higher than 80%, and the percentage of water by weight in the solvent in the extraction step a) is from 0.3% to 20%.

2. The process according to claim 1, in which the biological substrate is selected from a plant, an alga, a microorganism and mixtures thereof.

3. The process according to claim 2, in which the biological substrate is a plant selected from almond, amaranth, peanut, argan, sea buckthorn, cashew tree, avocado, oat, borage, safflower, camelina, carrot, cocoa, cashew, hemp, colza, copra, cucurbit, cotton, croton, rosehip, fig, prickly pear, pomegranate, hop, illipé, jojoba, karite, flax, lupine, maize, hazel, walnut, coconut palm, poppy, olive, evening primrose, cabbage palm, paprika, pistachio, pepper, castor-oil plant, rice, musk rose bush, sesame, soybean, marigold, sunflower, Calophyllum inophyllum, madhuca, Queensland walnut, raspberry, blackcurrant, melon, grape, tomato, baobab, babassu, cranberry, chia, pumpkin, mustard, neem, Nigella sativa, niger, poppy, pecan, Perilla, Plukenetia volubilis, pumpkin, annatto, Taramira, apricot, plum, peach, wheat.

4. The process according to claim 1, in which the extraction step a) is carried out at a temperature of 20° C. to 100° C.

5. The process according to claim 1, comprising, in addition to the extraction step a), the following steps: b) recovering the liquid fraction comprising the crude oil and the solvent, and c) separating the crude oil and the solvent from the liquid fraction to recover on the one hand the crude oil and on the other hand the solvent.

6. A process for producing a refined oil comprising a step of refining the crude oil recovered in step c) of the process for producing a crude oil as defined in claim 5.

7. A process for producing a solid residue comprising a step e) of recovery of the solid residue obtained in step a) of solid/liquid extraction of the process as defined in claim 1.

8. A process for producing a desolvated solid residue further comprising a step f) of desolvation of the solid residue recovered in step e) of the process as defined in claim 7 to recover on the one hand the solvent and on the other hand the desolvated solid residue.

9. A process for producing a byproduct comprising a step g) of transforming the desolvated solid residue recovered in step f) of the process as defined in claim 8 to obtain the byproduct.

10. The process according to claim 9, in which the byproduct is selected from a flour, a protein concentrate, a protein isolate, a textured protein and mixtures thereof.

11. A crude oil derived from a biological substrate, said crude oil comprising a polyphenol and 2-methyloxolane, the concentration of polyphenol by weight being greater than or equal to 320 ppm.

12. The crude oil according to claim 11, in which the concentration of 2-methyloxolane by weight is from 0.5 ppm to 500 ppm.

13. A refined oil derived from a biological substrate comprising a tocopherol, the concentration of tocopherol by weight being greater than or equal to 1500 ppm.

14. The refined oil according to claim 13 further comprising 2-methyloxolane.

15. A solid residue derived from a biological substrate and comprising a polyphenol and a residual oil, wherein the concentration of polyphenol by weight is less than or equal to 3000 ppm and the concentration of residual oil by weight is less than or equal to 5%.

16. The solid residue according to claim 15 further comprising 2-methyloxolane.

17. A desolvated solid residue derived from a biological substrate comprising 2-methyloxolane, wherein the concentration of 2-methyloxolane by weight is below 1000 ppm.

18. A byproduct derived from a biological substrate comprising 2-methyloxolane, wherein the concentration of 2-methyloxolane by weight is below 1000 ppm.

19. The byproduct according to claim 18 selected from a flour, a protein concentrate, protein isolate, a textured protein, and mixtures thereof.

20. The process according to claim 1 wherein the mixture is a binary mixture.

Description

EXAMPLES

(1) In the examples given below, the method for determining the concentration of polyphenols by weight in the crude oils is the so-called “Folin Ciocalteu” method, described by Slinkard and Singleton in the work “Total Phenol Analysis: Automation and Comparison with Manual Methods” which appeared in the review “American Journal of Enology and Viticulture 28, No. 1 (1 Jan. 1977): 49-55”, with the modifications described below for using it on a 96-well microplate reader (FLUOstar Omega, BMG LABTECH, France).

(2) All the reagents and solvents used are of appropriate analytical grade.

