Method for refining lipid phases, and use

Abstract

The invention relates to a method for gently eliminating odorous substances and coloring agents from lipid phases. Said method is easy and inexpensive to carry out and and can be employed for purifying lipid phases of various origins.

Claims

1. A method for reducing odorants and/or dyes from a lipid phase comprising the steps of: a) determining a phosphorus content of the lipid phase, testing for the presence of mucilages in the lipid phase, and b) performing a pre-purification step until the investigation of the presence of mucilages is negative and/or a phosphorus value is smaller or equal to 15 mg/kg, and c) adding an aqueous phase containing a compound having at least one amidino group or at least one guanidino group that have a partition coefficient (Kow) between n-octanol and water of <6.3, and d) preparing an intensive mixture of the lipid phase and the aqueous phase, and, wherein a intensive mixture is present when the water droplets in the lipid phase have an average diameter of 0.01 to 20 ?m, e) carrying out a centrifugal phase separation and removal of the aqueous phase containing the detached odorants and/or dyes; wherein the lipid phase are oils, fat or biodiesel; and wherein the compound having at least one amidino or at least guanidine group is arginine, or one of the following compounds ##STR00006## ##STR00007## ##STR00008## or a compound of the general formula (II) ##STR00009## wherein R, R, R and R are independently of each other: H, OH, CH?CH.sub.2, CH.sub.2CH?CH.sub.2, C(CH.sub.3)?CH.sub.2, CH?CHCH.sub.3, C.sub.2H.sub.4CH?CH.sub.2, CH.sub.3, C.sub.2H.sub.5, C.sub.3H.sub.7, CH(CH.sub.3).sub.2, C.sub.4H.sub.9, CH.sub.2CH(CH.sub.3).sub.2, CH(CH.sub.3)C.sub.2H.sub.5, C(CH.sub.3).sub.3, C.sub.5H.sub.11, CH(CH.sub.3)C.sub.3H.sub.7, CH.sub.2CH(CH.sub.3)C.sub.2H.sub.5, CH(CH.sub.3)CH(CH.sub.3).sub.2, C(CH.sub.3).sub.2C.sub.2H.sub.5, CH.sub.2C(CH.sub.3).sub.3, CH(C.sub.2H.sub.5).sub.2, C.sub.2H.sub.4CH(CH.sub.3).sub.2, C.sub.6H.sub.13, C.sub.7H.sub.15, cyclo-C.sub.3H.sub.5, cyclo-C.sub.4H.sub.7, cyclo-C.sub.5H.sub.9, cyclo-C.sub.6H.sub.11, PO.sub.3H.sub.2, PO.sub.3H.sup.?, PO.sub.3.sup.2?, NO.sub.2, C?CH, C?CCH.sub.3, CH.sub.2C?CH, C.sub.2H.sub.4C?CH, CH.sub.2C?CCH.sub.3, or R and R together forms one of the following groups: CH.sub.2CH.sub.2, COCH.sub.2, CH.sub.2CO, CH?CH, COCH?CH, CH?CHCO, COCH.sub.2CH.sub.2, CH.sub.2CH.sub.2CO, CH.sub.2COCH.sub.2 or CH.sub.2CH.sub.2CH.sub.2; X represents NH, NR, O, S, CH.sub.2, C.sub.2H.sub.4, C.sub.3H.sub.6, C.sub.4H.sub.8 or C.sub.5H.sub.10 or a C1 to C5 carbon chain, which can be substituted with one or more of the following residues F, Cl, OH, OCH.sub.3, OC.sub.2H.sub.5, NH.sub.2, NHCH.sub.3, NH(C.sub.2H.sub.5), N(CH.sub.3).sub.2, N(C.sub.2H.sub.5).sub.2, SH, NO.sub.2, PO.sub.3H.sub.2, PO.sub.3H.sup.?, PO.sub.3.sup.2?, CH.sub.3, C.sub.2H.sub.5, CH?CH.sub.2, C?CH, COOH, COOCH.sub.3, COOC.sub.2H.sub.5, COCH.sub.3, COC.sub.2H.sub.5, OCOCH.sub.3, OCOC.sub.2H.sub.5, CN, CF.sub.3, C.sub.2F.sub.5, OCF.sub.3, OC.sub.2F.sub.5; L is a hydrophilic substituent selected from the group consisting of NH.sub.2, OH, PO.sub.3H.sub.2, PO.sub.3H.sup.?, PO.sub.3.sup.2?, OPO.sub.3H.sub.2, OPO.sub.3H.sup.?, OPO.sub.3.sup.2?, COOH, COO.sup.?, CONH.sub.2, NH.sub.3.sup.+, NHCONH.sub.2, N(CH.sub.3).sub.3.sup.+, N(C.sub.2H.sub.5).sub.3.sup.+, N(C.sub.3H.sub.7).sub.3.sup.+, NH(CH.sub.3).sub.2.sup.+, NH(C.sub.2H.sub.5).sub.2.sup.+, NH(C.sub.3H.sub.7).sub.2.sup.+, NHCH.sub.3, NHC.sub.2H.sub.5, NHC.sub.3H.sub.7, NH.sub.2CH.sub.3.sup.+, NH.sub.2C.sub.2H.sub.5.sup.+, NH.sub.2C.sub.3H.sub.7.sup.+, SO.sub.3H, SO.sub.3.sup.?, SO.sub.2NH.sub.2, COCOOH, OCONH.sub.2, C(NH)NH.sub.2, NHC(NH)NH.sub.2, NHCSNH.sub.2, NHCOOH, ##STR00010##

2. The method according to claim 1, wherein mucilages include waxes, wax acids, lingins, hydroxy acids, mycolic acids, fatty acids with cyclic hydrocarbon structures including shikimic acid or 2-hydroxy-11-cyclo-heptyl undecanoic acid, mannosterylerythritol lipids, carotenes, carotenoids, chlorophylls, and their degradation products, phenols, phytosterols, beta-sitosterol, campesterol, sigmasterol, sterols, sinapine, squalene, phytoestrogens, steroids, saponins, glycolipids, glyceroglycolipids, glycerosphingolipids, rhamnolipids, sophrolipids, trehalose lipids, mannosterylerythritol lipids, polysaccharides, pectins, rhamnogalacturonans, polygalacturon acid ester, arabinans, galactans, arabinogalactans, pectic acids, amidopectines, phospholipids, phosphatidylinositol, phosphatids, phosphoinositol, long-chain or cyclic carbon compounds, fatty alcohols, hydroxy fatty acids, epoxy fatty acids, glycosides, lipoproteins, lignins, phytate, phytic acid, glucoinosilates, proteins, albumins, globulins, oleosins, vitamin A, vitamin B2, vitamin B5, vitamin B7, vitamin B9, vitamin B12, vitamin D, vitamin E, vitamin K, menaquinone, tannins, terpenoids, curcumanoides, xanthones, sugar compounds, amino acids, peptides, polypeptides, carbohydrates, and glucogen.

3. the method according to claim 1, wherein mucilages include waxes, wax acids, fatty alcohols, phenols, glycosides, lipoproteins, free sugars, lingines, phytate and phytic acid, hydroxy and epoxy fatty acids, mycolic acids, fatty acids with cyclic hydrocarbon structures including shikimic acid, or 2-hydroxy-11-cyclo-heptyl undecanoic acid, rhamnolipids, sophrolipids, trehalose lipids, mannosterylerythritol lipid, squalene, sterols, sinapines, vitamin A, vitamin B2, vitamin B5, vitamin B7, vitamin B9, vitamin B12, vitamin D, vitamin E and vitamin K.

4. The method according to claim 1, wherein in addition to the odorants and dyes, flavors are also removed.

5. The method according to claim 1, wherein the pre-purification is carried out in step b) by admixing water or an aqueous solution which has a pH in the range of 7.5 to 14.0, and then a phase separation is carried out.

6. The method according to claim 5, characterized in that the aqueous solution for pre-purification contains a base which is different from the substance of step c).

7. The method according to claim 1, wherein step b) is carried out at a maximum temperature of 45? C.

8. The method according to claim 1, wherein the concentration of the at least one substance in the aqueous phase in step c) is in a molar range of 0.001 to 0.8.

9. The method according to claim 1, wherein step d) is performed at a temperature of maximum 60? C.

10. The method according to claim 1, wherein step d) indicates the production of an intensive mixing.

11. The method according to claim 10, wherein the emulsions produced in step d) contain water droplets with diameters of <1 ?m.

12. The method according to claim 1, wherein the testing for the presence of mucilages in step a) is carried out by mixing an aqueous solution having a pH value in the range 8 to 13 with a sample of the lipid phase, wherein the volume ratio of the lipid phase to aqueous solution is 9:1 and wherein said test is positive when after mixing by shaking and phase separation, the formation of a layer has taken place.

13. The method according to claim 1, wherein before performing the method step c) a method step b1) determining the content of free fatty acids is carried out and performing process step b2) of adding one or more carboxylic acid(s) to the lipid phase and mixing is carried out until the content of the free carboxylic acids is at least 0.2 wt %.

14. The method according to claim 13, wherein the added carboxylic acid in step b2) is in the form of a nano-emulsion.

15. The method according to claim 1, wherein the lipid phase is a vegetable oil or animal fat for the food industry.

16. A lipid phase having a high storage stability obtainable by a method according to claim 1, wherein the lipid phase contains less than 0.2 wt % free fatty acids, less than 0.5 ppm of Na, K, Mg, Ca and/or Fe ions and/or less than 10% odorants based on the starting value of odorous substances.

17. Method according to claim 6, wherein the base which is different from the substance of step c) is selected from sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, and potassium bicarbonate.

Description

FIGURE DESCRIPTION

(1) FIG. 1: Shown are the results of an investigation for the presence of mucilages in camellia oil, raw and after refining procedures. The test was performed as in Example 1

(2) 1.) Crude oil with a content of phosphorus of 64 ppm and of free fatty acid of 1.2 wt %; after centrifugation there is a semi-solid mucilage phase which has a volume fraction of 10 vol %.

(3) 1.a) Sample of 1) after decantation of the oil phase.

