Method for producing a filter aid for liquid filtration

Abstract

The invention relates to a method for producing a filter aid for liquid filtration, comprising the following steps: a) providing spent grain; and b) extracting and recovering the protein fraction from the spent grain; and c) deodorising the spent grain; and d) comminuting the spent grain; and e) obtaining the filter aid for the liquid filtration. The invention also relates to a filter aid for liquid filtration, and to a filter for liquid filtration, and to the use of a filter or a filter aid for liquid filtration.

Description

[0001] 'Process for producing a filter aid for liquid filtration'

[0002] The invention relates to a method for producing a filter aid for liquid filtration, a filter aid for liquid filtration, a filter for liquid filtration comprising at least one filter layer and the use of the filter according to the preamble of the independent claims.

[0003] Filter aids have played an important role since the beginning of liquid filtration, such as food and / or beverage filtration, so it is not surprising that a variety of different filter aids are known from the state of the art. In the early days of beverage filtration, for example, mass filters were used which contained a mixture of cellulose and asbestos that had to be washed by hand after filtration. Later, mixtures of diatomaceous earth and perlite found their way into filtration. Diatomaceous earth is increasingly viewed as problematic, particularly because natural mineral substances are limited in their occurrence and potential health risks to humans, nature, and the environment cannot be ruled out. This is primarily due to the low quality of the diatomaceous earth available on the market due to high demand, which exceeds actual availability.Therefore, the World Health Organization classified diatomaceous earth as a health hazard in 1988.

[0004] The state of the art therefore involves the use of organic filter aids made from natural materials, whose quality fluctuates only within narrow limits and which pose no health risks. The specific consumption of organic filter aids is up to 70% lower than that of mineral products. In practice, this not only means reduced consumption but also significantly lower sludge volumes, which are sometimes complex and expensive to dispose of. Reduced sludge volumes also contain less residual filtrate, which in practice means reduced product losses due to the disposal of the wet filter sludge.

[0005] It is known from the prior art to use filter elements based on plants, cellulose, pure or purified cellulose, and / or untreated wood fibers, as disclosed, for example, in the publication of international patent application WO 98 / 40149 A. However, these have the disadvantage that they are considerably more expensive than the controversial diatomaceous earth due to the multi-stage manufacturing process, or do not offer the same excellent filtration properties, or are of limited or poor use for liquid filtration, such as food and / or beverage filtration, due to their insufficient sensory neutrality.

[0006] A disadvantage of the filter aids known from the state of the art, however, is that they are not only complex and expensive to manufacture, but, especially in the case of diatomaceous earth, are equally complex and expensive to dispose of. Furthermore, these materials do not meet the legal requirements and / or regulations established for liquid filtration, particularly food and / or beverage filtration, so they must be subjected to appropriate chemical and / or physical treatment, such as sulfite / sulfate processes. Furthermore, they are considered hazardous to humans, nature, and the environment from a health and / or occupational health perspective.

[0007] There is therefore a great need for a process for producing a filter aid for liquid filtration, by means of which a highly effective, precoatable, food-safe filter aid can be obtained quickly, simply, reliably, and cost-effectively, which is safe from an occupational health and / or health perspective for humans, animals, and the environment, and which meets the legal requirements for liquid filtration as well as food and / or beverage filtration, with the required low sensory properties. Furthermore, the filter aid should be cost-effective, available in sufficient quantity and of high quality, and require no or only minimal chemical treatment (e.g., chlorination).The invention therefore aims to provide a process for producing a filter aid for liquid filtration, a filter aid for liquid filtration, a filter for liquid filtration comprising the filter aid, and a use of the filter aid, in order to overcome the above-mentioned difficulties and, above all, to ensure efficient and economical filtration at the lowest possible cost in an environmentally friendly and environmentally compatible manner.This object is achieved in a surprisingly simple but effective manner by a method for producing a filter aid for liquid filtration and a corresponding filter aid, a filter comprising a filter aid and the use of a filter aid according to the teaching of the independent main claims.

[0008] According to the invention, a method for producing a filter aid for liquid filtration is proposed, which comprises the following steps: a) providing and comminuting a spent grain; and b) extracting and recovering the protein fraction from the spent grain; and c) deodorizing the spent grain; and d) comminuting the spent grain; and e) obtaining the filter aid for liquid filtration.

