Clear water-soluble plant fraction

Abstract

The present invention relates to a method for filtering steep water to obtain water-soluble plant fractions, such as clear corn steep water or a clear solution of potato-soluble substances, as well as a filtration method for producing the same, and its industrial use.

Description

Technical Field

[0001] The present invention relates to clear water-soluble plant fractions, particularly solutions of clear corn steep water and solutions of clear potato soluble substances. These can be stored for several days at ambient temperature without the appearance of deposits of insoluble substances.

Background Art

[0002] The food industry routinely fractionates plants to separate different constituent substances such as starch or even fiber. For this purpose, those skilled in the art frequently use fractionation, particularly based on differences in solubility in aqueous solutions. After a plant, particularly its seeds or its tubers, are made into a powder state, they are suspended in water. Some compounds such as starch are insoluble in water and can be easily recovered, for example, by simple centrifugation. Thus, at the end of this process, by-products consisting of various soluble compounds such as salts, sugars, and amino acids are also produced. These by-products can be defined as the soluble aqueous fraction of the plant, and this fraction contains insoluble substances suspended in the aqueous phase.

[0003] For example, potato starch extraction has been used in the industry for decades. After harvesting and washing, the potato is ground in the presence of water. Then, starch and pulp, which are another name for the fibers present in the potato, are insoluble in water and are separated by centrifugation. Then, the residual solution called "potato juice" is heated to coagulate the coagulable proteins. These are then also recovered by centrifugation. A final residual aqueous solution called "potato soluble substances" is also obtained, which contains soluble proteins including amino acids, soluble sugars, and inorganic salts. Then, these potato soluble substances are concentrated to a solids content of about 30 - 50%. These potato soluble substances are an example of the "water-soluble fraction" from plants.

[0004] Corn steep water, which is generally known to those skilled in the art as "corn steep", refers to an aqueous solution obtained from the immersion of corn.

[0005] Soaking corn in water constitutes the first step in starch extraction during wet starch production. This soaking swells the corn grains and removes highly fermentable soluble substances contained within them. It involves placing the corn in a silo for a certain period of time in warm water containing a small amount of sulfur dioxide to facilitate the subsequent protein-cellulose-starch separation and to prevent the growth of undesirable microorganisms. This soaking water is then typically concentrated by evaporation.

[0006] Two essential phenomena occur simultaneously during immersion: the first involves the diffusion of soluble substances from corn grains into the immersion water, while the second involves the fermentation of these soluble substances in the immersion water by lactic acid bacteria. Immersion conditions (presence of sulfites, reducing sugars, and temperature) are favorable for the rapid development of this bacterial flora.

[0007] The main advantage of this concentrated steeping water, commonly known to those skilled in the art as "corn steep," lies in its composition of essential nutrients derived from the transfer of soluble substances from the grain. These nutrients are factors that lead to the growth of microorganisms and the production of secondary metabolites, making corn steep water an ideal source of nutrients for the fermentation, agriculture, and crop cultivation industries.

[0008] In fact, corn steeped water is a major source of organic nitrogen due to its amino acid distribution and form: free, peptides, and proteins, as well as its supply of sustained-release carbon (lactic acid) and phosphate (phytic acid). When corn steeped water is combined with one or more carbon sources (such as glucose, maltodextrin, starch, and sucrose), its high content of vitamins and trace elements brings about the benefits of corn steeped water as a nutrient source for microbial growth and the induction of secondary metabolites.

[0009] Furthermore, this constitutes a relatively inexpensive nutrient source compared to yeast extracts, which represent reference substances in this field and are also used in human food and animal feed.

[0010] Furthermore, it is known that using corn steeped water instead of a complex nitrogen source such as cotton or soy protein substantially increases the yield of antibiotics produced by fermentation.

[0011] Corn steeping water is also an excellent source of nutrients for soil or soilless plant cultivation. Its abundance of nitrogen, phosphate, and potassium nutrients makes it particularly suitable for the needs of plant growth. It also contains numerous trace elements, a rich salt content, and amino acids / peptides that have a potential biostimulating effect on plant growth. Its use not only nourishes plants but also protects them from various diseases that can impair their growth.

[0012] However, liquid forms of corn steeping water and potato soluble substances present the problem of sedimentation over time, which is particularly troublesome when it comes to transporting, storing, and pumping the products. The sedimentation of heavier insoluble substances results in a heterogeneous mixture. This mixture must be stored in a thermostat-controlled mixing tank to limit changes in its composition, which is impractical and costly. Furthermore, these insoluble particles, even in suspension, can clog dispersion nozzles during use, for example, when spraying corn steeping water or potato soluble substances onto a crop field. This is all the more true when corn steeping water or potato soluble substances are consumed in small quantities at a time by certain fermentation industries. In this case, controlling its storage is especially important.

[0013] Patent application No. 2001204410 proposes the use of centrifugation to remove these settling insoluble particles and stabilize the corn steeped water. However, it should be noted that this method is not optimal because the resulting corn steeped water is not perfectly clear (a minimum volume of 7% precipitate in the supernatant). Therefore, such products are likely to cause problems during application, for example, by clogging spray nozzles when spraying on crop fields.

[0014] The applicant has also addressed this issue and proposed a solution disclosed in International Publication No. 2021 / 074548. This method for processing a solution of corn steep water comprises the following steps in order: a) adding a neutral divalent cationic salt to a solution of corn steep water; b) adjusting the pH of the solution of corn steep water to 6-8; c) separating the liquid and solid phases of the solution obtained in step b); and d) drying the liquid phase obtained in step c) to obtain corn steep powder. This solution produces clear and sterile-stable corn steep water, although its composition is altered by the introduction of the salt. While this alteration may be useful for certain applications, it may be desirable to retain the original protein content and the composition of the original corn steep water.