(4) 2.) Sample after aqueous pre-purification step by means of citric acid; the content of phospholipids was 15 ppm and that of free fatty acid 1.0 wt %. After performance of the investigation for the presence of mucilages a semisolid mass with a volume fraction of 3.2 vol % is observable (test for the presence of mucilages positive).

(5) 3.) Sample after an additional aqueous pre-purification step by means of a sodium carbonate solution; the phosphorus content was 8 ppm and that of free fatty acids 0.45 wt %. The investigation for the presence of mucilages exhibits a thin mucilage layer that has a volume fraction of 0.9 vol % (test for the presence of mucilages negative).

EXAMPLES

(6) Measurement Methods

(7) The following test methods were used in the embodiments as described below:

(8) The content of phosphorus, calcium, magnesium, and iron in lipid phases was determined by ICP OES (iCAP 7400, Thermo-Fisher, Scientific, Germany). Values are given in ppm (or mg/kg).

(9) The content of free fatty acids in a lipid phase was determined by means of a methanolic KOH titration with a TitroLine 7000 titrator (SI Analytics, Germany). Values are given in weight% (g/100 g).

(10) Determination of chlorophyll concentrations in oil samples was performed, unless otherwise stated, from samples poured in 10 mm cuvettes without further dilution with a UV-visible spectrometer (UV-1601, Shimadzu, Japan) at 630, 670, and 710 nm. The calculation of the total amount of chlorophylls was performed according to the AOCS method Cc formula of 13e-92.

(11) Quantification of turbidity (turbidimetry) of oil phases or reaction mixtures was performed using a scattered light detector, wherein the re-entry of a scattered beam at an angle of 90? is determined by a measuring probe, which was immersed in a sample volume of 10 ml (InPro 8200-measuring sensor, M800-1 transmitter, Mettler Toledo, Germany). The measuring range is 5-4000 FTU. Measurements were made in duplicate for each sample.

(12) Determinations of droplet or particle sizes were made by the use of a noninvasive laser light backscatter analysis (DLS) (Zetasizer Nano S, Malvern, UK). To this end, 2 ml of a liquid to be analyzed was poured into a measuring cuvette and placed in the measuring cell. The analysis on particles or phase boundaries forming droplets was run automatically. The measuring range covered diameters between 10 ?m and 0.3 nm.

(13) Determination of secondary oxidation products in a lipid phase was performed with a p-anisidine reaction, which was quantified photometrically. A 20 ?l aliquot of the oil to be tested was added to a cuvette that already contained the test reagent and placed immediately thereafter in the measuring chamber of an automatic analyzer (FoodLab, Italy). The measuring range was between 0.5 and 100. Each sample was analyzed twice.

(14) The analysis of 3-MCPD was carried out by mass spectroscopy. Sample preparation and analysis was performed as described in: Zhou Y, Wu Z, Li C. Coupling neutral desorption sampling to dielectric barrier discharge ionization mass spectrometry for direct oil analysis. Anal. Methods, 2014, 6: 1538-1544.

(15) The concentration of benzo-a-pyrene was performed according to the DGF method III 17a.

(16) The pH was determined with a glass capillary electrode (Blue Line, ProLab 2000, SI Analytics, Germany).

(17) All solutions with compounds containing at least one amidino group or at least one guanidino group were prepared from a low-ion or ion-free water phase.

(18) All tests were carried out under atmospheric pressure (101.3 Pa) and an ambient temperature of 25? C., unless otherwise specified.

Example 1

(19) Canola oil, which was obtained by means of a screw press as a yellow-greenish slightly turbid raw oil, was analyzed for phosphorus content (ICP-EOS, iCAP 7400, Thermo-Fisher, Scientific, Germany). Further, an investigation for the presence of mucilages was performed by adding 1 ml of a 5 wt % sodium carbonate solution (pH 12.5) to 9 ml of the raw oil. The sample which was in a centrifuge glass was agitated (vortexed at 3,000 rpm) for 3 minutes. Subsequently, the sample was centrifuged at 3,000 rpm for 5 minutes. A semisolid emulsion layer that was 3 mm thick (corresponding to a volume of 0.3 ml or 3.0 vol %, respectively) located at of the water-oil phase boundary was observed. The acid number of the oil was determined by potentiometric titration (Titroline 7000 SI Analytiks, Germany) by means of an alcoholic KOH solution. The oil has a strong smell and a slight bitter taste.

(20) After 200 kg of the raw oil was heated to 60? C., and a 75 vol % phosphoric acid solution was added in a volume ratio of 0.4 vol %. Then the liquids were homogenized with a homogenizer (Fluco MS 4, Fluid Kotthoff, Germany) at a rotational speed of 1,000 rpm for 30 minutes. The homogenized mixture was allowed to stand for 30 minutes at 65? C. Then phase separation with a plate separator (OSD 1,000, MKR, Germany) at a throughput volume of 100 1/h and a rotational speed of 10,000 rpm was performed. An investigation for the presence of mucilages was performed from a sample which showed an emulsion layer of 0.2 ml or 2.0 vol %, respectively. Then 200 ml of a 0.5 M arginine solution was added to 10 kg of the prepurified oil and mixed by using a homogenizer (Fluco MS2, Fluid Kotthoff, Germany) (3000 rpm for 1 minute). There was immediate formation of a highly viscous emulsion, which made further mixing impossible. No phase separation of the high viscous emulsion could be achieved by centrifugation (4,500 rpm/20 minutes). In another investigation the same arginine solution with an identical amount was admixed to 10 kg of the acid-treated oil by continuously mixing the liquids with a propeller mixer (500 rpm). This resulted in a highly viscous emulsion which was just still flowable. Phase separation performed by centrifugation (3,800 rpm/10 minutes) remained incomplete. The remaining acidic precleaned oil was subjected to a further pre-purification step, which was performed with a sodium hydroxide solution (1 N, 3 vol %). For this purpose the two liquids were stirred first and then intensively mixed with a homogenizer (Fluco MS 4, Fluid Kotthoff, Germany) for 10 minutes at 1,000 rpm. Thereafter phase separation by means of the above-mentioned separator was achieved. Then, the phosphorus content and the acid number were determined. In investigation for the presence of mucilages there was only a weakly discernible skinning at the water-oil phase boundary (volume <0.1 ml corresponding to <1.0 vol %). Each of 10 kg of the obtained slightly turbid oil were refined according to the following schemes: admixing the aqueous arginine solution by means of: A) stirring with a propeller mixer at 500 rpm for 30 minutes at 35? C.; B) homogenizing with the above homogenizer (Fluco MS2, fluid Kotthoff, Germany) (1000 rpm, for 5 minutes at 25? C.), using solutions with an arginine concentration of 1) 0.3 mol/l, or 2) 0.6 mol/l, and by using a volume addition of a) 1 vol %, or b) 3 vol %, or c) 5 vol %. In one investigation, the precleaned oil was treated again with a sodium hydroxide solution (1 N, 3 vol %) admixed with a propeller mixer (500 rpm) for 30 minutes (C.1) or with the homogenizer, as described previously (C.2). Then phase separation was performed with the separator as described above.

(21) Determination of the contents of phosphorus, sodium, potassium, calcium, and iron was carried out by means of ICP-OES (ICAP 7400, Thermo-Fisher Scientific, Germany). Determination of chlorophyll concentrations was carried out according to the methods specified under the measurement methods section after the vacuum drying of the oils. Measurements on the color spectra were performed by the Lovibond color scale test method according to the ISO 15305 method with Lovibond Colour Scan (Tintometer Ltd., Amesbury, UK, 5? cell).

(22) Results (summarized in Tables 1a and 1b):

(23) After a pre-purification process using a solution of phosphorus acid, the oils still had a greenish color and a musty smell. Admixture of an arginine solution by means of an intensive mixer to the acidic precleaned oil led to formation of stable emulsions that could not be separated into separate phases, independently from the dosing technique used. Although admixture of arginine solution by stirring was possible, the emulsive mixture was highly viscous, so that phase separation was incomplete; thus no further refining attempts were made here. After a second pre-purification process using an alkaline solution, the investigation for the presence of mucilages was negative and admixture of an arginine solution was possible by all mixing modalities. The resulting water-in-oil emulsions differed clearly in their appearance: after admixture with a stirrer, the reaction mixture had an oil-like character and a yellow-greenish color, with a moderate to severe turbidity; after admixture using an intensive mixing process, the reaction mixture had a milky character with a whitish to light yellow color and considerable turbidity. Phase separation with a separator was possible in all; the water phases obtained after performance of the admixture by stirring were significantly turbid with a yellowish hue and those obtained after an intensive mixing process were turbid and greenish. The oils differed after phase separation, in which the oil was almost clear after mixing with a stirrer, and the oils obtained after an intensive mixing process were markedly turbid. In order to obtain comparability between the refined oils and to allow feasibility of the analysis, the oils were dried first by a vacuum dryer (VC-130SC, Cik, Germany) at a temperature of 55? C. over a period of 120 minutes and under a pressure of 0.01 Pa. Then the oil obtained after an intensive mixing process had a brilliant appearance in contrast to the oil obtained after mixing with a stirrer, which still had a slight haze. Already visible with the eye was then a color difference of the obtained oil phases: the oil color after an intensive mixing procedure was yellowish and yellowish to slightly greenish after mixing with a stirrer. The color of both refined oils differed clearly from that of the oil obtained after acid pre-purification. Obvious was also the change in the odor in the refined oils. In oils obtained after mixing with a stirrer there was a faint plant smell, after refinement with an intensive mixing of the arginine solution, the oil was virtually odorless. While the oil after mixing with a stirrer had a nutty taste and a discreet bitter aftertaste, the oil obtained after an intensive mixing of the arginine solutions had no aftertaste. Oils which were treated for a second time with sodium hydroxide had a slightly greenish appearance and a distinct plant smell and a soapy and slightly bitter taste, which persisted after both, a mixture of the solution with a stirrer or mixing with an intensive mixing process. An analysis of the greenish water phase obtained by phase separation of the reaction mixture after performance of an intensive mixing process with the arginine solution which had an intense odor (plant smell) revealed the presence of chlorophylls.