[0009] The process according to the invention is based on the fundamental idea that spent grain, a residue generated in food processing, can be used instead of diatomaceous earth as a filter aid in liquid filtration, in particular beer filtration. Within the scope of the invention, it has been recognized that the use of spent grain already provides a product with the qualities required and / or legally required for liquid filtration, in particular food and / or beverage filtration, which, due to its origin from the liquid to be filtered or from a food and / or beverage, naturally contains no hazardous and / or non-food-safe substances that would adversely affect the sensory properties of the liquid to be filtered and / or the filtrate during filtration and would therefore have to be removed again before use as a filter aid.In other words, the filter aid does not require any processing to neutralize these substances, but does require minimal processing to adjust and / or optimize the sensory properties inherent in the filter aid. Consequently, no color-, odor-, and / or flavor-affecting substances adversely affect the filtrate and / or migrate into it. Therefore, the manufacturing costs of the filter aid are very low compared to state-of-the-art processes.

[0010] Within the scope of the invention, it was further recognized that the filter aid produced from the spent grain residue, due to its filtration properties, is particularly well suited for liquid filtration, especially food and / or beverage filtration. Due to the fibrous structure, the jagged surface, and the large pore volume, the flow rate is increased while simultaneously extending the filter service life. Furthermore, minor damage to the filter fabric is reliably bridged, which facilitates the adhesion and subsequent cleaning of the filter cake.

[0011] Furthermore, it has been recognized that spent grain is not only harmless from an occupational health and health perspective, but as a renewable raw material it is also easily, completely biodegradable, thermally usable to utilize energy, cost-effectively, and in some cases even profitably disposed of in the smallest possible volume, for example via field application, composting, foodstuffs, and / or as an additive for foodstuffs for humans and / or animals. Within the scope of the invention, it has further been recognized that proteins can be extracted and obtained from the spent grain used to produce the filter aid for liquid filtration, in particular foodstuff and / or beverage filtration. These proteins can in some cases be profitably reused as foodstuffs and / or as an additive for foodstuffs for humans and / or animals.In this way, the total costs for the production of the filter aid, as well as for its disposal, can be kept as low as possible or even be profitable.

[0012] In the first step, spent grain is prepared. The term "spent grain" is known to those skilled in the art and refers to a residual material arising in food technology, such as in beer production, whiskey production, and / or the production of other grain-based beverages, which comprises residues of grain, malt, and / or other brewing and / or distilling raw materials after mashing and / or the subsequent solid-liquid separation (lautering). For the purposes of the invention, this term also includes the stillage after the distillation of a mash during spirits production. Those skilled in the art are aware that spent grain naturally contains many substances that could influence and / or impair filtration and / or the filtrate, and above all, can influence and / or impair the filtrate sensorially and / or visually, whereby this influence and / or impairment is not detrimental to the filtrate.In other words, spent grain naturally has sensory properties that influence and / or impair the filtration and / or the filtrate, i.e., substances with a color, smell, and / or taste that do not adversely affect the filtrate and / or do not adversely transfer into it. Furthermore, spent grain has a high protein content. For the purposes of the invention, it is of secondary importance whether the spent grain is provided wet, i.e., immediately after beer production, whiskey production, and / or the production of other grain-based beverages, or in a partially or fully dried state. Providing wet spent grain offers the advantage of saving drying costs, whereas partially or fully dried spent grain has a longer shelf life and, due to the volume reduction, lower storage costs without any expected loss of quality.In the next step, the protein fraction is extracted and recovered from the spent grain. This can then be reused for animal and / or human consumption, which can naturally be cost-saving or even profitable. It is known to a person skilled in the art that in step b), the extraction, i.e., the separation and / or dissolution of the proteins from the spent grain, preferably takes place using an extraction agent. Suitable extraction agents, methods, and means, as well as methods and means for recovering the protein fraction, are known to a person skilled in the art.The extraction methods for bioactive compounds known to him include, but are by no means exhaustive, supercritical carbon dioxide, extraction methods such as pressurised fluid extraction, solid-liquid extraction, solvent extraction, microwave-assisted extraction and / or ultrasound-assisted extraction, and / or hydrolysis such as hot water hydrolysis, autohydrolysis, alkaline hydrolysis, enzymatic hydrolysis and / or dilute acid hydrolysis.