[0015] This issue is also addressed in Govender E's master's thesis, "The purification of corn steep liquor as a fermentation feedstock by ultrafiltration," published in 2010. Govender E offers several solutions consisting of various pretreatments, such as correcting the pH of the corn steep water to 7 by adding ammonium hydroxide and using a decanter centrifuge or a "swirling screen." These pretreatments of the corn steep water are followed by an ultrafiltration step. However, while correcting the pH to 7 reduces the precipitate in the sterilized corn steep water, many nutrients are removed by this pretreatment, and this corn steep water is not recommended for fermentation. Furthermore, as shown in the examples, this method is carried out at high temperatures to facilitate filtration. A drawback is that some insoluble particles are solubilized, permeate the membrane, and re-settle during storage.

[0016] Those skilled in the art are still awaiting a method that will enable the production of clear water-soluble plant fractions, in particular clear solutions of corn steep water and potato-soluble substances that remain clear even after storage at ambient temperature for at least 30 days.

[0017] It is to the applicant's credit that they addressed all of these problems and found the solutions of the present invention, which will be explained in more detail in the following chapters. [Overview of the project]

[0018] According to a first aspect, the present invention relates to a water-soluble plant fraction characterized by containing less than 0.5%, preferably less than 0.25%, and more preferably 0% of precipitated insoluble particles.

[0019] Preferably, the water-soluble plant fraction is characterized by containing less than 0.5%, preferably less than 0.25%, and more preferably 0% of settling insoluble particles.

[0020] In a preferred alternative form, the water-soluble plant fraction is a solution of potato-soluble material characterized by containing less than 0.5%, preferably less than 0.25%, and more preferably 0% of precipitated insoluble particles.

[0021] According to one embodiment, the water-soluble plant fraction according to the present invention, which is preferentially selected from corn steep water and a potato-soluble substance solution, is characterized by preferably containing insoluble particles having a particle size distribution whose mode is 0.01 microns to 10 microns. When the water-soluble plant fraction is corn steep water, the mode is preferentially 0.01 microns to 0.8 microns, preferentially 0.05 microns to 0.5 microns, and preferentially 0.05 microns to 0.3 microns.

[0022] In this invention, the term "micron" means "micrometer," especially when referring to particle size.

[0023] According to one embodiment, the water-soluble plant fraction according to the present invention, which is preferentially selected from solutions of corn steep liquor and potato soluble substances, is characterized in that its protein content is 25% to 50% on a total solids basis. When the water-soluble plant fraction is corn steep liquor, its protein content on a total solids basis is 35% to 50%, preferably 37% to 47%, and even more preferably 40% to 45%.

[0024] According to a second aspect, the present invention relates to a method for filtering a water-soluble plant fraction, which is preferentially selected from solutions of corn steep liquor and potato soluble substances. As defined in the first aspect of the present invention, the water-soluble plant fraction to be filtered, which is preferentially selected from solutions of corn steep liquor and potato soluble substances, is filtered using a filter aid selected from potato starch, cellulose, diatomaceous earth, and perlite to obtain a water-soluble plant fraction, which is preferentially selected from solutions of corn steep liquor and potato soluble substances, preferably as a filtrate.

[0025] According to one embodiment, the method according to the present invention is - placing the water-soluble plant fraction to be filtered, which is preferentially selected from solutions of corn steep liquor and potato soluble substances, in the presence of a filter aid to form a mixture, and then filtering the mixture through a filter medium and / or - forming a precoat of the filter aid on the filter medium, and then passing the corn steep liquor or mixture to be filtered through the precoat, where the precoat is formed by contacting a filter aid selected from perlite, potato starch, cellulose, and diatomaceous earth with water to form a mixture, and then filtering the mixture through a filter medium to obtain a precoat containing the filter aid.

[0026] According to one embodiment, the method according to the present invention is as follows: 1. A step of supplying a water-soluble plant fraction to be filtered, which is preferentially selected from solutions of corn steep liquor and potato soluble substances Step of preparing a filtration system including a filter medium on which a precoat containing a filter aid selected from pearlite, potato starch, cellulose, and diatomaceous earth is formed Step of filtering the water-soluble plant fraction of step 1, which is preferably selected from a solution of corn steep liquor and potato soluble substances, using the filtration system of step 2 4. Optionally, conditioning the water-soluble plant fraction, preferably selected from a solution of corn steep liquor and potato soluble substances, obtained in step 3 for future use or direct use of the filtration permeate.

[0027] According to another embodiment, the method according to the invention comprises the following: 1. Step of supplying a water-soluble plant fraction to be filtered, preferably selected from a solution of corn steep liquor and potato soluble substances 2. Step of contacting a filter aid selected from pearlite, potato starch, cellulose, and diatomaceous earth with a water-soluble fraction, preferably selected from a solution of corn steep liquor and potato soluble substances, to form a mixture 3. Step of filtering the mixture from step 2 using a filtration system 4. Optionally, packaging the water-soluble plant fraction, preferably selected from a solution of corn steep liquor and potato soluble substances, obtained in step 3 for future use or direct use of the filtration permeate.

[0028] According to one embodiment, the method according to the invention uses pearlite as the filter aid.

[0029] According to one embodiment, the method according to the invention is carried out using a vacuum drum filter.

[0030] According to an alternative embodiment, the method according to the invention is carried out using a filter press.

[0031] According to one embodiment, the method according to the present invention is characterized in that filtration is carried out at temperatures of 20°C to 80°C, preferably 20°C to 60°C, and preferably 20°C to 40°C.

[0032] According to a third aspect, the present invention relates to the industrial use of water-soluble plant fractions, preferably soaking water or solutions of potato-soluble substances, obtained according to a method defined in a first aspect of the present invention or a second aspect of the present invention, as nutrients, for example, for the preparation of culture media for the fermentation industry or for plant-based foods in agriculture.

[0033] The present invention will be better understood by utilizing the detailed description set forth in the following chapters. [Modes for carrying out the invention]

[0034] According to the present invention, "water-soluble plant fraction" or its synonyms "aqueous plant fraction," "soluble plant fraction," "solution of plant-soluble substances," or "aqueous plant extract" are understood to mean fractions containing various water-soluble components of plant seeds or plant tubers. These fractions consist of various water-soluble molecules obtained after the removal and / or extraction of various insoluble fractions. One example is a fraction consisting of salts, sugars, and / or amino acids remaining in a solution in an aqueous solvent after the suspension of plant seed powder, followed by the extraction of various insoluble compounds such as starch or internal fibers.