(24) TABLE-US-00001 TABLE 1a Phos- Magne- Refining phorus FFA sium Potassium Calcium Iron step [mg/kg] [wt %] [mg/kg] [mg/kg] [mg/kg] [mg/kg] Raw 664 1.8 56 72 164 2.5 material after 32 2.0 29 8.8 32 1.2 H.sub.3PO.sub.4 after 15 0-3 5.2 5.1 10 1.3 NaOH A.1.a 8 0.18 12 1.8 1.7 0.9 A.1.b 6 0.12 1.3 1.3 2.0 0.8 A.1.c 5 0.11 1.0 1.4 1.5 0.8 A.2.a 7 0.08 0.1 0.1 0.8 0.7 A.2.b 4 0.09 0.15 0.1 1.0 0.8 A.2.c 3 0.06 0.1 0.08 0.5 0.6 B.1.a 5 0.07 004 0.05 0.023 0.2 B.1.b 2 0.05 <0.02 <0.02 <0.02 0.1 B.1.c 2 0.03 <0.02 <0.02 <0.02 <0.1 B.2.a 0.9 0.03 <0.02 <0.02 <0.0 <0.02 B.2.b 0.6 0.01 <0.02 <0.02 <0.02 <0.02 B.2.c 0.5 0.01 <0.02 <0.02 <0.02 <0.02 C.1 12 0.24 5.1 5.2 10 1.3 C.2 11 0.20 5.2 5.1 11 1.3

(25) TABLE-US-00002 TABLE 1b Lovibond color scale values Refining step Lovibond-red Lovibond-yellow Raw material 12.3 55 after H.sub.3PO.sub.4 8.9 45 after NaOH 9.2 42 A.1.a 7.5 38 A.1.b 7.4 37 A.1.c 7.6 39 A.2.a 7 40 A.2.b 7.2 36 A.2.c 6.9 37 B.1.a 3.6 28 B.1.b 3.2 24 B.1.c 3 25 B.2.a 3.1 26 B.2.b 3 23 B.2.c 3.1 24 C.1 9.3 41 C.2 9.1 42

Example 2

(26) Investigation on the Use of Nano-Emulsions for Oil Refining.

(27) For this investigation jatropha oil was used which contains naturally very low concentrations of green dyes, but has an unpleasant odor and due to a high proportion of mucilages it is not possible to refine it by aqueous refining methods. Here the smell is intense, pungent and has an unpleasant species-specific character. The concentration of phosphorus was 78 ppm (mg/kg) and the acid number was 1.3 wt % (analytical method according to Example 1). The investigation for the presence of mucilages was carried out as in Example 1, using a water:oil ratio of 1:10. There was an emulsion layer of 0.7 ml (corresponding to 7.0 vol %) at the oil-water interface with only a small volume of free water. Jatropha raw oil (10 kg) was precleaned by aqueous extraction with a solution of sodium carbonate (concentration: 10 wt %, volume admixed: 3 vol %); mixing was performed with a propeller mixer (500 rpm for 30 minutes). Phase separation was performed by means of a beaker centrifuge (3,800 rpm/5 minutes). The investigation for the presence of mucilages showed then a semisolid emulsion layer that had a volume fraction of 3.0 vol %. Therefore, the aqueous refining procedure by means of a sodium carbonate solution (concentration: 20 wt %, volume admixed: 3 vol %) was performed using an intensive mixing process with a homogenizer (Fluco MS2, Fluid Kotthoff, Germany) (1,000 rpm, for 5 minutes at 25? C). Then, the repeated investigation for the presence of mucilages showed only a thin layer at the water-oil phase boundary (<1.0 vol %). The oil had an intense species-specific odor. The refined oils had the following key characteristics: phosphorus 6 ppm (mg/kg), acid number of 0.25 wt %, calcium 0.01 ppm (mg/kg), iron 0.01 ppm (mg/kg). The oil was subjected to a nanoemulsifying aqueous extraction by means of a 0.4 molar arginine solution; to each 5 liters of prepurified Jatropha oil, 100 ml of arginine solution was added and (M 1) intensive mixing was performed with an Ultraturrax T50 (5,000 rpm for 2 minutes at 25? C.) or (M 2) mixing was performed with a propeller mixer (500 rpm for 60 minutes at 25? C.). Then phase separation was obtained by means of a beaker centrifuge (3,800 rpm/5 minutes). The refined jatropha oil (M 2) had a distinct species-specific odor, while the purified oil obtained by intensive mixing (M 1) only had a very faint odor. The key characteristics amounted (M1/M 2): phosphorus 2/0.5 ppm (mg/kg), acid number 0.03/0.01 wt %, calcium 0.01/0.01 ppm (mg/kg), iron 0.02/<0.02 ppm (mg/kg).

(28) Chlorophyll A (60 mg, Sigma Aldrich, Germany), which was first dissolved in acetone, was admixed to 2 kg of the refined oil from M 1 for 10 minutes. The clear oil then had a distinct green color. The solvent was removed by vacuum extraction, thus, resulting in the oil phase M 3.

(29) Nano-emulsions were prepared by adding to 100 ml of 0.5 M arginine stock solution a) 3.2 ml of oleic acid, b) 2.4 ml palmetoleinic acid, and c) 1.9 ml of erucic acid at 40? C., which were mixed (12 hours) until complete dissolution with a stirrer, then transparent nano-emulsions formed. To each 100 ml of the oil from M 3 2 ml was added of: the nano-emulsions a)-c) as well as 2 ml ion-free water (d) or an arginine solution (0.5 molar) (e). The samples were homogenized using an Ultraturrax T18 with 18,000 rpm for 4 minutes at 25? C. Phase separation was carried out using a beaker centrifuge at 5,000 rpm for 8 minutes at room temperature. Other approaches were carried out with each 100 ml of the oil M 3 to which 3 g of each bleaching clays Filtrol-105 (f), or CLARION 470 (g) were added and mixed at 80? C. for 60 minutes with a magnetic stirrer. All oil samples were centrifuged immediately after the end of the investigation (5,000 rpm for 8 minutes) and then subjected to drying, which was carried out according to example 1. Analysis of the key oil characteristics was performed as well as determination of the chlorophyll concentrations (see measurement methods). Further, in all experiments, two samples were taken for determining the anisidine values and if not already done, subjected to vacuum drying.

(30) One of 2 additional samples (10 ml) was frozen (t0), the second sample was stored under exclusion of air for 4 months (t120) at room temperature and in daylight. At the end of this investigation, samples t0 were thawed and analyzed together with the stored samples in one run according to the procedure described in measurement methods.

(31) TABLE-US-00003 TABLE 2 Lovibond Investigation Chlorophyll red (R)/ no. ppm (mg/kg) yellow (Y) Anisidine t0 Anisidine t120 Raw oil 0.24 R 12.8/Y 29 4.2 38.4 M 1 0.03 R 3.2/Y 6.1 0.5 3.9 M 2 0.08 R 4.7/Y 9.5 0.9 7.3 M 3 32.4 R 5.2/Y 56.2 0.7 44.6 M 3a) 0.04 R 3.2/Y 5.8 0.5 1.2 M 3b) 0.12 R 3.3/Y 8.2 0.5 2.1 M 3c) 0.03 R 3.3/Y 6.0 0.5 1.1 M 3d) 32.1 R5.3/Y56.5 0.9 45.1 M 3e) 0.82 R3.9/Y16.2 0.5 8.2 M 3f) 0.73 R3.0/Y 15.1 0.9 16.9 M 3g) 1.03 R3.7/Y16.2 1.1 17.3

(32) Results:

(33) The investigated oil had a significant amount of mucilages despite a low content of phosphorus-containing compounds. After a repeated alkaline pre-purification process, the investigation for the presence of mucilages was negative and an intensive mixing process with an arginine solution was possible. With the use of the intensive mixing process, a more efficient reduction of phosphorus-containing compounds, earth alkali metals, and metal ions as well as of the content of acid groups and of chlorophylls was achieved as compared with a mixing process with a stirrer. When chlorophyll was admixed to the refined oil, which have been obtained by means of an intensive mixing procedure and which exhibited a content of acidic groups that was below the predetermined process specification, only partial removal of the chlorophyll content could be achieved by an intensive mixing process using an arginine solution; however, the reduction of the chlorophyll content and the bleaching effect achieved corresponded to those which have been achieved by bleaching earths.

(34) Refinement of the oil M 3 by means of nano-emulsions that was admixed using an intensive mixing process however resulted in an optimal extraction of chlorophyll and had an optimal bleaching result; the water phases were green with a slight haze. An investigation of the water phase obtained showed the presence of chlorophyll.

(35) In a comparative investigation with pure water, there was a spontaneous separation of the water and oil phases; both were unchanged to those measured at the start. The oil which was treated with a nano-emulsion consisting of arginine and palmetoleinic acid, only had a minimal shade of green, while the color of the other oils treated with a nano-emulsion were indistinguishable from the oil used originally, i.e., before addition of chlorophyll.

(36) The crude oil exhibited a great amount of secondary oxidation products. A considerable reduction of the oxidation products was achieved in all refining processes investigated; however, the lowest contents were present after an intensive mixing process with an arginine solution or a nano-emulsion in oils that have received chlorophyll. After 4 months, there was a substantial increase in the content of secondary oxidation products in the raw oil and in the oil, in which chlorophyll had been added. As compared to oil that had been refined by admixture of the arginine solution with a stirrer, the oil refined with an intensive mixing process of the arginine solution had better storage stability.

(37) Oils, in which a substantially complete depletion of chlorophyll has been achieved by intensive mixing with nano-emulsions, exhibited the best storage stability. In oils treated with bleaching earths, there was deterioration in the storage stability despite of a reduction of the chlorophyll content, which was comparable to the one obtained by a refining with an arginine solution.