[0013] The next step is to deodorize the spent grain. In this step, the sensory properties, especially those related to odor, are adjusted and / or, if necessary, reduced to a minimum. The term "deodorization" refers to the intentional removal of specific odors, fragrances, and / or colorants. Suitable methods are known to those skilled in the art.

[0014] In the next step, the spent grain is crushed using methods known to those skilled in the art, such as pressure, impact, friction, cutting, pressing, sonic, and / or impact comminution, and / or using heat, cold, and / or vibration, and means such as knives, presses, punches, crushers, shredders, and / or mills. The spent grain is preferably crushed by grinding, more preferably by wet grinding, dry grinding, and / or combinations thereof. The type of grinding is selected with regard to the degree of size reduction and fibrillation depending on the desired properties of the filter aid. It is preferably achieved that the spent grain in step d) is reduced to an average particle size of maximum 3 mm, preferably maximum 2.9 mm, 2.8 mm, 2.7 mm, 2.6 mm, 2.5 mm, 2.4 mm, 2.3 mm, 2.2 mm, 2.1 mm, 2.0 mm, 1.9 mm, 1.8 mm,

[0015] 1.7mm, 1.6mm, 1.5mm, 1.4mm, 1.3mm, 1.2mm, 1.1mm, 1.0mm,

[0016] 0.9mm, 0.8mm, 0.7mm, 0.6mm, 0.5mm, 0.4mm, 0.3mm, 0.2mm,

[0017] 0.1 mm or less. A person skilled in the art is familiar with methods and means for determining particle size, such as spectroscopy and / or methods using a multi-element photodetector.

[0018] The term "average particle size" is familiar to those skilled in the art and can be determined using known methods, such as particle size distribution. It is understandable to those skilled in the art that such a determination cannot generally be 100 percent accurate and therefore involves a statistically significant probability regarding the accuracy of the determination of the average particle size.

[0019] In the next step, the filter aid for liquid filtration is obtained with the desired and / or required properties, such as sensory properties (i.e., color, odor, and / or taste), physical properties (i.e., adjustment to a specific average particle size and / or shape), and / or chemical properties. A person skilled in the art will be aware that the particle size and / or shape can be adjusted and freely selected according to the required conditions.

[0020] The term “process for producing a filter aid for liquid filtration” refers to an energy-efficient, cost- and energy-saving, resource-conserving, efficient, and sustainable process in which the spent grain residue generated in food technology is reused to produce the filter aid. Within the scope of the invention, it is conceivable that the heat and / or energy required to carry out the process comes from renewable and / or regenerable energy sources or from waste heat. The process according to the invention can contain additional steps which lie after or between the explicitly listed essential steps a) to e). Furthermore, it is conceivable that individual steps can be repeated as often as desired. The process is preferably automatable.

[0021] The term “filter aid” is known to a person skilled in the art and refers to a substance with a fine fibrous and / or granular structure which can build up filter layers and / or filter cakes of defined permeability.

[0022] The term “liquid filtration” is known to a person skilled in the art and relates to filtration, i.e. the separation of solid particles, macromolecules, microorganisms, viruses, fungi, yeasts, spores and / or droplets from a liquid using a filter, in particular a filter with a filter aid. The liquid to be filtered is preferably a liquid foodstuff and luxury item for human and / or animal consumption and / or suitable as an additive for human and / or animal consumption. The liquid to be filtered is, for example, but by no means exclusively, wine, sparkling wine, beer, a spirit, a dairy product, juice, in particular vegetable and / or fruit juice, nectar, a soft drink, water, rainwater, wastewater, an oil, such as an edible oil, a mineral oil, a mixture and / or combination thereof, as well as their raw material and / or intermediate product.Liquid filtration includes, for example, but by no means exclusively, wine and / or sparkling wine filtration, beer filtration, spirits filtration, juice filtration, dairy product filtration, beverage filtration, particularly soft drinks, water filtration, rainwater filtration, wastewater filtration, and / or oil filtration. Product losses are preferably low, at most 1%, more preferably at most 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%.By means of the process according to the invention, it is possible, in a short time compared to the prior art, to obtain a reliable and highly efficient, food-safe, occupational health and health-safe, resource-saving filter aid from the spent grain residue generated in the food processing industry in a cost-effective, cost-efficient, and / or partially profitable manner. In addition to further use as a filter aid, it is possible to reuse the proteins extracted and obtained from the spent grain for human and / or animal consumption or as an additive for human and / or animal consumption. This not only significantly reduces costs but also represents an important contribution to sustainability, improving the ecological footprint, decarbonization, and / or improving the company's image from an ecological perspective.Furthermore, the process according to the invention can be carried out without the use of any chemical and / or health-hazardous additives, and the filter aid can be used without the use of any chemical and / or health-hazardous additives, which saves costs to a considerable extent and makes a significant contribution to environmental compatibility and / or sustainability.