[0035] A "water-soluble" compound refers to the ability of any compound to preferentially become soluble in aqueous solvents, specifically water.

[0036] "Solubilize" clearly refers to the general meaning of solvation, but also to any compound that is suspended in water and cannot be separated by methods such as centrifugation, filtration, coagulation, or precipitation. The solvent of the aqueous solution is preferably ambient temperature. "Ambient" means a temperature of 5°C to 25°C, preferably 10°C to 20°C, and even more preferably 12°C to 18°C. The pH of the aqueous solution is preferably near neutral or neutral. "Near neutral" means a pH of 5.5 to 8.5, preferably 6.0 to 8.0. "Neutral" means a pH of 6.5 to 7.5, preferably 7.0.

[0037] For the purposes of this invention, “corn steep,” “CSL liquor,” “corn soluble extract,” “steeped water,” “corn steeped concentrate,” and “low-drying material process water” refer to the liquid fraction consisting of steeped water from a corn grain steeping silo. The liquid fraction of conventional steeped water that can be filtered by the method of this invention typically has a solids content of 10% to 50%, preferably 30% to 50%, and more preferably 40% to 50%, and usually has a protein nitrogen content expressed as N6.25 at about 45% by weight of the solids content. Corn steeped water typically contains phytic acid at a level of 6 to 10% by weight of the solids content, lactic acid at a level of 25 to 30% by weight of the solids content, and ash at a level of about 15 to 20% by weight of the solids content.

[0038] Typically, corn steeped water is produced from corn kernels using a conventional method known in the art as corn "steeping." As mentioned earlier in the introduction, corn steeping in water constitutes the first step in starch extraction during wet starch production. This steeping swells the corn kernels and removes highly fermentable soluble substances contained within them. This consists of placing the corn in a silo for a certain period of time (known as the steeping time) in warm water containing a small amount of sulfur dioxide to facilitate the subsequent protein-cellulose-starch separation and to prevent the growth of undesirable microorganisms.

[0039] Two essential phenomena occur simultaneously during immersion: the first involves the diffusion of soluble substances from corn grains into the immersion water, while the second involves the fermentation of these soluble substances in the immersion water by lactic acid bacteria. Immersion conditions (presence of sulfites, reducing sugars, and temperature) are favorable for the rapid development of this bacterial flora.

[0040] Preferably, a person skilled in the art can use the teachings of U.S. Patent No. 4,359,528, or the teachings disclosed in European Patent Nos. 724,841 and 819,702, which belong to the present applicant.

[0041] "Potato soluble substance solution" or "potato soluble substance" refers to the soluble aqueous fraction obtained after the removal of various insoluble components, more specifically, after the extraction of starch, pulp, and heat-coagulating proteins. Conventional "potato soluble substance" fractions that can be filtered by the method of the present invention typically have a solid content of 30% to 50%, preferably 32% to 48%, and more preferably 35% to 45%, and usually have a protein nitrogen content expressed as N6.25, which is 30% to 35% by weight of the solid content.

[0042] An example of such a method is described by the applicant in French Patent No. 2496689. First, the constituent cells of the potato can be broken down by decomposing it in an aqueous medium, and then the starch and pulp (fibers) can be separated from the resulting slurry or grating. Next, the "red water" (the conventional name for the fraction thus obtained) is depleted of proteins by physicochemical coagulation (heating to the isoelectric point pH). The residual fraction obtained after coagulation is considered to be a "solution of potato-soluble substances."

[0043] According to a first aspect, the present invention relates to a water-soluble plant fraction characterized by containing less than 0.5%, preferably less than 0.25%, and more preferably 0% of precipitated insoluble particles.

[0044] Preferably, the water-soluble fraction is characterized by containing less than 0.5%, preferably less than 0.25%, and more preferably 0% of settling insoluble particles, in the corn steeped water.

[0045] In a preferred alternative form, the water-soluble fraction is a solution of potato-soluble material characterized by containing less than 0.5%, preferably less than 0.25%, and more preferably 0% of settling insoluble particles.

[0046] The water-soluble plant fractions according to the present invention, preferably solutions of corn steeping water or potato-soluble substances, have the advantage of being clear, and preferably remain clear even after storage at ambient temperature, i.e., 20°C ± 2°C, for at least 30 days.

[0047] When referring to the water-soluble plant fraction according to the present invention, preferably a solution of corn steep water or potato-soluble substance, the term "clarified" means that the water-soluble plant fraction according to the present invention, preferably a solution of corn steep water or potato-soluble substance, does not contain or substantially contains settling insoluble particles.

[0048] In the present invention, the term "insoluble particles" refers to particles consisting of insoluble substances from a water-soluble plant fraction, preferably a solution of corn steeping water or potato-soluble substances.

[0049] The term "settling insoluble particles" refers to insoluble particles in water-soluble plant fractions, preferably corn steep water or potato-soluble substance solutions, which have the characteristic of settling after being stored in corn steep water at ambient temperature, i.e., 20°C ± 2°C, for at least 30 days.

[0050] The water-soluble plant fraction solution according to the present invention, preferably of corn steep water or potato-soluble substance, is characterized by containing precipitated insoluble particles in a content of less than 0.9%, preferably less than 0.8%, less than 0.5%, preferably less than 0.25%, and more preferably 0% (i.e., not present).

[0051] Preferably, the water-soluble plant fraction according to the present invention, preferably a solution of corn steeped water or potato-soluble substance, does not contain precipitated insoluble particles.