(3) The polyphenols contained in the crude oil are extracted beforehand by the following method: 1 g of oil is diluted in 1 mL of hexane, and then the solution is extracted by 3 successive extractions with 3 mL of a methanol/water mixture (60 vol %/40 vol %). After each extraction, the 2 phases are stirred and then separated by centrifugation (10 000 rev.Math.min.sup.−1/10 min/20° C.) and the liquid water-alcohol phase is collected (any deposits, precipitates or solid particles potentially formed are not taken). The 3 water-alcohol phases are collected and then washed with 1 mL of hexane. The phases are separated by centrifugation and then the water-alcohol phase is transferred to a 10-mL graduated flask, and the volume is made up to the gauge mark with the methanol/water mixture (60 vol %/40 vol %).

(4) Using a micropipette, 20 μL of this solution is put in a well of the microplate, to which 80 μL of aqueous solution of Na.sub.2CO.sub.3 (anhydrous, Acros Organics) at 75 g/L is added. The same mixing is repeated in 7 other wells, i.e. 8 wells in total for 1 sample of crude oil analyzed. Then 100 μL of Folin-Ciocalteu reagent (Panreac AppliChem, ref. 251567.1609), previously diluted to 1/10 (v/v) in distilled water, is added to each well automatically by the automatic injector of the microplate reader. Reading of the absorbance of each well is performed by the UV-Visible detector of the microplate reader at 750 nm, at 25° C. after agitation for 1 h in the dark in the apparatus. In parallel, a calibration curve was constructed using 8 aqueous solutions of gallic acid (Sigma-Aldrich) in a concentration range from 0 to 100 mg/L of gallic acid, according to the same analysis protocol defined for the samples, except that the solution comprising the phase and the methanol/water mixture is replaced with one of the 8 aqueous solutions of gallic acid.

(5) Secondly, in order to remove the nonpolyphenolic compounds present in the oil, which may react with the Folin-Ciocalteu reagent (reducing sugars, proteins etc.), 5 mL of the solution of polyphenols obtained previously from the crude oil is acidified to pH=3.5 with 0.1 N HCl solution. Then 5 mL of distilled water and 1 g of polyvinylpolypyrrolidone (PVPP, particle size≈110 μm, Sigma-Aldrich) are added to this mixture in order to capture the polyphenols. The mixture is stirred mechanically for 10 min at 25° C. before being centrifuged at 10 000 rev.Math.min.sup.−1 for 10 min at 20° C. The supernatant is then taken and is then filtered using a filter-syringe (0.25 μm) before being analyzed according to the same protocol as the solution not treated with PVPP.

(6) The absorbance value of this solution treated with PVPP will be used as the “blank”; it will be subtracted from the value obtained previously.

(7) The absorbance value thus obtained, the mean value from absorbance measurement of 8 wells, from which the contribution of the nonpolyphenolic compounds is subtracted, serves for calculating the concentration of polyphenols by weight in the sample, from the equation of the calibration straight line. Taking into account the weight of oil used initially for the analysis, the concentration of polyphenols by weight in the sample is expressed in μg of gallic acid (abbreviated to EAG)/g of crude oil, or in an equivalent manner, in ppm.

(8) In the examples given below, the method for determining the concentration of tocopherols by weight in the crude oils and in the refined oils is standard NF EN ISO 9936: June 2016.

(9) In the examples given below, the method for determining the concentration of 2-methyloxolane by weight in the refined oil is applied using the conventional analytical chemistry technique called “GC-HeadSpace” (gas chromatography with sampling from the head space), according to the conditions described below. This analytical technique is known by a person skilled in the art to be suitable for analysis of volatile compounds contained in an oily matrix.

(10) All the reagents, solvents and materials used are of appropriate analytical grade. Firstly, 5±0.01 g of refined oil to be analyzed is weighed in a 20-mL bottle, specially designed for the “HeadSpace” technique (23×77 mm). Then exactly 15 μL of a standard solution (heptane at 40% v/v in octane) is added to the 20-mL bottle before it is sealed with a stopper equipped with a septum. The 20-mL bottle is stirred vigorously (Vortex) for 5 min before analysis. The operating conditions of the step of sampling and injection into the head space are as follows: instrument=“Turbomatrix HS40” (Perkin Elmer); desorption=60 min at 80° C., transfer line temperature=120° C., needle temperature=110° C.; injection volume=0.2 mL; hydrogen pressure=20 PSI. The operating conditions of the step of chromatographic separation are as follows: instrument=Clarus 500 (Perkin Elmer); column=DB1-30 m−0.32 mm−3.0 μm; injector temperature=150° C.; furnace temperature=40° C. (3 min) and then ramp of 10° C./min up to 110° C. (0 min). The operating conditions of the detection step are as follows: type of detector=flame ionization detector (FID); detector temperature=250° C., hydrogen pressure=11 PSI.