[0023] Advantageous further developments of the invention, which can be implemented individually or in combination, are presented in the subclaims.

[0024] In a further development, it is conceivable that in step b) and / or after step b) as step bl) a breakdown of the fibers takes place.

[0025] The term "fiber" is known to a person skilled in the art and refers to a material consisting of fibers that can be obtained from spent grain and, if necessary, further processed. The fiber is, for example, cellulose, hemicellulose, lignin, pectin and / or lignocellulose and / or combinations thereof. A person skilled in the art knows how the fiber can be broken down simultaneously with the protein extraction in step b). The fiber is preferably broken down by cooking, preferably under pressure with liquid water at high temperatures. The temperatures are preferably 150°C to 240°C, more preferably 150°C to 210°C, for a duration of preferably 20 minutes to 90 minutes, even more preferably from 40 minutes to 90 minutes, and most preferably for a duration of 40 minutes to 60 minutes.By means of this step, it is possible to obtain a separation of hemicellulose of at least 20%, preferably of at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%. Further preferred is a separation of the soluble portion of the lignin of at least 20%, preferably at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%.

[0026] Furthermore, it is possible to carry out the digestion of the fibers following the protein extraction in step b), i.e. as step b1), preferably using a steam explosion. Here, the spent grain is heated under pressure to at least 160°C to 210°C, preferably to 180°C to 210°C, and boiled for at least 5 minutes to 30 minutes, preferably at least 5 minutes to 20 minutes, particularly preferably 5 minutes to 10 minutes. This is followed by a sudden relaxation / pressure reduction, triggering evaporation of the previously liquid phase in the spent grain, which achieves digestion of the fibers due to the sudden increase in volume.

[0027] In a further development, it is conceivable that the extraction and recovery in step b), the digestion in step b) and / or in step b1) using an extraction agent mentioned elsewhere, a temperature in the range 70°C to 240°C, preferably from 120°C to 240°C, more preferably between 120°C to 210°C, most preferably from 180°C to 210°C, more preferably from 160°C to 210°C, even more preferably between 150°C to 210°C, and / or a duration of 5 minutes to 90 minutes, preferably at least 5 minutes to 30 minutes, more preferably at least 5 minutes to 20 minutes, particularly preferably 5 minutes to 10 minutes, furthermore preferably from 20 minutes to 90 minutes, even more preferably from 40 minutes to 90 minutes and most preferably for a duration of 40 minutes to 60 minutes. Furthermore, it is conceivable that the extraction and recovery in step b) takes place at a specific pH value and / or under atmospheric pressure.The pH value depends on the type of extraction process and the extraction agent used. Experience shows that for extraction with water, the pH value is 3-7, preferably 4-6.5. When using acids as the extraction agent, the pH can be lower, while when using alkalis, the pH can be higher. The pressure is preferably in the range of 3-8 bar, preferably 4-7 bar, and most preferably 5-6 bar.

[0028] The protein fraction is preferably extracted and recovered from the spent grain by hot water hydrolysis, whereby the protein fraction is dissolved from the spent grain by boiling under pressure with liquid water at high temperatures between 70°C and 240°C, preferably at temperatures between 120°C and 240°C, even more preferably between 120°C and 210°C, and most preferably between 150°C and 210°C. Temperatures above 210°C would result in increased, undesirable degradation of proteins. A temperature of up to 210°C is therefore preferable as a compromise between protecting the protein and degrading the hemicellulose and / or lignin fraction. The duration of this process step is preferably 20 minutes to 90 minutes, even more preferably 40 minutes to 90 minutes, and most preferably 40 minutes to 60 minutes.A temperature between 150°C and 240°C and a treatment time of 40 to 90 minutes are preferable if protein extraction is to take place simultaneously with the digestion of the fiber. It is also conceivable to raise the pH to increase the solubility of the proteins. This can be achieved, for example, using an alkaline solution such as sodium hydroxide. Another possibility for protein extraction would be extraction using an alkaline solvent such as sodium hydroxide at temperatures < 100°C, preferably between 70°C and 100°C, and / or through the use of enzymes such as Alcalase.