Example 3

(38) Cold pressed rapeseed oil with the key parameters: phosphorus content 4.1 ppm (mg/kg), calcium 28 ppm (mg/kg), iron 2.5 ppm (mg/kg), free fatty acids 1.1 wt %, chlorophyll content 6.8 ppm (mg/kg), that had a clear appearance and a slightly green-yellowish color, and a mustard-like odor as well as an intensely rancid and bitter taste was used for the following investigation. The investigation for the presence of mucilages was negative (<0.1 ml/<1.0 vol %, for protocol see example 1). To each of 1000 ml oil, 30 ml of 0.5 M arginine solution was added. Mixing was carried out with A) a propeller mixer at 200 rpm for 30 minutes, B) with a propeller mixer at 800 rpm for 15 minutes, and C) with an Ultraturrax T18 at 24,000 rpm for 5 minutes. Then centrifugation with a beaker centrifuge was performed (5,000 rpm for 10 minutes). Oil analyses were carried out as described in Examples 1 and 2. In each case, 2 samples (20 ml) of the raw oil (RO) and the refined oils A) and C) were taken, from which one sample was frozen directly (t0) and the other was left standing in an open vessel for 30 days, at room temperature and daylight (t30). For analysis of secondary oxidation products, the samples t0 were thawed and analyzed along with the samples t30 (analytics according to measurement methods). The viscosity of the raw oil and the emulsions obtained after mixing with the aqueous phase was determined by a vibrational viscometer (Visco Lite d15, PCE Instruments, Germany) which was attached to a tripod and immersed in the upper layer of the process liquid. In investigation C) a sample of the reactive mixture was taken 60 seconds after start of homogenization and the viscosity was immediately determined herein. All measurements were performed at the same temperature (28? C.).

(39) Results:

(40) In the samples obtained by process A) and C), phase separation by centrifugation was possible. The sample, which was obtained by the process B) was highly viscous; here phase separation was insufficient, so that further investigations were not performed. The crude oil had a viscosity of 152 mPa.Math.s, that of emulsions from process A) was 368 mPa.Math.s after 5 minutes of stirring and that of C) was 3520 mPa.Math.s after 60 seconds and 26 mPa.Math.s after 5 minutes. The oil phase of the samples A and C were clear to brilliant. While the oil from A) still had a slight green tint, the oil from C) was pale yellowish. The resultant oils had contents of phosphorus (A or C) of 3.6 and 0.8 ppm (mg/kg), calcium of 1.3 and 0.02 ppm (mg/kg), iron of 0.9 and <0.01 mg/kg and free fatty acids of 0.08 and 0.04 wt %, respectively. The chlorophyll content was 0.96 ppm (mg/kg) for oil A) and was 0.02 ppm (mg/kg) for oil C). The sensory test revealed a discrete plant odor in sample of oil A, while oil C was virtually odorless. The taste of oil A) was much less intense than that of the raw oil while having a slightly bitter aftertaste. The oil from experiment C had a slightly nutty flavor character with a pleasant mouth feeling, and no aftertaste. In both separated aqueous extraction phases chlorophyll and phospholipids could be detected. Further, the aqueous phase had an intense musty and plant odor. The anisidine value for the crude oil was 3.7 at baseline and 38.4 after 30 days. By refining, secondary oxidation products were reduced more significantly by the intensive mixing process with arginine, compared to mixing an arginine solution with a stirrer (anisidine value after refining in C) was 0.6 vs. 0.9 in A)). During the storage period, more secondary oxidation products developed in oil A) compared to oil C) (12.6 vs 3.1).

Example 4

(41) Investigations on the Deodorization Effectiveness of an Aqueous Extraction by Means of an Arginine Solution.

(42) For the investigation oils from rapeseed (RSO), sesame (SEO), and sunflower seeds (SSO), which had been already stored for 2-3 years and exhibited a significant rancid odor and taste, were selected. The sunflower and rapeseed oil had also a greenish appearance. The key oil parameters were as follows, for RSO: phosphor 4 ppm (mg/kg), calcium 23 ppm (mg/kg), magnesium 3 ppm (mg/kg), iron 1 ppm (mg/kg), acid value 1.2 wt %, chlorophyll 12.4 ppm (mg/kg); for SEO: phosphorus 6 ppm (mg/kg), calcium 67 ppm (mg/kg), magnesium 12 ppm (mg/kg), iron 4 ppm (mg/kg), acid value 0.8 wt %, chlorophyll 8.2 ppm (mg/kg), and for SSO: phosphorus 24 ppm (mg/kg), calcium 64 ppm (mg/kg), magnesium 13 ppm (mg/kg), iron 4 ppm (mg/kg), acid number 0.8 wt %, chlorophyll 4.4 ppm (mg/kg). The determination of the oil characteristics was performed as described in Example 1, chlorophyll concentration was determined as described under measurement methods. The investigation for the presence of mucilages (conduction according to Example 1) showed a solid emulsion layer of 0.5 ml or 5.2 vol % at the oil-water interface with minimal amount of free water volume in SSO, a semisolid emulsion layer of 0.4 ml or 4.1 vol % in SEO with a yellowish almost clear water phase, and no emulsion layer (<0.1 ml or <1.0 vol %) in RSO, wherein the aqueous phase was greenish and turbid. For each investigation 6 liters of crude oil were used.

(43) Pre-purification of the SSO was performed with citric acid (25 wt %, volume addition 0.3 vol %), the mixture was homogenized with an Ultraturrax T25 (20,000 rpm) for 3 minutes and centrifugal phase separation was carried out after a waiting period of 15 minutes at 3,800 rpm for 5 minutes. Then, the investigation for the presence of mucilages showed a semisolid emulsion layer of 0.3 ml or 3.3 vol % on a clear slightly yellow water phase. Therefore, a further pre-purification was performed with an aqueous solution of sodium metasilicate anhydrate (10 wt %), which was completely dissolved, admixed using a volume ratio of 3 vol % and by performing an intensive mixing procedure with the Ultraturrax (20,000 rpm for 3 minutes); subsequently the reaction mixture was centrifuged (3,800 rpm for 5 minutes). The investigation for the presence of mucilages then showed only a thin film at the phase boundary (<1.0 vol %). The initially present pungent odor of the oil was reduced significantly; however, a strong rancid odor persisted.

(44) An aqueous solution with completely dissolved sodium bihydogencarbonate (20 wt %) was added to the SEO (added volume 4 vol %) and mixed (20,000 rpm for 5 minutes) by means of an intensive mixing process with the aforementioned Ultraturrax and then phase separation was obtained by centrifugation (3,800 rpm for 5 minutes). In the investigation for the presence of mucilages, there was still a semisolid emulsion layer of 0.3 ml or 3.4 vol %. Therefore, the previously performed aqueous refining stage was repeated. Then, investigation for the presence of mucilages showed only a membrane-like structure at the phase boundary (<1.0 vol %). The smell of the oil was virtually unchanged compared to the raw material.

(45) In RSO, the investigation for the presence of mucilages showed virtually no emulsion layer (<0.1 ml or <1.0 vol %) and therefore no pre-purification was performed.

(46) The precleaned oils had the following key characteristics, in SEO: phosphorus 3 ppm (mg/kg), calcium 12 ppm (mg/kg), magnesium 2 ppm (mg/kg), iron 0.5 mg/kg, acid number 0.3 wt %, chlorophyll 6.2 mg/kg; in SSO: phosphorus 6 ppm (mg/kg), calcium 14 ppm (mg/kg), magnesium 2 ppm (mg/kg), iron 1.5 ppm (mg/kg), acid number of 0.35 wt %, chlorophyll 3.9 ppm (mg/kg).

(47) Then, 3 liters each of precleaned SSO and SEO and the raw rapeseed oil were mixed with an arginine solution (0.5 molar, added volume 3 vol %) by an intensive mixing procedure with the Ultraturrax (20,000 rpm, 6 minutes). Subsequently, phase separation was obtained with a separator (3,800 rpm for 5 minutes). The oils obtained had the following key characteristic: for RSO phosphorus 2 ppm (mg/kg), calcium 0.3 ppm (mg/kg), magnesium 0.08 ppm (mg/kg), iron 0.01 ppm (mg/kg), acid number 0.08 wt %, chlorophyll 0.08 ppm (mg/kg); for SEO: phosphorus 1 ppm (mg/kg), calcium 0.8 ppm (mg/kg), magnesium 0.05 ppm (mg/kg), iron 0.01 ppm (mg/kg), acid number 0.05 wt %, chlorophyll 0.02 ppm (mg/kg) and for SSO: phosphorus 2 ppm (mg/kg), calcium 0.8 ppm (mg/kg), magnesium 0.04 ppm (mg/kg), iron 0.01 ppm (mg/kg), acid number of 0.03 wt %, chlorophyll 0.01 ppm (mg/kg);

(48) A sensory quality testing of the refined oils was performed in which the sensory characteristics were compared with corresponding commercially available premium oils (comp) in which a classical refining including bleaching and deodorization have been carried out.

(49) The oils were examined by 4 trained tasters who performed blinded evaluation of taste and odor; tests were performed in triplicate. The following organoleptic characteristics were evaluated:

(50) Positive attributes: seed-like and nuttiness; negative attributes: rancid, straw-like, woody, roasted, burned, bitter, astringent, fusty, musty or fishy. The intensity of each sensory characteristic was judged and scaled by a level of intensity from 0 (none) to 10 (very intense).

(51) The tastings were performed on oils at a temperature of 28? C. that were served in a tinted glass, sealed with a watch glass.

(52) The aqueous phases obtained after nano-emulsifying aqueous extraction by means of an arginine solution had a greenish milky appearance and a musty to pungent plant smell. Quantitative analyses for chlorophyll, phospholipids, and glycolipids were performed from the water phases.

(53) The results are listed in Table 4:

(54) TABLE-US-00004 TABLE 4 RPO - RPO- RPO- SEO- SEO- SEO- SSO- SSO- SSO- raw refined deodorized raw refined deodorised raw refined deodorized Seed-like 3 5 3 6 5 4 4 6 3 Nutty 1 3 2 3 3 1 2 3 1 fruity 0 0 0 0 0 0 0 0 0 rancid 7 0 0 6 0 0 4 0 0 woody 3 0 0 0 0 0 3 0 0 fusty 0 0 0 0 0 0 3 0 0 musty 5 0 0 4 0 0 3 0 0 astringent 4 0 0 3 0 0 3 0 0 bitter 2 0 0 4 0 0 0 0 0 Sum of 21 0 0 17 0 0 16 0 0 off-flavors

(55) Results:

(56) The studied vegetable oils had a significant content of off-flavors and unpleasant smells due to the extraction conditions or aging. In one of the oils, the pre-purification step had to be repeated because of a positive result of the investigation for the presence of mucilages, indicating an unacceptable content of mucilages after the first pre-purification step. Finally, all oils were refined by means of an intensive mixing process with an aqueous arginine solution after wathing with the process indicators. Oil tastings revealed that off-odors or off-flavors have been completely removed; the sensory quality corresponded to a respective commercially available oil produced by a refining process according to prior art, which included the processes of bleaching and deodorization. Furthermore, oils refined with the nano-emulsifying refining procedure exhibited a stronger intensity of positive sensory characteristics as compared to comparable premium oils. Furthermore, a considerable reduction in the chlorophyll content of the aqueous refined oils could be documented. In the aqueous phases chlorophyll, phospholipids, and glycolipids were detected. Further, odorants and off-flavors, having a very intense plant smell, with a musty, beany, and pungent character were present. A brief taste test from a drop of the aqueous phase (tasting unreasonable) gave evidence of astringent and bitter flavors.