(11) The concentration of 2-methyloxolane by weight in the sample of refined oil analyzed is determined from the following formula: C.sub.MeOx=a*(A.sub.MeOx/A.sub.heptane) where C.sub.MeOx is the concentration of 2-methyloxolane by weight, A.sub.MeOx is the area of the peak corresponding to 2-methyloxolane, A.sub.heptane is the area of the peak corresponding to heptane (internal standard), and “a” is the slope of the calibration straight line for 2-methyloxolane established previously.

(12) The calibration curve was plotted, according to the classical principles of analytical chemistry, by adding known amounts of a solution containing 2-methyloxolane and heptane, to a refined oil not containing 2-methyloxolane, so as to obtain concentrations of the oil by weight of 0.51, 1.02, 2.05, 5.12 and 10.25 μg/g.

Example 1 According to the Invention: The Solvent Comprises 2-Methyloxolane and Water

Example 1-1: The Substrate is Soybean

(13) Crude soybean oil was extracted using an automatic extraction system of the Soxhlet type (Extraction System B-811, Büchi), from dehulled soybeans (Supplier: OLEAD, variety: ES PALLADOR, harvest: France, 2017, water content: 8.5%±0.3). The solvent used is a mixture of 2-methyloxolane (stabilized with BHT, Sigma Aldrich) containing 4.5 g of distilled water per 100 g of solvent.

(14) About 50 g of soybeans are ground using a cutting mill so as to obtain particles smaller than 1 mm.

(15) About 30 g of the powder obtained is weighed and put in a glass extraction cartridge suitable for the apparatus (Büchi). The cartridge is then put in the Soxhlet chamber and secured, in accordance with the instructions given in the user manual for the apparatus.

(16) Then 170 mL of solvent is put in the 250-mL receiving beaker provided for this purpose. Then the apparatus is set to operate according to the “Standard Soxhlet” mode, without rinsing or desiccation, with a number of cycles fixed at 20 and a heating power fixed at 10.

(17) Finally, the level detector is placed about 1 cm above the “high” level of the vegetable substrate and the condenser is supplied with cold water (8° C.).

(18) The solvent is then brought to the boil by means of the integrated heating plate. At the end of the 20 cycles, all the solvent containing the extracted oil is collected in the receiving beaker, whereas the solid residue remains inside the extraction cartridge.

(19) The solvent containing the extracted oil is left to cool for about 20 min at room temperature before being transferred to a 250-mL flask. The solvent is then evaporated using a rotary evaporator at reduced pressure (150 rev/min, 50° C.; 180 mbar, then 1 mbar to finish).

(20) The crude oil thus obtained is weighed and then cooled under a light stream of nitrogen for 10 minutes before being transferred to a sealed tube and then stored in the freezer at −20° C. until the analyses.

(21) The concentration of polyphenols by weight in the crude oil is presented in Table 1.

Example 1-2: The Substrate is Colza Seed

(22) The operating protocol is the same as in example 1-1, except that the starting substrate is whole colza seed (supplier: OLEAD; provenance: Gironde (France); harvest: 2016; water content: 5.2%±0.15) and the Soxhlet extraction cartridges used are made of cellulose and not of glass.

(23) The concentration of polyphenols by weight in the crude oil is presented in Table 1.

Example 1-3: The Substrate is Maize Seed

(24) The operating protocol is the same as in example 1-1, except that the starting substrate is maize seed (supplier: Avignon University; provenance: France; water content=7.25%), the Soxhlet extraction cartridges used are made of cellulose and not of glass, the level of the sensor was fixed so that the volume of the extraction chamber is about 175 mL, the extraction time was fixed at 1 h without setting the number of cycles and the heating power was fixed at 12.

(25) The concentration of polyphenols by weight in the crude oil is presented in Table 1.