[0052] The content of settling insoluble particles is preferably measured using Test A below. 1.160 mL of water-soluble plant fraction, preferably a solution of corn steeping water or potato-soluble substance, is introduced into a cylindrical container 10 cm high and 5 cm in diameter, and then the container is closed. 2. Prepare and store the water-soluble plant fraction, preferably a solution of corn steeping water or potato-soluble substances, at an ambient temperature of 20°C ± 2°C for 30 days. 3. Observe the presence or absence of deposits of insoluble particles at the bottom of the cylindrical container. 4. If sediment is present, measure its height in order to calculate the proportion based on the height of the container.

[0053] Therefore, for the tested water-soluble plant fraction, preferably corn steep water or potato soluble substance solution, if a deposit with a height of 1 cm is observed at the end of Test A, the content of settling insoluble particles is calculated as follows: 1 cm (height of deposit) / 10 cm (height of cylindrical container with height 10 cm and diameter 5 cm) = 0.1 = 10%. For the tested water-soluble plant fraction, preferably corn steep water or potato soluble substance solution, if no deposit is observed at the end of Test A, the content is considered to be zero (0 cm / 10 cm = 0 cm). In other words, the water-soluble plant fraction, preferably corn steep water or potato soluble substance solution is considered to be free of settling insoluble particles.

[0054] A solution of a water-soluble plant fraction, preferably a corn steep water or potato-soluble substance, according to the present invention, if it contains little to no settling particles, may still contain insoluble particles whose particle size, particularly the mode, can be measured, for example, by laser diffraction particle size analysis according to Test B detailed below.

[0055] According to one embodiment, the water-soluble plant fraction according to the present invention, which is preferentially selected from corn steep water and a potato-soluble substance solution, is characterized by preferably containing insoluble particles having a particle size distribution whose mode is 0.01 microns to 10 microns. When the water-soluble plant fraction is corn steep water, the mode is preferentially 0.01 microns to 0.8 microns, preferentially 0.05 microns to 0.5 microns, and preferentially 0.05 microns to 0.3 microns.

[0056] The terms “mode,” “D-mode,” “mode,” or “dominant value” can be used interchangeably. The mode is well known to those skilled in the art. Typically, it corresponds to the most expressed value of any variable in a given set. This generally corresponds to the maximum value of a relative frequency curve. In the case of division into classes of equal amplitude, the mode class refers to the class with the largest number. In that case, convention is to call the center of the mode class the mode.

[0057] Preferably, the particle size distribution and the subsequent calculation of the mode are performed using Test B as follows. -The apparatus used is preferably a MALVERN MASTERSIZER 3000 for wet dispersion. The wet dispersion system is preferably a HYDRO LV module having a dispersion volume of 600 mL. The liquid is placed in a tank equipped with an ultrasonic transducer resistant to strong acids (to promote dispersion of the sample and remove air bubbles). - The MASTERSIZER 3000's integrated software controls all measurement functions, product supply to dispersions, and washing. - The measurement range is 0.01 μm to 3500 μm. - Before analysis, the environment (lenses and circuitry) must be clean. Background analysis must be less than 100 energy units on the first detector (the curve profile must decrease exponentially). - The sample is generally dispersed directly in solvent: desalted water (refractive index = 1.33). The stirring speed is 1900 rpm. When adding the sample, the light shielding rate is 5% to 10%, and it must be stable before measurement. - The optical model must be adapted to the sample according to MIE theory. - Data collected in volume mode automatically includes the mode or D-mode, which is the diameter of the main population in the particle size distribution.

[0058] Preferably, the solid content of the water-soluble plant fraction according to the present invention, preferably a solution of corn steep water or potato-soluble substance, is 40% to 60%, preferably 42% to 55%, and more preferably 42% to 50%.

[0059] The solids content is measured using any protocol available to those skilled in the art. Preferably, the following so-called drying method is used. ■The necessary equipment is as follows: -103℃ kiln-dried sand Ventilated oven set to -103℃±2℃ - 70mm diameter glass crystallization dish - Oven-dried small glass rods (4-1) An oven set to 80°C ± 2°C for operation under reduced pressure of -0 to 135 mbar. - Desiccator with an effective desiccant Analytical balance with accuracy to -1 / 1000 gram ■Test Sample - Place approximately 15-20g of sand and a small glass stirrer into a crystallization dish. Place in the oven for at least 1 hour, then place in a desiccator and let it cool to ambient temperature. - Weigh the sample and introduce the accurately weighed test sample of approximately 2-3 g to be analyzed, then homogenize it using a glass stirrer. ■ Drying - Place this crystallization dish in the oven and maintain a reduced pressure of 0-135 mbar. After at least 4 hours, remove the vacuum pump and slowly fill the oven with air until atmospheric pressure is reached. Remove the crystallization dish and place it in a desiccator. - Cool to ambient temperature and reweigh. ■The solid content, expressed as a mass percentage of the product, is given by the following formula: ((m1-m2)×100) / m0 -m0 is the mass of the test sample in grams. -m2 is the mass in grams of the crystallization dish + sand + agitator. -m1 is the mass in grams of the crystallization dish + sand + agitator + product after drying. - The result is expressed to the nearest 0.1 unit.

[0060] Preferably, the solution of a water-soluble plant fraction according to the present invention, preferentially a solution of corn steep water or potato-soluble substance, is characterized in that its protein content relative to the total dry substance is 35% to 50%, preferentially 37% to 47%, and more preferably 40% to 45%.

[0061] The total protein content can be determined by any protocol well known to those skilled in the art, for example, by an assay for the total amount of amino acids. Preferably, the total nitrogen content is analyzed according to the Dumas method and the value is multiplied by a coefficient of 6.25.

[0062] The method according to the present invention According to a second aspect of the present invention, the present invention relates to a method for filtering a solution of a water-soluble plant fraction, preferably corn steep water or potato soluble matter, wherein the water-soluble plant fraction, preferably corn steep water or potato soluble matter solution to be filtered is filtered using a filter aid selected from potato starch, cellulose, diatomaceous earth and perlite, preferably to obtain a filtrate of the water-soluble plant fraction, preferably corn steep water or potato soluble matter solution according to the first aspect of the present invention.