[0029] In a further development, it is conceivable that the extraction agent is selected from an inorganic solvent, such as water, steam, an acid, a base, such as sodium hydroxide, and / or liquefied carbon dioxide, an organic solvent, such as an alcohol, a terpene, a diethyl ether, a vegetable oil, a chlorinated hydrocarbon and / or n-hexane, an enzyme, such as alcalase, a mixture and / or a combination thereof, as described in detail elsewhere. Furthermore, it is conceivable that several extraction agents are used, which are preferably used at different pH values ​​adapted to the extraction agent.

[0030] It is further conceivable that the deodorization in step c) takes place by washing the spent grain with a solvent, wherein the solvent is an inorganic solvent, such as water, an acid, in particular a dilute acid, a base, in particular a dilute base, or an organic solvent, such as an alcohol, a terpene, a diethyl ether, a vegetable oil, a chlorinated hydrocarbon and / or n-hexane, a mixture and / or combination thereof. The deodorization of the spent grain is preferably carried out by washing it with a solvent, such as dilute alkali, for example sodium hydroxide solution 2% to 10% mm, with dilute acid, an organic solvent, an inorganic solvent and / or with pure water. By means of this step, it is possible to optimally adjust the low sensory properties of the filter aid required for liquid filtration.Furthermore, it is conceivable that in step a) and / or after step c), partial or complete drying of the spent grain takes place. Suitable methods and means are known to a person skilled in the art. Furthermore, it is conceivable to use energy and / or heat from renewable energies or waste heat for the partial or complete drying of the spent grain. Partial combustion of the spent grain is also known from the prior art for generating heat for drying and can be used here. Likewise, spent filter aid according to the invention could be burned to generate heat and / or fed into a biogas production process.

[0031] Furthermore, it is conceivable that in step a) and / or before step c) a partial or complete comminution of the spent grain takes place, so that by reducing the particle size the partial or complete drying of the spent grain in step a), the extraction and recovery of the protein fractions in step b), the digestion of fibers in step b) and / or step b1) and / or the effectiveness of the deodorization in step c) is drastically increased, which contributes considerably to cost savings by reducing the necessary energy and / or heat.

[0032] Furthermore, it is conceivable that step d) is followed by step dl): dl) Classifying and / or screening the spent grain crushed in step d).

[0033] It is known to a person skilled in the art that classification and / or screening of the spent grain comminuted in step d) is preferable in order to obtain a filter aid that meets requirements and / or is uniform in the subsequent step e).

[0034] In a further development, it is conceivable that the filter aid obtained in step e) has a particle size of 0 pm to 4000 pm (pm / proportion in %), an average particle size of a maximum of 3 mm, as described in detail elsewhere, a pH value of 3 to 7 (10% / water, 20°C), as described in detail elsewhere, a hemicellulose content of at least 5% by dry weight, a lignin content of at least 2% by dry weight, and / or a water content of 6% to 85%. It has been recognized that the particle size distribution of the filter aid can be monomodal or bimodal.

[0035] The particle size of the filter aid is, gm / portion in %, 0 gm to 4000 gm, preferably at least 10 gm, 20 gm, 30 gm, 40 gm, 50 gm, 100 gm, 150 gm, 200 gm, 250 gm, 300 gm, 350 gm, 400 gm, 450 gm, 500 gm, 550 gm, 600 gm, 650 gm, 700 gm, 750 gm, 800 gm, 850 gm, 900 gm, 950 gm, 1000 gm, 1050 gm, 1100 gm, 1150 gm, 1200 gm, 1250 gm, 1300 gm, 1350 gm, 1400 gm, 1450 gm, 1500 gm,

[0036] 1550gm, 1600gm, 1650gm, 1700gm, 1750gm, 1800gm, 1850gm,

[0037] 1900gm, 1950gm, 2000gm, 2050gm, 2100gm, 2150gm, 2200gm,

[0038] 2250gm, 2300gm, 2350gm, 2400gm, 2450gm, 2500gm, 2550gm,

[0039] 2600gm, 2650gm, 2700gm, 2750gm, 2800gm, 2850gm, 2900gm,

[0040] 2950gm, 3000gm, 3050gm, 3100gm, 3150gm, 3200gm, 3250gm,

[0041] 3300gm, 3350gm, 3400gm, 3450gm, 3500gm, 3550gm, 3600gm,

[0042] 3650gm, 3700gm, 3750gm, 3800gm, 3850gm, 3900gm, 3950gm or 4000gm.