Example 5

(57) Investigations on the Bleaching of Oils by an Aqueous Extraction by Means of an Arginine Solution.

(58) Investigations were performed on soybean oil (SO) obtained by hexane extraction, rapeseed oil (RO) from a winter crop, grape seed oil (GSO), and camelina oil (CO). All oils were clear; the SO had a straw yellow to light brown color, the RO an olive-green tint, the GSO an intense green color and the CO an intense yellow color with a discreet shade of green. The experiments were performed on 5 liters of the raw oils. Oil characteristics were determined according to Example 1; determinations of chlorophyll were performed with a Lovibond PFX1-995 (Tintometer, UK).

(59) The oils had the following key oil parameters, for SO: phosphorus 380 ppm (mg/kg), calcium 84 ppm (mg/kg), magnesium 56 ppm (mg/kg), iron 17 ppm (mg/kg), acid number 1.4 wt %; for RO: phosphorus 8.3 ppm (mg/kg), calcium 37 ppm (mg/kg), magnesium 8 ppm (mg/kg), iron 4 ppm (mg/kg), acid value 0.6 wt %, for GSO: phosphorus 54 ppm (mg/kg), calcium 15 ppm (mg/kg), magnesium 8 ppm (mg/kg), iron 3 ppm (mg/kg), acid number 0.8 wt % and for CO: phosphorus 28 ppm (mg/kg), calcium 33 ppm (mg/kg), magnesium 12 ppm (mg/kg), iron 2 ppm (mg/kg), acid number 0.5 wt %.

(60) Due to a phosphorus content of >15 ppm (mg/kg) SO, GSO, and CO were subjected to a refining with phosphoric acid (85 vol %, volume addition 0.3 vol %), admixed by an intensive mixing process with a homogenizer (Ultraturrax T50, 8,000 rpm, 3 minutes). Phase separation was carried out after 30 minutes by means of a beaker centrifuge (4,000 rpm, 5 minutes).

(61) The investigation for the presence of mucilages (as described in Example 1) was then performed in all the oils (precleaned or raw, respectively) showing semisolid emulsion layers with a volume/volume fraction in SO: 0.5 ml or 5.5 vol %; in RO: 0.3 ml or 3.3 vol %; in GSO: 0.6 ml or 6.4vo1%; in CO: 0.5 ml or 5.0 vol %. Therefore, an aqueous pre-purification step was performed in all of the oils by means of a solution of sodium carbonate pentahydrate (20 wt %, volume addition 5 vol %), admixed by an intensive mixing process with the above stated homogenizer for 5 minutes at 10,000 rpm. Phase separation was carried out thereafter as previously described. The investigation for the presence of mucilages was again positive for the refined GSO (emulsion layer of 2.0 vol %); therefore, the refining step was repeated in this oil. Subsequently, the investigation for the presence of mucilages was negative in all oils (emulsion layers with a volume/volume fraction <0.1 ml/<1.0 vol %). Then the content of phosphorus was analyzed, which was 14 ppm (mg/kg) in SO, 5 ppm (mg/kg) in RO, 9 ppm (mg/kg) in GSO, and 4 ppm (mg/kg) in CO. Half of the obtained oil phases were refined with an arginine solution (0.3 molar, volume addition 5 vol %) admixed by an intensive mixing process with the above stated homogenizer for 5 minutes (10,000 rpm). Phase separation was carried out as previously described.

(62) The resulting oil phase had the following contents in SO: phosphorus 1.3 ppm (mg/kg), calcium 0.08 ppm (mg/kg), magnesium 0.03 ppm (mg/kg), iron 0.01 ppm (mg/kg), acid number of 0.08 wt %; in RO: phosphorus 0.8 ppm (mg/kg), calcium <0.02 ppm (mg/kg), magnesium <0.02 ppm (mg/kg), iron <0.02 ppm (mg/kg), acid number 0.02 wt %, in GSO: phosphorus 3 ppm (mg/kg), calcium 0.08 ppm (mg/kg), magnesium <0.02 ppm (mg/kg), iron <0.02 ppm (mg/kg), acid number 0.18 wt % and in CO: phosphorus 1.2 ppm (mg/kg), calcium 0.06 ppm (mg/kg), magnesium <0.02 ppm (mg/kg) iron <0.02 ppm (mg/kg), acid number of 0.02 wt %.

(63) Each of the second halves of the pre-purified oils was divided onto 2 beakers. To each of which, one of the bleaching clays (bleaching earth 1: Tonsil Optimum 210 FF amount added 2 wt %; bleaching earth 2: Tonsil Supreme 118 FF, amount added 2 wt %) was added and stirred at a temperature of 100? C. and a vacuum of 1000 Pa for 60 minutes. Subsequently, solids were removed by centrifugation, as described above, the oils were dried according to Example 1.

(64) Determination of the chlorophyll A content and of the Lovibond red (R) and yellow (Y) color scale values was done in all raw oils, the oils obtained after pre-purification steps, and after the aqueous extraction by means of arginine or bleaching earths treatment, respectively; results are shown in Table 5.1 and Table 5.2. In each of the raw oils, and the oils refined with the arginine solution or with bleaching earths, 2 samples were taken, which were subjected to vacuum drying according to Example 1, of which one of the samples was frozen (t0), the other was allowed to stand at room temperature and day light exposure under exclusion of air for 120 days (t120). Subsequently, the thawed samples tO and the samples t120 were examined for secondary oxidation products (experimental procedure according to measurement methods) (Ansisdine test results are listed in Table 5.3) and for tocopherol content. Furthermore sensory tastings were carried out according to Example 4 and the results are summarized in Table 5.3 (calculated as described in Example 4).

(65) TABLE-US-00005 TABLE 5.1 Chlorophyll content (mg/kg) Raw After pre- Bleaching Bleaching oil purification After refining earth1 earth 2 SO 58 4.9 0.02 0.03 0.02 RO 72 7.2 0.06 0.05 0.07 GSO 98 10.3 0.01 0.02 0.02 CO 67 5.8 0.01 0.01 0.01

(66) TABLE-US-00006 TABLE 5.2 LOVIBOND After pre- Bleaching Bleaching Raw oil purification After refining earth 1 earth 2 SO R18.4/Y68 R15.3/Y48.8 R 2.2/Y 6.3 R 1.8/Y 5.5 R2.3/Y5.8 RO R10.8/67.8 R 11.2 Y 43.1 R 6.2 Y 8.4 R 5.8/Y 9.5 R 6.0/Y 8.5 GSO R8.5/Y 70 R 9.2/Y 56.4 R 6/Y 26.3 R 4/Y 27.5 R5/Y25.2 CO R24.3/Y70 R12.2/Y51.6 R 9/Y 9.3 R10/Y 10.2 R9/Y 9.1

(67) TABLE-US-00007 TABLE 5.3 Anisidine Off-flavor SO RO GSO CO SO RO GSO CO Raw oil t0 4.2 3.8 2.1 2.5 16 14 12 19 Raw oil 27.8 26.6 17.1 36.4 21 26 19 28 120 NV t0 1.4 1 2.1 1.8 12 15 16 14 NV t120 22.1 18.7 15.5 28.1 22 25 20 12 NA t0 0.5 0.5 0.6 0.7 0 0 0 0 NA t120 3.2 1.6 2 1.4 0 0 0 1 NB1 t0 0.8 0.7 1 1.1 2 1 4 1 NB1 t120 16.2 15.8 13.9 20.7 3 2 4 4 NB2 t0 0.5 0.7 0.7 0.6 0 2 2 0 NB2 t120 13.7 15.9 14.1 18.7 3 4 2 3 NV = after pre-purification refinements; NA = after nano-emulsifying refining with an arginine solution, NB = after treatment of the pre-cleaned oils with bleaching earth 1 or 2.

(68) Results:

(69) In 3 of the 4 investigated oils, phosphorus levels were above the limit of the process specification, so that a pre-purification step with an acid treatment was carried out. Thereafter, the phosphate content was below 15 ppm (mg/kg) in all oils; however, the investigation for the presence of mucilages remained positive in all of the pre-cleaned oils; thus, a further pre-purification with an aqueous alkaline solution was carried out. This refining step had to be repeated for one of the oils; thereafter sufficient reduction of mucilages was obtained in all oils, and the analytical results were then in accordance with the process specifications. Refining of these oils with an aqueous solution of arginine by using an intensive mixing procedure was possible in all oils. Accordingly, an emulsion-free phase separation could be achieved in all oils. The oils obtained had a yellow tint of low to medium intensity. The color spectrum of the refined oils according to visual assessment and to the Lovibond color scale measurements was comparable to that of oils that have been bleached with bleaching earths. This also holds true for the achieved reduction of the absolute chlorophyll concentrations of oils refined by the inventive mixing process and that were obtained after bleaching with bleaching earths.