Example 1-4: The Substrate is Cotton Seed

(26) The operating protocol is the same as in example 1-3, except that the starting substrate is cotton seed (supplier: Avignon University; provenance: Turkey; water content=7.99%) and the seeds were ground beforehand and sieved so as only to recover the kernel, without the cotton fiber.

(27) The concentration of polyphenols by weight in the crude oil is presented in Table 1.

Comparative Example 2: The Solvent is Hexane or Anhydrous 2-Methyloxolane

Comparative Example 2-1: Hexane

(28) The operating protocol and the biological substrates are the same as in examples 1-1 and 1-4, except that the solvent is hexane.

(29) The concentration of polyphenols by weight is presented in Table 1.

Comparative Example 2-2: Anhydrous 2-Methyloxolane

(30) The operating protocol and the biological substrates are the same as in examples 1-1 and 1-4, except that the solvent is anhydrous 2-methyloxolane.

(31) The concentration of polyphenols by weight is presented in Table 1.

(32) The results in Table 1 show that the process according to the invention using a solvent comprising 2-methyloxolane and water makes it possible to produce an oil richer in polyphenol than the oil obtained with hexane (reference solvent) and with anhydrous 2-methyloxolane.

(33) TABLE-US-00001 TABLE 1 Total polyphenols (μg gallic acid/g crude oil) 2-methyl- Biological oxolane + anhydrous 2- substrate water methyloxolane Hexane Soybean 1138 309 25 Colza 386 128 13 Maize 516 303 10 Cotton 394 195 52

Example 3: Effect of the Concentration of Water by Weight in the Solvent

(34) In this example, a crude oil is obtained by solid/liquid extraction starting from three different biological substrates with different solvents comprising 2-methyloxolane (stabilized with BHT, Sigma Aldrich) and distilled water, the percentage of water by weight in each solvent being 1%, 4.5%, 10% or 20%.

(35) The three biological substrates are: soybeans (supplier: OLEAD, variety: ES PALLADOR, harvest: France, 2017; water content: 8.5%±0.3), colza seeds (supplier: OLEAD; provenance: Gironde (France); harvest: 2016; water content: 5.2%±0.15), and sunflower seeds (provenance: Spain; supplier: L'ile aux épices; batch LPR22-1017; water content: 2.54%±0.12).

(36) The food oils extracted from these three oleaginous seeds are among the most produced in the world apart from palm oil.

(37) In this example 3, solid/liquid extraction is carried out by the extraction method called maceration under reflux, as this method is more suitable for the two-phase solvent than the “Soxhlet” method of extraction.

Example 3-1 According to the Invention: The Substrate is Soybean

(38) In this example 3-1, the biological substrate is soybean.

(39) About 50 g of dehulled soybeans are ground using a cutting mill in order to obtain particles smaller than 1 mm. 30 g of the powder obtained is weighed and put in a 250-mL glass flask surmounted by a condenser so as to be able to employ extraction under reflux.

(40) Then 170 mL of each solvent is introduced into the flask and then the contents of the flask are refluxed using a flask heater.

(41) The extraction time is fixed at 2 h starting from the first sign of reflux. At the end of the 2 h, the heating is switched off and the mixture is left to cool at room temperature for 20 min.

(42) Next, the flask contents are filtered on a bed of cotton so as to separate on one side the solid residue of the solvent containing the oil, collected in a new 250-mL flask. The solvent is then evaporated using a rotary evaporator at reduced pressure (150 rev/min, 50° C.; 180 mbar, then 1 mbar to finish). The crude oil thus obtained is weighed and then the traces of residual solvent are removed by a light stream of nitrogen for 10 minutes. The oil is transferred to a sealed tube and then stored in the freezer at −20° C. until the analyses.

(43) For each exemplified solvent, the concentration of polyphenols by weight is presented in Table 2.

Example 3-2 According to the Invention: The Substrate is Colza Seed

(44) The procedure for this example 3-2 according to the invention is identical to example 3-1 according to the invention apart from the substrate, which is colza seed.

(45) For each example solvent, the concentration of polyphenols by weight is presented in Table 3.

Example 3-3 According to the Invention: The Substrate is Sunflower Seed

(46) The procedure for this example 3-3 according to the invention is identical to example 3-1 according to the invention apart from the substrate, which is dehulled sunflower seed.