[0043] The hemicellulose content of the filter aid is at least 5%, preferably at least 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or more by dry weight.

[0044] Preferably, the hemicellulose content of the filter aid is 5% to 20% by dry weight, preferably 8% to 20%, more preferably 8% to 15%, and most preferably 8% to 12%.

[0045] The lignin content of the filter aid is at least 2%, preferably at least 3%, 4%, 5%, 6%, 7%, 8%, 9%,

[0046] 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%

[0047] 21%, 22%, 23%, 24%, 25% or more. The lignin content of the filter aid is preferably 2% to 25% by dry weight, preferably 5% to 20%, more preferably 8% to 18%, and most preferably 10% to 18%.

[0048] The water content of the filter aid is 6% to 85%, preferably at least 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%.

[0049] 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%,

[0050] 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%,

[0051] 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%,

[0052] 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%,

[0053] 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%,

[0054] 82%, 83%, 84% or 85%.

[0055] In a further development, the liquid to be filtered in the liquid filtration is wine, sparkling wine, beer, a spirit, a dairy product, juice, in particular vegetable and / or fruit juice, nectar, a soft drink, water, rainwater, wastewater, an oil, a mineral oil, a mixture and / or combination thereof, a raw material thereof and / or an intermediate product, as described in detail elsewhere.

[0056] It is assumed that the definitions and / or the explanations of the above terms apply to all aspects described below in this description, unless otherwise stated.

[0057] According to the invention, a filter aid for liquid filtration is further proposed, preferably produced by the process according to the invention described in detail elsewhere. The filter aid is characterized in that the filter aid has a particle size of 0 pm to 4000 pm (pm / portion in %), an average particle size of maximum 3 mm, a pH value of 3 to 7

[0058] (10% / water, 20°C), a hemicellulose content of at least 5% by dry weight, a lignin content of at least 2% by dry weight, and / or a water content of 6% to 85%. The particle size, mean particle size, pH value, hemicellulose content, lignin content, and water content are described in detail elsewhere. It has been recognized that the particle size distribution of the filter aid can be monomodal or bimodal.

[0059] The filter aid according to the invention is environmentally friendly, harmless from an occupational health perspective and / or in terms of health for humans and / or animals and meets the applicable legal requirements for food additives according to Regulation (EU) No. 231 / 2112.

[0060] Advantageous further developments of the invention, which can be implemented individually or in combination, are presented in the subclaims.

[0061] According to the invention, a filter for liquid filtration is further proposed, which comprises at least one filter layer, wherein the filter layer has at least one filter aid described in detail elsewhere, preferably produced by the method according to the invention described in detail elsewhere, and / or is formed from the filter aid.

[0062] The term "filter" is known to a person skilled in the art and relates to a device for separating solids from a liquid stream. Within the scope of the invention, it has been recognized that the filter has at least one, preferably two, three, four, five, six, seven, eight, nine, ten or more, identically or differently designed filter layers through which the liquid to be filtered is passed. Preferably, the filter layer is compressible and / or briquettable, so that a significant portion of the valuable residual filtrate can be recovered. Preferably, product losses are low, at most 1%, more preferably at most 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%. Within the scope of the invention, it is irrelevant whether the liquid to be filtered is sucked through the filter or pressed through the filter under pressure.

[0063] Furthermore, it has been recognized that the filter layer comprises at least one filter aid described in detail elsewhere and / or is formed from the filter aid.

[0064] Advantageous further developments of the invention, which can be implemented individually or in combination, are presented in the subclaims.

[0065] In a further development, it is conceivable that the filter is a precoat filter, in particular a precoat candle filter, a precoat disc filter, a precoat frame filter or a horizontal filter.