(70) The content of secondary oxidation products could be reduced by the pre-purification process and further reduction was achieved by subsequent aqueous extraction by means of an arginine solution, which was then below the detection limit. Reduction of secondary oxidation products was also achieved by bleaching earths in the pre-purified oil. During the course of 120 days, there was an increase of secondary oxidation products in the raw oils and the pre-purified oils. In pre-purified oils treated with bleaching earths, there also was a significant increase of secondary oxidation products, while there was only a minimal increase over time in oils obtained after nano-emulsifying refining using an arginine solution. The raw oils had several unpleasant smells and off-flavor characteristics. After pre-purification the off-flavors persisted at a lower level of intensity; however, further off-flavors developed, thus, causing the sensory characteristics soapy and astrigent. A complete or almost complete reduction of off-flavors and unpleasant smells could also be achieved in oils obtained from nano-emulsifying refinement with an arginine solution and bleaching earths. In the further course, the intensity of unpleasant smells and off-flavor characteristics in the crude oils and the pre-purified oils increased. While some unpleasant smells and off-flavors arose during the storage period in oils treated with bleaching earths, this was not the case in oils refined by the inventive mixing procedure.

(71) In the separated aqueous phase after refining with arginine chlorophyll, phospholipids, free fatty acids and tocopherols were found. The phases had a green-yellow color and a spicy to musty smell. Due to a strong astrigent characteristic of these aqueous solutions in the mouth, no sensory tastings were performed here.

Example 6

(72) Investigation on the Deodorization of Vegetable Oils

(73) Investigated were 6 vegetable oils, which had a significant amount of unpleasant smells and off-flavors due to extraction conditions, aging, or storage conditions, or their natural taste quality was impaired. For this purpose, a sunflower seed oil (SSO), in which the kernels were pressed without peeling and then were deoiled by means of a solvent extraction procedure, was used. The oil fractions obtained were merged. The oil had a brownish color; approximately 8 vol % of a brown gum phase had sedimented after a 12-h standing time. Further, a cold-pressed rapeseed oil (RO) was investigated, which has been stored in barrels for 18 months. The oil had an intensely brown-green color and was slightly turbid; after a 10-hour standing time 5 vol % brown gum phase had sedimented. Further, sesame oil (SO) was examined which had a yellowish-brownish color. Further investigated was an olive oil obtained by hot-pressing (OO) that has been stored for a period of 8 months. This had an intense olive-colored slightly turbid appearance. Furthermore, a cold-pressed walnut kernel oil (WKO), which had a brownish color, was investigated.

(74) For the studies, 1.5 kg of each raw oil was refined.

(75) The oils were analyzed concerning the key parameters according to Example 1 (Table 6.1). Since the process limit for phosphate was exceeded in SSO, RO, and OO, a pre-purification step with phosphoric acid (85 vol %, addition volume 0.2 vol %) was performed using an intensive mixing procedure by means of an Ultraturrax T18 (IKA, Germany) (24,000 rpm for 5 minutes). Then phase separation with a beaker centrifuge (3,500?g, for 5 minutes) was performed. The investigation for the presence of mucilages (performed in accordance to example 2) was positive in the 3 prepurified oils (phosphorus contents here: SSO 28 ppm (mg/kg), RO 12 ppm (mg/kg), OO 22 ppm (mg/kg)) and the other oils: SSO 4.3 vol %, RO 3.8 vol %, SO 5.2 vol %, OO 4.8 vol %, WKO 6.2 vol %. A pre-purification step was performed with an aqueous sodium metasilicate pentahydrate solution (20 wt %, volume addition 3 vol %) by means of an intensive mixing procedure using the identical set up and settings as in the previous pre-purification process, in SO and WKO. Hereafter the investigation for the presence of mucilages was still positive for two of the oils: SO 2.2 vol % and WKO 3.4 vol %. Then all of the oils obtained from the previous pre-purifications were subjected to a further pre-purification step with an aqueous sodium carbonate solution (25 wt %, volume addition 4 vol %) by means of an intensive mixing process, performed as described above. Phase separation was carried out with a beaker centrifuge, as performed before. The investigation for the presence of mucilages was then negative (<1.0 vol %) in all pre-purified oils and phosphorus contents were <10 ppm (mg/kg) in all. Subsequently, refining with an arginine solution (0.3 molar, volume addition between 1.5 and 4 vol %) was performed in all oils by means of an intensive mixing process as described above. Subsequently, phase separation was performed, as described above; analyses according to the procedures in Example 1 were conducted.

(76) TABLE-US-00008 TABLE 6.1 Phos- Magne- Potas- Cal- Muci- phorus FFA sium sium cium lage Refining step [mg/kg] [wt %] [mg/kg] [mg/kg] [mg/kg] (vol %) SSO- raw 725 1.9 68 56 94 11.5 * SSO - refined 2 0.02 0.05 <0.02 <0.02 0 RO - raw 74 1.1 26 2.3 21 7.7 RO refined - 0.5 0.01 <0.02 <0.02 <0.02 0 SO - raw 9 0.43 6.4 0.5 8.6 5.2 SO - refined 0.5 0.01 <0.02 <0.02 0.03 0 OO - raw 234 1.4 54 12 46 9.6 OO - refined 2 0.09 0.04 <0.02 <0.02 0 WKO raw 12 0.6 12 1.8 15 6.2 WKO-refined 0.5 0.07 <0.02 <0.02 <0.02 0 Mucilage: Relative volume fraction of an emulsion phase recognizable in an investigation for the presence of mucilagest. * No more free water phase, the volume of the semisolid emulsion mass exceeds the water volume added.

(77) The raw oils and the oils obtained after nano-emulsive refining were evaluated by 4 qualified tasters in accordance with the Guidelines for edible fats and oils of the German Food Code, and in accordance with the procedure in Example 4 after the oils had previously been subjected to vacuum drying.

(78) The median of all tasting results for the investigated oils was calculated (Table 6.2).

(79) TABLE-US-00009 TABLE 6.2 SO - SO - RO - RO - SSO- SSO- WKO- WKO- raw refined raw refined raw refined raw refined Seed-like 2 4 2 4 2 3 2 4 Nutty 1 2 0 3 0 0 3 5 Fruity 0 0 0 0 0 0 0 1 Rancid 6 0 5 0 3 0 4 0 Woody 1 0 2 0 1 0 1 0 Fusty 3 0 0 0 3 0 0 0 Musty 6 0 3 0 3 0 3 0 Astringent 5 1 4 0 1 0 4 0 bitter 4 0 5 0 2 0 5 0 Sum of 25 1 19 0 13 0 17 0 off-flavors

(80) Results:

(81) The investigated aged oils, which had a large amount of off-flavors and odorants, had to be refined by a 1- or 2-stage pre-purification processes due their content of phosphate and/or mucilages; thereby the process parameters were achieved that are required to qualify for the nano-emulsifying refining. This could be performed with an arginine solution; the obtained reaction mixtures could be separated into two phases by using centrifugal phase separation. The obtained aqueous phases exhibited a marked turbidity and a green, greenish-yellow, or yellow-brownish color. Further, the aqueous phases had an intense plant smell, partly with a musty to pungent character. The flavors and odorants that caused the sensory perception of an off-flavor or an unpleasant smell could be removed virtually completely in all refined oils. On the other hand, a more intensive perception of sensory characteristics that are typical for the respective oils was noticed.

Example 7

(82) Investigation on the Production of Water-in-Oil Emulsions by Homogenization and their Effect on the Bleaching and Deodorization of Lipid Phases.

(83) Two process techniques were investigated: mixing procedures archived in a batch process (batch process) or due to a continuous mixing procedure (inline process). The batch mixing process was conducted with a turbulence mixer device (SRT4 1500, Black, Germany) (V1+V2) and a rotor-stator homogenizator (Fluco, MS23, Fluid Kotthoff, Germany) (V3+V4). The inline mixing process was carried out with an inline dispersion unit (Fluko DMS2.2/26-10, Germany) with 1 or 3 consecutively aligned dispersion units (R/S-units) (gap diameter 1 mm) as indicated in Table 7.1 (V5-V10) using different flow rates. The energy demand of each investigation was documented. For conduction of the batch process, the entire volume of the aqueous phase was added to the oil (100 kg), which was in a container having a bottom diameter of 47 cm, before start of the mixing process; the homogenizer and the turbulence mixing device were set to have a ground clearance of 10 cm. The in-line mixing system was fed by means of two metering pumps, which allowed a continuous flow with defined flow rates of the two phases through tubing; flow rates are given in Table 7.1. The volume ratios of the admixed aqueous phases are also listed in Table 7.1. The tubings conducting the two phases merged directly in front of the dispersing tool.

(84) Sesame press oil was used having the following key values: phosphorus 25 ppm (mg/kg), calcium 54 ppm (mg/kg), magnesium 23 ppm (mg/kg), iron 7 ppm (mg/kg), acid number 1.1 wt %, chlorophyll 36 ppm (mg/kg). A pre-purification process was carried out with a sodium carbonate solution (20 wt %, volume addition 4 vol %) by the use of the various mixing modalities. The obtained reaction mixtures were conducted through a separator (OTC 350, MKR, Germany) (flow rate 30 L/h, 10,000 rpm). In the pre-cleaned oils investigation for the presence of mucilages was carried out as performed in Example 1. It was positive in V1 (2.2 vol %); therefore, here, the pre-purification step was repeated. Then in all the pre-purified oil phases, the investigation for the presence of mucilages was negative (<1.0 vol %) and phosphorus was <8 ppm (mg/kg) in all of them. Thereafter, the pre-purified oils were refined with an arginine solution (0.4 molar, 3 vol %) where an identical mixing or homogenization procedure was performed as done in the individual pre-purification steps using the same mixing and dispersing tools and settings according to Table 7.1. Subsequently, phase separation was carried out with the separator mentioned above under the same process conditions as previously mentioned.

(85) The key values of the refined oils were determined (measurement methods). The oils were dried after refining as describe in Example 1. The chlorophyll content was determined according to Example 5.