(47) For each example solvent, the concentration of polyphenols by weight is presented in Table 4.

Comparative Example 3-4: Hexane

(48) The operating protocol and the biological substrates are the same as in examples 3-1 to 3-3, except that the solvent is hexane.

(49) For each biological substrate, the concentration of polyphenols by weight is presented in Tables 2, 3 and 4.

Comparative Example 3-5: Anhydrous 2-Methyloxolane

(50) The operating protocol and the biological substrates are the same as in examples 3-1 to 3-3, except that the solvent is anhydrous 2-methyloxolane.

(51) For each biological substrate, the concentration of polyphenols by weight is presented in Tables 2, 3 and 4.

(52) TABLE-US-00002 TABLE 2 The substrate is soybean MeTHF denotes 2-methyloxolane Concentration of polyphenols Solvent by weight (ppm) Hexane (comparative) 58 Anhydrous MeTHF 266 (comparative) MeTHF + 1% H.sub.2O 396 (according to the invention) MeTHF + 4.5% H.sub.2O 699 (according to the invention) MeTHF + 10% H.sub.2O 813 (according to the invention) MeTHF + 20% H.sub.2O 787 (according to the invention)

(53) TABLE-US-00003 TABLE 3 The substrate is colza seed MeTHF denotes 2-methyloxolane Concentration of polyphenols Solvent by weight (ppm) Hexane (comparative) 6 Anhydrous MeTHF 58 (comparative) MeTHF + 1% H.sub.2O 124 (according to the invention) MeTHF + 4.5% H.sub.2O 177 (according to the invention) MeTHF + 10% H.sub.2O 240 (according to the invention) MeTHF + 20% H.sub.2O 270 (according to the invention)

(54) TABLE-US-00004 TABLE 4 The substrate is sunflower seed MeTHF denotes 2-methyloxolane Concentration of polyphenols Solvent by weight (ppm) Hexane (comparative) 49 Anhydrous MeTHF 52 (comparative) MeTHF + 1% H.sub.2O 140 (according to the invention) MeTHF + 4.5% H.sub.2O 181 (according to the invention) MeTHF + 10% H.sub.2O 171 (according to the invention) MeTHF + 20% H.sub.2O 84 (according to the invention)

(55) The results in Tables 2 to 4 show that the process for producing a crude oil according to the invention using a solvent comprising 2-methyloxolane and from 1% to 20% of water makes it possible to produce an oil richer in polyphenols than the oil obtained with hexane (reference solvent) and with anhydrous 2-methyloxolane.

(56) The total concentrations of polyphenols by weight obtained by the method of extraction called maceration under reflux (examples 3 and 4) are logically lower than those obtained by the “Soxhlet” method of extraction (examples 1 and 2). In fact, in contrast to the “Soxhlet” method of extraction, the solvent used in the method of extraction called maceration under reflux gradually becomes concentrated in the extract, thus limiting the extraction of the oil and of the polyphenols, in accordance with the laws of mass transfer known by a person skilled in the art.

Example 4: Production of a Defatted Cake

Example 4-1: The Substrate is Soybean Flakes and the Solvent Comprises 2-Methyloxolane and 4.5% of Water

(57) Solid/liquid extraction was carried out using an automatic extraction system (Extraction System B-811, Büchi), starting from soybean flakes (supplier: OLEAD, harvest: France, 2017, water content: 9.96%±0.20%, oil content=19.19%±0.20%, thickness≈1 mm). The solvent used is a mixture of 2-methyloxolane (Stabilized with BHT, Sigma Aldrich) containing 4.5 g of distilled water per 100 g of solvent.

(58) About 15 g of soybean flakes are weighed and put in an extraction cartridge made of cellulose suitable for the apparatus (Büchi). The cartridge is then put in the extraction chamber, in accordance with the instructions given in the user manual for the apparatus. The height of the level detector is set so that the maximum volume of solvent in the extraction chamber is equal to about 220 mL.

(59) Then 170 mL of solvent is put in the 250-mL receiving beaker provided for this purpose. Then the apparatus is parameterized so as to operate according to the “Standard Soxhlet” mode, without rinsing or desiccation, with a time fixed at 1 hour and a heating power equal to 12 so as to guarantee a number of cycles of filling-emptying of the extraction chamber equal to 7±1 per hour. The condensers are supplied with tap water, with a flow rate sufficient to guarantee condensation of the solvent vapors that will be generated.