[0063] According to one embodiment, the method according to the present invention is -A water-soluble plant fraction to be filtered, preferably a solution of corn steep water or potato soluble substance, is placed in the presence of a filter aid to form a mixture, and the mixture is then filtered through a filter medium and / or -A precoat of filter aid is formed on the filter medium, and then the water-soluble plant fraction to be filtered, preferably a solution or mixture of corn steep water or potato-soluble substances, is passed through the precoat. The method involves forming a precoat by contacting a filter aid selected from perlite, potato starch, cellulose, and diatomaceous earth with water to form a mixture, and then filtering the mixture through a filter medium to obtain a precoat containing the filter aid.

[0064] According to one embodiment, the method according to the present invention is as follows: 1. A step of supplying a water-soluble plant fraction to be filtered, preferentially from a corn steeping water or potato soluble substance solution. 2. A step of preparing a filtration system comprising a filter medium having a precoat formed on it containing a filter aid selected from perlite, potato starch, cellulose, and diatomaceous earth. 3. Using the filtration system of step 2, filter the water-soluble plant fraction of step 1 from the corn steeping water or potato soluble substance solution, preferentially. 4. Optionally, the process includes conditioning the water-soluble plant fraction obtained in step 3, preferably a solution of corn steep water or potato-soluble substance, for future use or direct use of the filtered permeate.

[0065] According to another embodiment, the method according to the present invention is as follows: 1. The process of supplying the water-soluble plant fraction to be filtered. 2. A step of contacting a filter aid selected from perlite, potato starch, cellulose, and diatomaceous earth with a water-soluble fraction to form a mixture. 3. Using a filtration system, filter the mixture from step 2. 4. Optionally, the process includes a step of conditioning the water-soluble plant fraction obtained in step 3 for future use or direct use of the filtered permeate.

[0066] According to one embodiment, the method according to the present invention uses perlite as a filtration aid.

[0067] According to one embodiment, the method of the present invention is carried out using a vacuum drum filter.

[0068] According to one embodiment, the method of the present invention is carried out in a filter press.

[0069] According to one embodiment, the method according to the present invention is characterized in that filtration is carried out at a temperature of 20°C to 80°C, preferably 20°C to 60°C, and even more preferably 20°C to 40°C. When the water-soluble plant fraction is corn steep water, the temperature is preferably 20°C to 60°C, and even more preferably 20°C to 40°C.

[0070] Preferably, the present invention comprises a method for producing a solution of a water-soluble plant fraction, preferably a solution of corn steep water or potato-soluble substance, the method being as follows: 1. A step of supplying a certain amount of water-soluble plant fraction to be processed, preferably a solution of corn steeping water or potato-soluble substance. 2. The process of preparing a filtration system containing a filter aid selected from the list of perlite, potato starch, cellulose, and diatomaceous earth. 3. Using the filtration system of step 2, filter the water-soluble plant fraction of step 1 from the corn steeping water or potato soluble substance solution, preferentially. 4. Optionally, the process includes conditioning the filtration permeate for future use or immediate use.

[0071] The water-soluble plant fraction from step 1, preferably a solution of corn steeped water or potato-soluble substance, can be prepared by any known method, for example, as described in paragraphs 27-29, 38-40, or 42.

[0072] Alternatively, it is possible to obtain pre-formed solutions of water-soluble plant fractions, preferably corn steeping water or potato-soluble substances.

[0073] A second step of the method according to the present invention comprises the preparation of a filtration system containing a filter aid selected from the list including perlite, potato starch, cellulose, and diatomaceous earth.

[0074] According to the present invention, “filtration system” means any system comprising a filter medium for retaining particles present in cone-steep water, typically selected from a list of vacuum or pressure filters. Pressure filters include filter presses, vertical frame filters, candle filters, and horizontal or vertical frame filters, while vacuum filters include rotary drum filters, rotary table filters, rotary disc filters, and in particular vacuum drum filters.

[0075] Vacuum drum filters are well known to those skilled in the art. This type of apparatus typically comprises one or more pumps, drums, sizing tanks, and scrapers.

[0076] The vacuum is created by one or two pumps, typically "liquid ring" pumps, which ensure a constant vacuum inside the drum. The created vacuum draws the liquid through the filter media layer. The drum is cylindrical and covered with a filter cloth. It usually rotates at an adjustable speed around its horizontal axis. It is partially immersed in a tank equipped with an agitator. Traditionally, there are two types of drums: sector drums and fully vacuum drums. A sector drum is divided into multiple sectors that do not communicate with each other. The filtrate is discharged using a vacuum pump into an independent manifold that performs air / liquid separation. A fully vacuum drum is not divided and is under a full vacuum. In a fully vacuum drum, the filtrate is transferred directly to a storage tank by an extraction pump immersed at the bottom of the drum. A sizing tank is a tank equipped with an agitator to ensure homogeneity of the water / filter media mixture. Its volume is proportional to the surface area of ​​the filter media. A scraper tank (or scraper) removes the clogged layer through the filtration process.

[0077] "Filter media" means any filtration surface typically used in industrial liquid filtration, in particular the filter surface of a filtration system as defined herein. This filter media is typically a filter cloth, a filter mesh, a nonwoven filter, for example, a filter cloth for a filter press or belt filter, or a filter mesh for a pressure or vacuum filter. The filter media may consist of any suitable material, typically metal, nylon, polypropylene, polyester, viscose, or polyethylene.

[0078] The terms "filtrate" and "filter permeate" refer to the liquid that has passed through the filter material, or in other words, the liquid obtained after filtration.

[0079] According to the present invention, the term "filtration aid" refers to any compound or mixture of compounds used to improve filtration quality and / or filtration rate by adding it to a liquid to be filtered and / or by pre-depositing it on the filtration surface of a filtration system in the form of a pre-coat.

[0080] Filtration aids consist mainly of inorganic or organic powders used as a precoat to improve the performance of the filtration system. The aid is diluted in a liquid (filtrate to be filtered or water) and then deposited on the filter. A precoat is then formed on the surface of the filter media. A variable amount of this filtration aid can be added during the filtration cycle to form a filter "cake" that remains porous around the filter, known as alluvial deposit. The initial volume of filtrate is often, and sometimes, reduced to the dry material content of the product to be processed.