(86) TABLE-US-00010 TABLE 7.1 Diameter Number Process propeller */ of R/S Rotational Duration (Min)* Energy No. mode rotor ** (mm) units frequency flow rate (L/Min)** applied (W) V1 Batch 100* n. a. 750 90 Min * 126 V2 Batch 100* n. a. 1500 90 Min * 378 V3 Batch 180* 1 1250 5 Min * 134 V4 Batch 180* 1 1250 10 Min * 262 V5 inline 74** 1 1000 60 L/Min ** 120 V6 inline 74** 1 1000 20 L/Min ** 240 V7 inline 74** 3 1000 60 L/Min ** 143 V8 inline 74** 3 1000 20 L/Min ** 52 V9 inline 74** 1 2800 60 L/Min ** 335 V10 inline 74** 1 2800 20 L/Min ** 126 na = not applicable; R/S = rotor-stator

(87) The emulsification that was obtained after an individual mixing process of arginine solutions was characterized by a turbidimetry measurement (InPro 8200, Mettler Toledo, Germany) as well as by determination of the droplet sizes by dynamic laser light scattering analysis (DLS) (Zetasizer Nano S, Malvern, UK). All samples were analyzed 1 and 15 minutes after finishing of each mixing or homogenization process. The intensity of turbidity and the average diameter of the fraction(s) of droplets that accounts for >90% of all measured droplets, determined by DLS, are given in Table T2. A sensory tasting test was carried out by four trained tasters, according to the procedure outlined in Example 4. The intensity values of all characteristics of unpleasant smells and off-flavors were summed up for the respective raffinates and listed in Table 7.2 (Sum off-flavors). The maximum value possible for the sum of all the eventual unpleasant smells and off-flavor intensities was 50. In the investigations V1, V2, C4, V8, and V10 and the raw oil samples were taken to investigate the storage stability accordingly to Example 2 (the refined oils were subjected to vacuum drying); the anisidine value was determined at t0 and t120. The difference between the value present at t0 and that present at t120 was calculated. These samples were also used for the determination of the color spectrum by the Lovobond method. The difference for obtained values of red (R) and yellow (Y) between the value present at t0 and at t120 was calculated for the individual investigation.

(88) TABLE-US-00011 TABLE 7.2 Turbidity Droplet size Phos- Acid (FTU) (?m) phorus value Chlorophyll Off- 1 Min 15 Min 1 Min 15 Min ppm wt % ppm flavors V1 932 534 6.13 9.2 28 0.24 0.43 6 V2 2411 820 1.23 4.93 1.4 0.13 0.12 3 V3 3036 2588 0.48 0.61 1.1 0.05 0.01 0 V4 3225 2886 0.38 0.59 1.2 0.02 0.01 0 V5 1558 938 1.43 3.45 1.8 0.07 0.09 2 V6 2866 988 0.92 1.05 1.3 0.05 0.05 2 V7 2988 2556 0.43 0.67 0.8 0.01 0.02 0 V8 3721 3101 0.38 0.49 0.9 0.01 0.01 0 V9 3520 3145 0.45 0.69 1.0 0.01 0.01 0 V10 3655 3005 0.27 0.38 0.05 0.01 0.01 0

(89) Results:

(90) In the pre-purified oil phases, obtained by the different mixing procedures and where the process indicators accorded to the process specifications, admixture of arginine solutions could be performed by mixing or homogenization with all of the mixing processes. Thus, subsequent phase separation was possible without presence of an emulsification in the obtained oil or water phases. Reductions of off-flavor or odorants and of chlorophyll were achieved in all refined oils; however, the extent was less when the mixing process was performed by a propeller mixer or a dispersion mixer executing low shears forces as compared to a nano-emulsifying refining, despite an equal or even higher amount of energy applied for the mixing process. This finding was paralleled by the presence of higher values for phosphorus and the acid number. Correspondingly, the droplet sizes were significantly smaller and show no relevant tendency to coalesce in oils, in which an optimal depletion of mucilages was achieved; therefore, sustainability of the emulsion has been increased significantly.

(91) The total amount of the intensities of characteristics of an unpleasant smell or off-flavor of the raw oil was 19. There was a depletion of unpleasant smell or off-flavor by using a mixing process according to the invention utilizing low shear forces. However, complete depletion of unpleasant smell or off-flavors could be achieved only by the use of a nano-emulsifying intensive mixing process where stabilized emulsions have been obtained with durable droplet sizes that were <1 ?m even 15 minutes after manufacturing. The aqueous phases obtained after phase separations were turbid and had a green color. The turbidity was stronger when the nano-emulsifying refining was carried out with a high shear rate or when there was a longer contact time in the dispersion unit. All water phases had an intense woody and musty smell. A significant increase of secondary oxidation products was observed in the raw oil after storage for a period of 120 days at room temperature and exposure to light to (anisidine: +17.5). In the refined oil phases of V1 and V2, there was a slight increase of oxidation products (anisidine: +3.2 and +2.1), while in investigations V4, V8, and V10 virtually no increase occurred (anisidine: +0.6, +0.4, +0.3). In the stored raw oil, there was a change in color (R +5/Y +16). In the refined oils there was only a slight (V1: R +2/Y +5) or minimal change of color (V2: R +1/Y +2; V4: R +1/Y +1; V8: R +/?0, Y ?1; V10: R +/?0/Y ?2).

Example 8

(92) Investigation on the Effect of Mucilage on the Homogenizability of Lipid Phases

(93) For the tests, safflower oil that had the following key parameters was used: phosphorus 25 ppm (mg/kg), calcium 32 ppm (mg/kg), magnesium 12 ppm (mg/kg), iron 3 ppm (mg/kg), acid number 0.8 wt %, chlorophyll 16 ppm (mg/kg). The investigation for the presence of mucilages (according to example 1) exhibited an emulsion phase having a volume fraction of 8.2 vol %. One kilogram samples of each of the raw oils were used for conduction of various pre-purification processes. The pre-purification steps were directed to a reduction of mainly phosphorus-containing compounds or phosphorus-containing mucilage or to remove both from the oil. Determination of contents of phosphate and free fatty acid and conduction of the investigation for the presence of mucilages were performed as in Example 1; droplet sizes formed in the emulsions (1 minute after finishing of mixing) as well as their durability (15 minutes after finishing of mixing) were determined by means of DLS (see measure methods). Determination of the chlorophyll content of the refined oil phases was performed after drying of the lipid phases (see measure methods). Pre-purifications were performed according to the following schemes: trial 1: sodium hydroxide (1 molar, volume addition 2 vol %), trial 2: sodium hydrogen carbonate (10 wt %, volume addition 1.5 vol %), trial 3: sodium carbonate (20 wt %, volume addition 2 vol %), trial 4: phosphoric acid (85 wt %, amount 0.2 wt %) and after phase separation sodium carbonate (10 wt %, volume addition 2vol %), trial 5: sodium metasilicate (10 wt %, volume addition 1 vol %), trial 6: citric acid (25 wt %, volume addition 1.0 vol %) and after phase separation sodium carbonate (15 wt %, volume addition 3 vol %), trial 7: phosphoric acid (85 wt %, volume addition 0.3 vol %) and after phase separation sodium carbonate (15 wt %, volume addition 2 vol %).

(94) The mixing process was performed with an Ultraturrax (T18, 24,000 rpm) for 5 minutes. Then phase separation was carried out with a beaker centrifuge (3,800 rpm, 10 minutes) and samples were taken for analyses. Thereafter, a 0.3 molar arginine solution (volume addition 2 vol %) was added to the pre-purified oil phases and homogenized by the Ultraturrax (24,000 rpm, 5 minutes). Subsequently, phase separation, as previously described, was performed. Samples were taken for analyses and chlorophyll determination, which was carried out after drying of the oil sample.

(95) Results:

(96) The oil tested had phosphorus levels and a mucilage load that were higher than the set limits of the process indicators. When trying to homogenize the oil with an arginine solution, a solid emulsion formed. Various pre-purifications were applied, whereby reduction of mucilages or phosphorus compounds, respectively, from the oil phases was achieved. A reduction of phosphorus-containing compounds alone that complied with the process specification was not sufficient to enable good separability of phases when mixing with an arginine solution via an intensive mixing process; thus trial 1 could not be finished. For oils, in which the phosphorus content and/or the amount of mucilage was only slightly above the set limits of the process indicators, the reactive mixtures produced with the arginine solutions were separable. However, droplet dimensions in the reactive mixture were significantly greater in those oils, as this was the case in oils where the achieved reductions of phosphorus-containing compounds and mucilages accorded to the process indicators. Due to the staged purification approach with a nano-emulsifying refining process, considerable reductions of phosphorus-containing compounds, the acid value, and chlorophyll concentrations could be achieved in all the oils. However, depletion was much more efficient when contents of mucilage and phosphorous-containing compounds were within the limits of the process specification, after performance of a pre-purification step.

(97) TABLE-US-00012 TABLE 8 Acid Acid Droplet size Trial AWT Phosphorus value 1 Phosphorus value 2 (?m) Chlorophyll No. (Vol-%) 1 (ppm) (wt %) 2 (ppm) (wt %) 1 min. 15 min. (ppm) 1 6.6 18.8 0.25 n. a. n. a. n. a. n. a. n. a. 2 3.5 18.1 0.48 5.3 0.23 1.3 4.6 2.32 3 2.8 9.5 0.32 3.1 0.18 0.89 1.56 2.11 4 1.8 4.6 0.88 1.8 0.21 0.65 0.98 1.62 5 1.1 16.6 0.61 2.9 0.15 0.68 1.23 3.2 6 <1.0 3.2 0.32 1.4 0.01 0.39 0.48 0.06 7 <1.0 2.8 0.21 0.5 0.01 0.25 0.34 0.01 n. a. = not applicable because phase separation not obtainable AWT = Volume fraction of an emulsion layer observed in an investigation for the presence of mucilages Acid number 1 = Number of titrable acid equivalents in the pre-cleaned oil Phosphor 1 = phosphorus content of the oil after pre-purification Acid number 2 = Number of titrable acid equivalents in the oil after nano-emulsifying refining with an arginine solution Phosphor 2 = Phosphorus content of the oil after nano-emulsifying refining with an arginine solution

Example 9

(98) Investigation for Use of Nano-Emulsions for Deodorization and Bleaching of Animal Fats