(60) The solvent is then brought to the boil by means of the integrated heating plate. At the end of 60 min of extraction, all the solvent containing the extracted oil is collected in the receiving beaker, whereas the defatted cake remains inside the cartridge. The contents of the receiving beaker are then transferred to a suitable flask and then the mixture is desolvated according to the conditions stated in the preceding examples. The cartridge containing the defatted cake is recovered and then placed in a ventilated desiccator (Biosec type, model=TauRo) operating at a temperature of about 45° C. for at least 10 hours and in any case until the odor of the solvent is no longer perceptible. Once desolvated, the concentration of residual oil by weight in the defatted cake is determined according to standard NF EN ISO 734: February 2016, applied using the automatic extraction system (Extraction System B-811, Büchi) according to the “Continuous Extraction” mode corresponding to the method called “Twisselmann”, with a slight modification as the material to be analyzed is finely ground using a cutting mill instead of a micro-ball mill.

(61) The concentration of residual oil by weight obtained after extraction with 2-methyloxolane+water is presented in Table 5.

Example 4-2: The Substrate is Colza Flakes and the Solvent Comprises 2-Methyloxolane and 4.5% of Water

(62) Solid/liquid extraction was carried out according to the same protocol as in example 4-1, except that the substrate is colza flakes (supplier: OLEAD, harvest: France, 2017, water content: 8.21%±0.13%, oil content=23.03%±0.07%, particle size 3 mm) and the extraction time is 90 min.

(63) The concentration of residual oil by weight obtained after extraction with 2-methyloxolane+water is presented in Table 5.

Example 4-3: The Substrate is Sunflower Flakes and the Solvent Comprises 2-Methyloxolane and 4.5% of Water

(64) Solid/liquid extraction was carried out according to the same protocol as in example 4-1, except that the substrate is sunflower flakes (supplier: OLEAD, harvest: France, 2017, water content: 5.38%±0.24%, oil content=30.81%±2.59%, particle size 10 mm) and the extraction time is 90 min.

(65) The concentration of residual oil by weight obtained after extraction with 2-methyloxolane+water is presented in Table 5.

Comparative Example 4-4: Hexane

(66) The operating protocol and the biological substrates are the same as in examples 4-1 to 4-3, except that the solvent is hexane and the heating power is fixed at 9 so as to guarantee a number of cycles of filling-emptying of the extraction chamber equal to 7±1 per hour.

(67) For each biological substrate, the concentrations of residual oil by weight obtained after extraction with hexane are presented in Table 5.

Comparative Example 4-5: Anhydrous 2-Methyloxolane

(68) The operating protocol and the biological substrates are the same as in examples 4-1 to 4-3, except that the solvent is anhydrous 2-methyloxolane and the heating power is fixed at 12 so as to guarantee a number of cycles of filling-emptying of the extraction chamber equal to 7±1 per hour.

(69) For each biological substrate, the concentrations of residual oil by weight obtained after extraction with anhydrous 2-methyloxolane are presented in Table 5.

(70) TABLE-US-00005 TABLE 5 Concentration of residual oil by weight (g /100 g of dry matter) 2-methyl- oxolane + water anhydrous 2- Biological (according to methyloxolane Hexane substrate the invention) (comparative) (comparative) Soybean flakes 0.44 0.92 1.49 Colza flakes 0.67 1.08 2.22 Sunflower flakes 1.73 1.82 2.90

(71) The results in Table 5 show that the process for producing a solid residue according to the invention using a solvent comprising 2-methyloxolane and 4.5% of water makes it possible to produce a solid residue comprising less residual oil than the solid residue obtained with hexane (reference solvent) and with anhydrous 2-methyloxolane.

(72) This is particularly advantageous as it makes it possible to limit the losses of oil, facilitate removal of the residual solvent from the solid residue, increase the concentration of proteins in the solid residue, improve its stability in storage and facilitate its digestion by animals, in particular bovines.