[0066] According to the invention, the use of a filter described in detail elsewhere and / or a filter aid described in detail elsewhere is further proposed for the filtration of wine, sparkling wine, beer, a spirit, a dairy product, juice, in particular vegetable and / or fruit juice, nectar, a soft drink, water, rainwater, wastewater, oil, mineral oil, a mixture and / or combination thereof, a raw material thereof and / or an intermediate product.

[0067] Further details, features, and advantages of the invention will become apparent from the following description of the preferred embodiments in conjunction with the subclaims. The respective features can be implemented individually or in combination with one another. The invention is not limited to the embodiments. The embodiments are illustrated schematically in the figures. The same reference numerals in the individual figures designate identical or functionally identical elements, or elements corresponding to one another in terms of their function.

Claims

Patent claims 1. A process for producing a filter aid for liquid filtration, comprising the following steps: a) providing a spent grain; and b) extracting and recovering the protein fraction from the spent grain; and c) deodorizing the spent grain; and d) comminuting the spent grain; and e) obtaining the filter aid for liquid filtration.

2. Process according to claim 1, wherein in step b) and / or after step b) as step b1) a digestion of the fibers takes place.

3. The process according to claim 1 or 2, wherein the extraction and recovery in step b), the digestion in step b) and / or in step b1) is carried out using an extractant, a temperature in the range of 70°C to 240°C and / or a duration of 5 minutes to 90 minutes.

4. The method according to claim 3, wherein the extraction agent is selected from water, steam, an acid, a base, liquefied carbon dioxide, an alcohol, a terpene, a diethyl ether, a vegetable oil, chlorinated hydrocarbon, n-hexane, an enzyme, a mixture and / or a combination thereof.

5. The process according to any one of claims 1 to 4, wherein the deodorization in step c) is carried out by washing the spent grain with a solvent, wherein the solvent is water, an acid, in particular a dilute acid, a base, in particular a dilute base, an alcohol, a terpene, a diethyl ether, a vegetable oil, a chlorinated hydrocarbon, n-hexane, a mixture and / or combination thereof.

6. Process according to one of claims 1 to 5, wherein in step a) and / or after step c) partial or complete drying of the spent grain takes place.

7. A process according to any one of claims 1 to 6, wherein in step a) and / or before step c) a partial or complete comminution of the spent grain takes place.

8. The method according to any one of claims 1 to 7, wherein after step d) Step dl ) is carried out: dl ) Classifying and / or screening the spent grain crushed in step d).

9. The process according to any one of claims 1 to 8, wherein the filter aid obtained in step e) has a particle size of 0 pm to 4000 pm (pm / proportion in %), an average particle size of at most 3 mm, a pH of 3 to 7 (10% / water, 20°C), a hemicellulose content of at least 5% by dry weight, a lignin content of at least 2% by dry weight and / or a water content of 6% to 85%.

10. The method according to any one of claims 1 to 9, wherein the liquid to be filtered in the liquid filtration is wine, sparkling wine, beer, a spirit, a dairy product, juice, in particular vegetable and / or fruit juice, nectar, a soft drink, water, rainwater, wastewater, an oil, a mineral oil, a mixture and / or combination thereof, a raw material thereof and / or an intermediate product. 1 1. Filter aid for liquid filtration, preferably produced according to one of claims 1 to 10, characterized in that the filter aid has a particle size of 0 pm to 4000 pm (pm / proportion in %), an average particle size of at most 3 mm, a pH value of 3 to 7 (10% / water, 20°C), a hemicellulose content of at least 5% by dry weight, a lignin content of at least 2% by dry weight and / or a water content of 6% to 85%.

12. A filter for liquid filtration comprising at least one filter layer, wherein the filter layer comprises at least one filter aid according to claim 1 1 and / or is formed from the filter aid according to claim 1 1.

13. Filter according to claim 12, wherein the filter is a precoat filter, a precoat candle filter, a precoat disc filter, a precoat frame filter or a horizontal filter.

14. Use of a filter according to claim 12 or 13 and / or a filter aid according to claim 11 for the filtration and / or stabilization of wine, sparkling wine, beer, a spirit, a dairy product, juice, in particular vegetable and / or fruit juice, nectar, a soft drink, water, rainwater, wastewater, oil, mineral oil, a mixture and / or combination thereof, a raw material thereof and / or an intermediate product.

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