[0081] According to the present invention, "perlite" or "expanded perlite" refers to volcanic rock composed mainly of silica. After extraction, this rock is usually thermally expanded to obtain a very fine honeycomb structure, which is then crushed and sieved to obtain precise particle size cuts. A particularly good commercially available example is Chemviron's CLARCEL FLO product, which is expanded perlite with CAS number 93763-70-3. Preferably,

[0082] According to the present invention, "potato starch" refers to starch that has been refined to varying degrees, obtained from the potato fractionation process.

[0083] According to the present invention, "cellulose" refers to the polysaccharides of the β-D-glucan series. Its repeating unit is cellobiose, which consists of two β-D-glucopyranose (glucose) units in a 4C1 chair conformation linked by a β1-4 glycosidic bond. Cellulose is the most abundant organic molecule on Earth, and this natural homopolymer is the main component of the cell walls of many plants (especially plants and trees), with content ranging from 15% to 99%. A particularly preferred commercial example is ARBOCEL® BWW 40, manufactured by JRS Rettenmaier.

[0084] According to this invention, "diatomaceous earth" refers to various types of diatomaceous earth, which are organic and fossil-derived siliceous sedimentary rocks composed of the fossilized remains of diatoms. It is also known as diatomaceous earth (kieselguhr), diatomaceous earth (kieselgur), and Celite (a lexicalized brand name used in chemistry). The particle size of diatomaceous earth is generally 10-200 μm. Due to its high porosity, it is soft and very light. The latter properties mean that it can be used in industrial filtration, particularly in wine and brewing.

[0085] Preferably, the additive has a permeability expressed in Darcy units of 0.030 to 15, preferably 2.5 to 4.6, and more preferably 2.5 to 3.5.

[0086] Preferably, filtration is carried out by heating the water-soluble plant fraction, preferably a solution of corn steep water or potato-soluble material, to a temperature of 20°C to 80°C, preferably 20°C to 40°C, and more preferably 25°C to 35°C. If the water-soluble plant fraction is corn steep water, the temperature is preferably 20°C to 60°C, and more preferably 20°C to 40°C.

[0087] After filtration, the water-soluble fraction can be supplemented with various products / compounds, such as preservatives like sorbic acid, benzoic acid, sodium bisulfite, acetic acid, or lactic acid. The water-soluble fraction can be stored in this manner, but it can also be concentrated by evaporation or spray drying, for example.

[0088] Finally, the present invention relates to the use of water-soluble plant fractions according to the present invention, preferably corn steeping water or potato-soluble substance solutions, in any industry, in particular the industries of industrial fermentation, agriculture, crop cultivation, and plant nutrition / stimulation.

[0089] According to the present invention, water-soluble plant fractions, preferably derived from corn steeping water or potato soluble substances, can be advantageously used as nutrients in the preparation of culture media for the fermentation industry or as nutrient media for plant foods in agriculture, particularly for lettuce and tomato cultivation.

[0090] The water-soluble plant fractions according to the present invention, preferably solutions of corn steeping water or potato-soluble substances, are of particular interest for spraying onto cultivated soil using a nozzle.

[0091] It can also be used in the fields of food, animal feed, and other sectors.

[0092] The present invention will be better understood by utilizing the following examples, which are not intended to limit the invention but merely refer to certain embodiments and certain advantageous properties of the water-soluble plant fractions according to the present invention, preferably corn steep water or potato-soluble substances. [Brief explanation of the drawing]

[0093] Other features, details, and advantages of the present invention will emerge from reading and analyzing the accompanying drawings.

[0094] [Figure 1] This shows an experimental apparatus for generating liquid immersion water using prior art. [Examples]

[0095] The following examples are intended to provide a better understanding of the present invention, but are not intended to be exhaustive.

[0096] Example 1: Preparation of corn steeped water according to prior art European Patent No. 0026125

[0097] Corn-steeped water is obtained according to a known method described in European Patent No. 0026125.

[0098] For the production of corn steeped water, a series of silos [Figure 1] is used, including seven stainless steel silos S1 to S7, each having a filtration bottom, a total volume of 33 liters, and a diameter of 25 cm, and capable of being filled with corn M, each equipped with the following: - Level probe 10, -The bottom of a given silo is connected on one side to the head of the next silo by pipe 12, and on the other side to the head of the silo itself or to the next silo by pipe 13 to ensure recirculation of the liquid phase of the silo itself (this pipe also serves to drain the immersion water if necessary), - A large-diameter bottom valve 14 for discharging corn, - A number of temperature-controlled water baths 16 as many circulation pumps P that circulate the liquid phase from a given silo through a heating coil to the next silo or the head of the silo in question. - Two sets of seven solenoid valves 17 and 18 are located on pipes 12 and 13 respectively and are controlled by level probes (to ensure complete covering of the corn and movement of liquid throughout the entire series of silos), A sulfite inlet pipe 19 adjusted to -1.5 g / L of sulfur dioxide, from which sulfite water is distributed at a constant flow rate, and a constant circulation level (liters of water per kg of corn) is ensured by opening the corresponding valve V1 in each silo in succession. - A 20-liter tank (not shown) receives soaking water from the silo before the corn is crushed, and is connected to each silo by pipes C1-C7 branching off from pipe 11 of each silo, and the soaking water leaving a given silo is directed to pipe 11 or pipe C by valves V2 and V3, respectively. - Evaporator (not shown) (of the type sold by KURT HERBERT Apparate-und Maschinenbau Lahr, Baden). Daily, the recovered immersion water is evaporated using this vacuum evaporator at a temperature below 60°C until 50% of the solids content is removed.

[0099] The corn used is French corn supplied by traditional suppliers to the starch industry. The selected soaking time is 40 hours, and the S02 level is set to 1.5 g / liter.

[0100] The temperature is set to 48°C ± 1°C throughout the entire series of silos. The process, involving emptying five silos every 8 hours, takes 40 hours.