Example 5: Pilot-Scale Test with Soybean

Example 5-1 According to the Invention: The Substrate is Soybean and the Solvent is a Mixture of 2-Methyloxolane and Water

(73) Extraction of crude soybean oil was carried out on a pilot scale in a 480-L filter-dryer (“Guedu” type). The soybeans (Supplier: OLEAD, harvest: France, 2017, water content: 12.2%) were prepared for extraction by conventional steps of dehulling and flaking so as to reduce the particle size and increase the accessibility of the extraction solvent. Then about 60 kg of soybean flakes were put in the filter-dryer, and then extracted by three successive passes of 2-methyloxolane (supplier=Pennakem LLC; unstabilized). The water content is different at each pass, respectively 1.44%, 2.85% and then 4.76%.

(74) The extraction temperature was on average 57±6° C., the solvent/solid weight ratio was fixed at 1.8 kg/kg and the extraction time at 15 min per pass, or 3×15 min in total.

(75) The solvent containing the extracted oil (mixture called miscella) was collected by filtration after each pass, then concentrated by means of a distillation column (80-85° C., at reduced pressure) and finally desolvated using a rotary evaporator (Hei-VAP ADVANTAGE, Heidolph, Germany) under vacuum, at 60° C. until there was absence of condensation of solvent, and then for 1 hour at 90° C. The desolvated extract was then centrifuged (4000 rpm/4 min) in order to remove a solid fraction extracted by the mixture of 2-methyloxolane and water, but which became insoluble in an oily medium. The crude oil obtained is then stored at −20° C. before refining or analysis.

(76) Once extraction has ended, the solid residue (defatted and filtered flakes) is desolvated in the same vessel (“Guedu” filter-dryer). The vessel is connected to a vacuum generator and then heated at 55° C. for 140 min, with injection of a nitrogen stream (14-18 L/min) to aid desolvation. Finally, the solid residue is discharged, spread on a plate and exposed to the ambient air for 1 day in order to remove the traces of residual solvent.

(77) The crude oil obtained then undergoes a conventional step of chemical refining comprising a step of degumming at neutral pH and then at acid pH, followed by a neutralizing step, a bleaching step and then a deodorizing step to obtain a refined oil.

(78) The concentration of polyphenols and of tocopherols by weight in the crude oil, and the concentration of tocopherols and of 2-methyloxolane by weight in the refined oil are presented in Table 6.

Comparative Example 5-2: The Substrate is Soybean and the Solvent is Anhydrous 2-Methyloxolane

(79) The operating protocol of the extraction is identical to example 5-1 according to the invention except for the following points: the solvent is anhydrous 2-methyloxolane (unstabilized), the solvent/solid ratio is 2.9 kg/kg, and the extraction temperature is 53±5° C.

(80) The concentration of polyphenols and of tocopherols by weight in the crude oil, and the concentration of tocopherols and of 2-methyloxolane by weight in the refined oil are presented in Table 6.

Comparative Example 5-3: The Substrate is Soybean and the Solvent is Hexane

(81) The operating protocol of the extraction is identical to example 5-1 according to the invention except for the following points: the solvent is hexane (extraction grade), the solvent/solid ratio is 2.2 kg/kg, and the extraction temperature is 52±3° C.

(82) The concentration of polyphenols and of tocopherols by weight in the crude oil, and the concentration of tocopherols by weight in the refined oil are presented in Table 6.

(83) TABLE-US-00006 TABLE 6 2-methyl- oxolane + water anhydrous 2- (according to Hexane methyloxolane the invention) (comparative) (comparative) Concentration of 106 Not 71 polyphenols by detected weight in the crude oil (ppm) Concentration of 2432 422 1010 tocopherols by weight in the crude oil (ppm) Concentration of 2335 344 908 tocopherols by weight in the refined oil (ppm) Concentration of <1 Not <1 2-methyloxolane detectable by weight in the refined oil (ppm)

(84) The results in Table 6 show that the process for producing a crude oil according to the invention using a solvent comprising 2-methyloxolane and 1.44% to 4.76% of water makes it possible to produce a crude oil richer in polyphenols than the crude oil obtained with hexane (reference solvent) and with anhydrous 2-methyloxolane.

(85) The results in Table 6 also show that the process for producing a crude oil according to the invention using a solvent comprising 2-methyloxolane and 1.44% to 4.76% of water makes it possible to produce a refined oil richer in tocopherols than the refined oil obtained with hexane (reference solvent) and with anhydrous 2-methyloxolane.