(99) A hexane extraction fraction of animal fat (K1) with a dark brown color and a pungent-putrid and rancid odor had the following oil characteristics: phosphorus 5.2 ppm (mg/kg), calcium 12.4 ppm (mg/kg), magnesium 4.3 ppm (mg/kg), iron 3.1 ppm (mg/kg), acid value 0.4 wt %. The investigation for the presence of mucilages (implementation in accordance with Example 1) showed a complete emulsion of the water phase (9.0 vol %). A 3 kg sample of the animal fat was heated to 45? C. and a mixture of sulfuric/phosphoric acid (v:v, 20:80, 95 wt %/85 wt %) was admixed (volume addition 1 vol %) by homogenization with an Ultraturrax T25 (25,000 rpm) for 8 minutes. After standing for 30 minutes, phase separation was carried out with a separator (OTC 350, MKR, Germany, flow rate 10 l/h, 10,000 rpm). This gave a clear oil, as well as a dark-brown viscous water phase. The oil still had a dark brown color, the smell was only slightly reduced, while additional odors were a sulfur and an acid smell. In the investigation for the presence of mucilages, there was an emulsion layer with a volume fraction of 4.3 vol %. Therefore, a further pre-purification was conducted with an aqueous solution of sodium metasilicate (20 wt % , volume addition 3 vol %), which was homogenized with the Ultraturrax for 5 minutes. Then phase separation was performed with the above-described separator and process conditions. The lipid phase separated was moderately turbid, the color character has not changed, and the initial burden of off-flavors still remained. The key characteristics of that oil were: phosphorus 3 ppm (mg/kg), calcium 0.2 ppm (mg/kg), magnesium 0.05 ppm (mg/kg), iron 0.02 ppm (mg/kg), acid number 0.15 wt %. The investigation for the presence of mucilages was negative (<1.0 vol %). In order to improve the extraction of dyes or odorants, 200 g samples of the precpurified oil were treated with the following nano-emulsions, which were composed of an aqueous arginine solution (0.6 molar), in which the following carboxylic acids had been dissolved by stirring over a period of 12 h at 35? C.: 1) oleic acid (0.2 molar) and naphthenic acid (0.05 molar); 2) palmetoleinic acid (0.1 molar) and caprylic acid (0.2 molar); 3) capric acid (0.1 molar) and benzene-1,2,4,5-tetracarboxylic acid (0.05 molar) and embonic acid (0.1 molar); 4) hydroxy-phenylpropionic acid (0.2 molar) and syringic acid (0.2 molar). For comparison, analogous trials were conducted with the following: 5) an aqueous arginine solution (0.6 molar), 6) an aqueous solution of sodium hydroxide (1 molar), and 7) a water phase without additives.

(100) The nano-emulsions and the comparison solutions were added to prepurified oil phases in a volume ratio of 5 vol % and then were homogenized with an Ultraturrax T18 (24000 rpm) for 8 minutes. Then phase separation was performed with a centrifuge (4,000 rpm/10 minutes). From the resulting oil phase, samples were taken for analyses as well as for a tasting and color analysis. For the latter, the oils were first subjected to vacuum drying according to Example 1. Tastings of raw material deviated from the previous protocol in that only an in-depth examination of the odor accompanied by evaluation of sensory effect of a drop that was given to the tongue was performed. For the characterization of off-flavors, other attributes (Table 9.2) were selected. Otherwise the tastings were carried out as outlined in Ex. 4. The color of the lipid phase was evaluated by the EBC color scaling spectrometry with a Lovibond ColorPod (range 2-27). The color scale of the animal body fat was 24.sup.th.

(101) TABLE-US-00013 TABLE 9.1 Phosphorus Acid value Trial No. (ppm) (wt %) Calcium (ppm) Lovibond EBC 1) 0.8 0.02 <0.02 6 2) 0.6 0.04 <0.02 6 3) 0.9 0.06 <0.02 7 4) 0.6 0.04 <0.02 6 5) 0.7 0.01 <0.02 7 6) 2.5 0.12 0.2 8 7) 3.1 0.15 0.2 8

(102) TABLE-US-00014 TABLE 9.2 Raw material V1) V2) V3) V4) V5) V6) V7) chemical 4 0 0 0 0 0 3 3 fishy 7 1 0 0 1 2 4 5 sour 2 0 0 0 0 0 0 1 rancid 7 0 1 0 0 0 3 3 soapy 2 0 0 0 0 0 4 2 fusty 5 1 0 0 0 1 0 0 musty 6 0 1 0 0 1 2 0 astringent 6 0 0 0 1 1 2 3

(103) Results (Numerical Results are Summarized in Tables 9.1 and 9.2):

(104) In the solvent-extracted animal fat phase, relevant amounts of mucilage and a moderate amount of phosphorus-containing compounds were present. By pre-purification processes, the contents of mucilages and phosphorus-containing compounds could be lowered to the required level according to the set process limits. The content of fatty acids was <0.2 wt %; thus, nano-emulsions were provided to improve nano-emulsifying refining with an arginine solution by means of an intensive mixer. Phase separation was possible without significant emulsions of the separated phases. The separated water fractions were very turbid and had a brownish color and an intense and unpleasant odor. The key characteristics of the oils obtained are given in Table 9.1.

(105) The aqueous nano-emulsifying refining procedure by means of an arginine solution of the prepurified oils resulted in a very good reduction of contents of phosphorus and compounds with acidic groups as compared to the other aqueous extractions. Furthermore, a superior reduction of dyes and odorants could be achieved. However, more superior reductions of unpleasant odorants flavors and of dyes were obtained in pre-purified lipid phases by means of nano-emulsion admixed by an intensive mixing procedure ,

Example 10

(106) Large-Scale Application of an Aqueous Refining Process.

(107) A sample of 2000 kg soy screw-pressed oil with key oil parameter: phosphorus 37 ppm (mg/kg), calcium 5.2 ppm (mg/kg), magnesium 2.9 ppm (mg/kg), iron 1.4 ppm (mg/kg), acid value 0.85 wt %, chlorophyll 8.2 ppm (mg/kg) was prepurified because the phosphate content was >15mg/kg by the use of a citric acid solution (8 wt %, volume addition 3 vol %). The raw oil and the aqueous refining liquid were heated to 28? C. The mixing was carried out with an in-line rotor-stator shear mixer (Fluco DMS 2.2/26-10, Fluid Kotthoff, Germany); rotation frequency was set to 2,500 rpm. The raw oil (tank 1) and the aqueous phase (tank 2) were each conducted through a line at a constant flow provided by eccentric screw pumps (PCM EcoMioneau C, type MM25C6S and type MM1C12S, Germany) which was adjusted according to the preset ratio of admixture. The throughput volume of the oil phase was 2.5 m.sup.3/h. The lines merged in front of the dispersing tool to which they were connected to and the metering was obtained in the according doses volumes. After in-line intensive mixing, the reaction solution was pumped through a line into tank 3, which served as a volume buffer. From there it was pumped to a plate separator (AC 1500-430 FO, Flottweg, Germany; 6600 rpm, centrifugal acceleration 10,000?g).

(108) The separated oil phase, which had a temperature of 32-35? C. was pumped through a pipe into tank 4. From a sample taken there, investigation for the presence of mucilages was carried out as outlined in Example 1, showing a semisolid emulsion layer of 0.3 ml (3.4 vol %). A further pre-purification procedure was performed with sodium hydrogen carbonate (20 wt %, volume addition 4 vol %) carried out with the above sequence of inline homogenization (hereinafter introduction into tank 5) and subsequent phase separation with a separator at the same settings and conditions as previously used. The separated oil phase was pumped into the tank 6 (temperature 35? C.). Analyzes of samples taken from there revealed: phosphorus 1.8 ppm (mg/kg), calcium 0.09 ppm (mg/kg), magnesium 0.05 ppm (mg/kg), iron 0.02 ppm (mg/kg), acid number 0.23 wt %; investigation for the presence of mucilages showed only a thin membrane at the phase boundary (<1.0 vol %).

(109) For the nano-emulsifying refining an aqueous (low ion water) arginine solution (0.4 molar) was prepared and admixed with a volume fraction of 2 vol % homogenized with the in-inline mixer. The reaction mixture was fed into tank 7) and from there to the separator by which phase separation was obtained using identical settings and conditions as before. The refined oil was pumped into the tank 8 and had a temperature of 37? C.

(110) For process control intensity of emulsification was monitored by continuous measurement of the turbidity of the reaction mixture in tank 7 by turbidimetry (InPro 8200, Mettler Toledo, Germany) in a continuous fashion. Intermittently, samples were taken to measure droplet sizes present in the reaction mixture. These samples were measured after 1 minute and 15 minutes with a DLS method according to Example 7. Determination of oil characteristics, the chlorophyll content and the investigation for the presence of mucilages were carried out according to examples 1, 2, and 5. A tasting of the refined oil was performed by 4 trained examiners according to Example 4, and test results were summarized according to example 7. Determination of 3-MCPD esters and tocopherols was carried out as stated in the measurement methods section.

(111) Results:

(112) The raw oil had a content of phosphorus compounds and mucilages that were outside the set limit of process indicators. By means of two pre-purification process steps, executed as a continuously performed production process utilizing intensive mixing of the process liquids, an oil phase suitable for nano-emulsifiying refining was achieved. Nano-emulsifying refining with an aqueous arginine solution was possible and a highly efficient and durable emulsification was achieved. The turbidity of the homogenized solution with an arginine oil emulsion was 3600-3900 FTU. The DLS measurements documented particle sizes between 0.25 and 0.31 pm after one minute and between 0.35 and 0.41 pm after a 15 minute standing time. This water-in-oil emulsion was separated with a separator into an oil and a water phase. The oil phase was largely depleted from impurities and had the following oil characteristics:

(113) phosphorus 0.7 ppm (mg/kg), calcium <0.02 ppm (mg/kg), magnesium <0.02 ppm (mg/kg), iron <0.02 ppm (mg/kg), acid number of 0.05 wt %, chlorophyll 0.02 ppm (mg/kg). The sum of intensities of off-odors or an unpleasant taste for the raw oil was 18. After pre-purification, the sum was 12, wherein a new off-taste characteristic (soapy) was realized (intensity level 3). After nano-emulsifying refining with the arginine solution, the sum of off-flavors and unpleasant smell characteristics was 0. The characteristics counted as typical, namely seed-like and nuttiness, were found to be more intense than in the raw oil (sum crude oil 4, sum refined oil 8). The oil was of good visual and sensory quality and suitable for consumption. 3-MCPD esters were not detected; the content of tocopherols in crude oil was 522 mg/kg and in nano-emulsive refined oil 463 mg/kg.