[0101] The water circulation rate was gradually increased from 0.8 to 1.0-1.5 liters per kilogram of commercially available corn, and then to 1.8 liters of water.

[0102] Example 2: Tests on the removal of settling insoluble particles using a centrifugal separation system, optionally combined with pre- and / or post-chemical and / or heat treatment steps.

[0103] In this embodiment, the objective is to remove settling insoluble particles from the corn water obtained in Example 1.

[0104] The first insoluble particle removal strategy tested consists of using centrifugal force, as disclosed in Patent Application No. 2001204410, with the addition of pre- and / or post-chemical and / or heat treatment steps for the purpose of promoting / improving the insoluble particle removal performance.

[0105] An RC Sorvall Evolution centrifuge was used. To enhance / improve insoluble particle removal performance, different centrifugal forces were tested in combination with optional chemical and / or thermal pre / post-treatments. The different tests are detailed in Table 1 below.

[0106] [Table 1-1] [Table 1-2] [Table 1-3] [Table 1-4] Abbreviations used in Table 1: GG: Guar gum, XG: Xanthan gum, SDS: Sodium dodecyl sulfate, SA: Sodium alginate.

[0107] The results indicate that it was impossible to obtain less than 1% suspended particles, regardless of the applied parameters (centrifugal force of 3500G to 12,000G, use of pre-treatment / post-treatment). Since the size of the settling particles was automatically larger than 0.8 microns, laser diffraction particle size analysis was used sparingly herein. This result is consistent with the teachings of Patent Application No. 2001204410 (minimum sedimentation volume in supernatant of 7%).

[0108] Example 3: Test on the removal of settling insoluble particles using a filtration system with a filter aid.

[0109] In this embodiment, the objective is to remove settling insoluble particles from the corn water obtained in Example 1, following a second strategy that uses a filtration system.

[0110] The filtration system used is a rotary vacuum filter, also known as a vacuum drum, which is operated using a pre-coated filter aid.

[0111] Several filtration aids were tested. Before filtration, each precoat of the filtration aids detailed below was applied to approximately 30 kg of the product, suspended in drinking water, and then filtered for approximately 2 m 2 The corn steep water produced using the method described in Example 1 was deposited on the filtration surface of a drum made of a filter cloth having a surface area.

[0112] Next, the obtained filtrate was analyzed. The results are shown in Table 2 below.

[0113] [Table 2]

[0114] The observations of the results are as follows: - The use of potato starch, cellulose, diatomaceous earth, and perlite produces a filtrate free of insoluble particles according to Test A. - The use of a combination of potato starch and Arbocel BWW40 30 / 05 cellulose (50:50 mass ratio) results in corn steeped water containing 5% insoluble particles after filtration according to Test A, and therefore does not appear to work. - Some filtration aids, such as wood powder, do not produce corn steeped water that does not contain insoluble particles as in Test A. - The use of perlite produces a filtrate free of insoluble particles, even at very high filtration rates, according to Test A, which is highly advantageous from an industrial standpoint.

[0115] Example 4: Effect of filtration temperature on the quality of the obtained filtrate

[0116] In this embodiment, the filtration apparatus consists of a vacuum pump, a Buchner funnel, and a 100-micron wire mesh. Before proceeding with actual filtration, a 2 cm thick cake of filter aid was formed on the filter cloth using desalinated water.

[0117] If necessary, adjust the immersion water to a 43% solids content (by adding desalted water and / or by evaporation). Preheat the various samples overnight at 20°C, 30°C, 40°C, and 50°C. Then, filtration is performed.

[0118] Next, the obtained filtrate was analyzed. Table 3 below summarizes the results obtained.

[0119] [Table 3]

[0120] The results indicate that the required quality can be achieved by using potato starch as a filter aid, but filtration must be carried out at a temperature of 40°C or lower. Higher filtration temperatures, such as 45°C, result in a decrease in the quality of the resulting filtrate. While not bound by any theory, the applicant believes that temperatures above 40°C cause solubilization of insoluble material particles, enabling their penetration. As the permeate cools, the insoluble material reprecipitations in particulate form.

[0121] Example 5: Use of ultrafiltration for treating corn-steeped water

[0122] This method reproduces the instructions from Govender E's master's thesis, "The purification of corn steep liquor as a fermentation feedstock by ultrafiltration," published in 2010.

[0123] The tests were conducted using an ultrafiltration module equipped with a 30KD PALL® tangential filtration cassette.

[0124] The immersion water used was Solulys E48. After stirring, the immersion water was centrifuged to remove as much insoluble material as possible, as described in Govender's paper.

[0125] Meanwhile, the ultrafiltration cassette was rinsed (while still stored in 0.1N NaOH), and a water flow test was performed to confirm the integrity of the cassette (flow rate before storage: 345570 g / b / min, flow rate after storage: 312453 g / b / min).

[0126] The initial out-of-schedule filtration test was conducted at a temperature of 30°C. The membrane clogged very rapidly, and the flow rate was zero. It was not possible to generate permeate to investigate its storage stability according to Test A. After dismantling, product accumulation was observed at the inlet. The cassette could not be recovered after numerous washes (water flow rate was too low).

[0127] The second test is conducted at a temperature of 40°C. The obtained permeate is stored under the conditions of Test A. More than 1% sediment is observed under Test A. This temperature allows for the generation of a sufficient amount of permeate, but at the expense of its quality.

[0128] Example 6: Preparation of a solution of potato-soluble substance according to the present invention

[0129] First, a solution of potato-soluble material with approximately 0% settling insoluble particle content was prepared by rotary filter filtration under vacuum using a filter aid, according to Test A. The filter aid tested was potato starch. Approximately 50 kg of potato starch precoat was suspended in drinking water, and then approximately 2 m 2 The potato-soluble substance was deposited on the filtration surface of a rotating filter drum composed of filter cloth of the specified dimensions, and then filtered. Thus, the potato-soluble substance was filtered at ambient temperature in a vacuum drum. The obtained filtrate (referred to herein as the solution of potato-soluble substance) was analyzed. The results are shown in Table 4 below.

[0130] [Table 4]

[0131] In the second step, a solution of potato-soluble substances was prepared by filter press filtration. In this case, a filter aid, FILTRACELL NF1100 wood fiber (supplied by Rettenmaier), was used in the alluvial process. The total filtration area of ​​the filter press was approximately 1.12 m². 2 The potato-soluble material to be filtered, maintained at 20°C and supplemented with 3% Filtracell NF1100 wood fiber, was fed into a filter press. After force feeding and compression, the filtrate was obtained. The combined filtration rate of both phases was approximately 25 kg / h / m2 on average. The percentage of settling insoluble particles in the obtained filtrate, according to Test A, was measured to be approximately 0%.

[0132] Example 7: Use of corn steeped water and potato soluble substances for use in vegetable crops

[0133] Selected to evaluate the performance of the water-soluble plant fraction according to the present invention in vegetable crops

[0134] The selected model plant is lettuce (Val d'orge variety).

[0135] The cultivation protocol is as follows: - Controlled grow cabinet (temperature 24°C at night, 21°C during the day; 16-hour photocycle; 60% humidity) - Negative control culture medium: Culture medium with an N / P / K ratio of 14:10:8 - Positive control culture medium: Culture medium containing chemical fertilizer additives with an N / P / K ratio of 20:20:20 + TE - Potting soil containing water-soluble fraction (see Table 3 below) - Different potting mixes have the same amount of nitrogen, i.e., 2.31g per plant. - Each modality consists of 12 pots of one plant, i.e., 12 plants per modality. - Cultivation period from product application: 3 weeks

[0136] To evaluate performance, the following will be assessed: - New amounts of moist substances, dry substances, and chlorophyll in the leaves - New amounts of wet and dry substances and root length

[0137] The results are shown in Table 5 below.

[0138] [Table 5]

[0139] Therefore, the following can be concluded: -Water-soluble corn and potato fractions function at least as well as those managed with chemical fertilizers. - Treatment by the method according to the present invention further improves performance with respect to both leaf and root growth.

[0140] Furthermore, the absence of settling, insoluble particles allows for dispersion through nozzles that do not clog, eliminating the problem of clogging.

[0141] Example 8: Compare corn-steeped water according to the teachings of International Publication No. 2021 / 074548.

[0142] Corn steeped water is produced in accordance with International Publication No. 2021 / 074548.

[0143] It is then stored under the conditions of Experiment A. More than 1% sediment is observed.

[0144] The method described in International Publication No. 2021 / 074548 makes it possible to obtain corn-steeped water that produces little or no insoluble precipitate when subjected to sterilization. A different technical problem is that the product does not provide the complete or near-complete absence of insoluble precipitate.

Claims

1. A water-soluble plant fraction characterized by containing less than 0.5%, preferably less than 0.25%, and more preferably 0% of precipitated insoluble particles.

2. The water-soluble plant fraction according to claim 1, characterized in that it is corn steeping water.

3. The water-soluble plant fraction according to claim 1, characterized in that it is a solution of potato-soluble substances.

4. The water-soluble fraction according to any one of claims 1 to 3, characterized by containing insoluble particles having a particle size distribution in which the mode is 0.01 microns to 0.8 microns, preferably 0.05 microns to 0.5 microns, and preferably 0.05 microns to 0.3 microns.

5. The water-soluble fraction according to any one of claims 1 to 4, characterized in that its protein content, based on total solids, is 35% to 50%, preferably 37% to 47%, and more preferably 40% to 45%.

6. A method for filtering a water-soluble plant fraction, preferably selected from a solution of corn steeping water and potato soluble substances, comprising filtering a water-soluble plant fraction to be filtered, preferably selected from a solution of corn steeping water and potato soluble substances, as defined in any one of claims 1 to 5, using a filter aid selected from perlite, potato starch, cellulose, and diatomaceous earth, to obtain a water-soluble plant fraction, preferably selected from a solution of corn steeping water and potato soluble substances, as a filtrate.

7. - The water-soluble plant fraction to be filtered, preferably selected from corn steep water and a solution of potato soluble substances, is placed in the presence of the filter aid to form a mixture, and the mixture is then filtered through a filter medium and / or - A precoat of a filter aid is formed on the filter material, and then the water-soluble plant fraction or mixture to be filtered is passed through the precoat. The method according to claim 6, wherein the precoat is formed by contacting a filter aid selected from perlite, potato starch, cellulose, and diatomaceous earth with water to form a mixture, and then filtering the mixture through a filter material to obtain a precoat containing the filter aid.

8. below:

1. A process of supplying a water-soluble plant fraction to be filtered, which is preferentially selected from corn steeping water and a potato soluble substance solution.

2. A step of preparing a filtration system comprising a filter medium having a precoat formed on it containing a filter aid selected from perlite, potato starch, cellulose, and diatomaceous earth.

3. Using the filtration system of step 2, filter the water-soluble plant fraction of step 1, which is preferentially selected from the corn steeping water and the potato soluble substance solution.

4. The method according to claim 6 or 7, optionally comprising the step of conditioning the water-soluble plant fraction obtained from step 3, preferably selected from a solution of corn steep water and potato-soluble substances, for future use or direct use of the filtered permeate.

9. The method according to any one of claims 6 to 8, characterized in that perlite is used as the filtration aid.

10. The method according to any one of claims 6 to 9, characterized in that it is carried out using a vacuum drum filter.

11. The method according to any one of claims 6 to 9, characterized in that it is carried out by a filter press.

12. The method according to any one of claims 6 to 11, characterized in that the filtration is carried out at a temperature of 20°C to 80°C, preferably 20°C to 60°C, and even more preferably 20°C to 40°C.

13. Industrial use of the water-soluble plant fraction described in claims 1 to 5, or a water-soluble plant fraction obtained as a nutrient according to the method of any one of claims 6 to 12, for example, for the preparation of culture media for the fermentation industry or for plant food in agriculture.

Images