Method for producing dairy substitute products

Abstract

The present invention relates to a method for processing raw materials of plant origin and to the use of apparatuses for the solid-liquid separation of suspensions in order to produce extracts, drinks or derived products (yoghurts, creams etc.) also known as "plant-based products" in the agrifood industry. The method comprises at least the following steps: - suspending a material of plant origin; - solid-liquid separation using a plate filter press, comprising the phases of: - filling the filter with the suspension to be filtered; - filtering the suspension and simultaneously forming a porous filter cake; - optionally washing the filter cake in order to recover most of the extract present in the cake; and - discharging the cake; and- homogenising the filtrate. Said method makes it possible to improve the yield in the production of plant milk. In particular, it optimises recovery of the extract and reduces electrical and thermal power consumption.

Description

[0001] Process for producing dairy substitutes

[0002] The present invention relates to a process for producing dairy substitutes from raw materials of plant origin and the use of equipment for the solid-liquid separation of suspensions, to produce extracts, drinks or derived products (yogurts, creams, etc.), also called "plant-based products", in the agri-food industry.

[0003] Introduction

[0004] Dairy substitutes are increasingly popular. In recent years, their consumption has rapidly intensified. They meet consumer needs, whether ethical or health-related, and are part of the growing interest in "vegan" products. They have interesting properties, particularly from an environmental and nutritional point of view, for example for people who are lactose intolerant or allergic to cow's milk. They are particularly rich in fiber and fatty acids. See "Plant-based milk substitutes: Bioactive compounds, conventional and novel processes, bioavailability studies, and health effects" Journal of Functional Foods (2020)-Elsevier; Elif Feyza Aydar, et al.

[0005] Milk substitute drinks include drinks made by suspending plant materials and their extracts in water. The following plant materials are distinguished: nuts: almonds, walnuts, hazelnuts, cashew nuts, macadamia nuts; cereals: barley, wheat, spelt, rice, oats; legumes: soybeans, peas, peanuts; coconut; seeds: sunflower, hemp; tubers: potatoes, cassava, . . .

[0006] The production processes for these dairy substitutes can be improved, particularly for the separation of soluble fibers and macronutrients from insoluble fibers, commonly called draff or "okara". State of the art

[0007] For the production of plant-based milks, the separation of soluble fibers and macronutrients from insoluble fibers is generally carried out using decanter centrifuge technology. The use of centrifugal force has the advantage of being able to clarify suspensions of any type, taking into account the raw material and its pre-treatment. This technique also allows the percentage of dry matter in the filtered product to be set.

[0008] WO 2014 / 123466 describes a process for producing a liquid oat base for use as a milk substitute or food additive. The process comprises the steps of grinding, enzyming, liquid-solid separation, addition of ingredients, heat treatment, homogenization and packaging.

[0009] The liquid-solid separation step is carried out using a decanter; it can be omitted.

[0010] EP 0 731 646 B1 describes a process for preparing a suspension of cereals, in particular oats, which comprises the steps of grinding, suspension in water, optional solid-liquid separation to remove coarse fibrous particles, enzymatic treatment, homogenization, sterilization. The solid-liquid separation step is carried out by centrifugation (Example 2) or decantation (claims).

[0011] EP 2 476 317 describes a process for producing an almond drink. The process comprises the steps of drying the almonds, dry grinding, dispersing the almond paste in an aqueous medium, optional heat treatment and optional packaging. No liquid-solid separation step is described.

[0012] Document DE 2020211101792 U1 describes a process for preparing a fermented plant extract for milk substitute products. The process comprises the steps of liquefaction of the starch contained in a plant material, in particular oats, with the possible addition of enzymes; possible dilution; solid-liquid separation to remove insoluble components; fermentation; then filtration to remove yeasts. In the exemplary embodiments, the solid-liquid separation is carried out by centrifugal decantation.

[0013] Centrifugal decanters are efficient in terms of solid-liquid separation, they allow the separation of particles based on their density difference under the effect of centrifugal force at speeds ranging from 1500 to 10000 g (gravitational force). This operating principle results in significant electricity consumption. On the other hand, losses in "extract", particularly in the solid residue ("okara") are high. Indeed, at the outlet of the decanter, the okara has a humidity of around 75%. This percentage of humidity of the okara is therefore made up of the "extract", which ends up in a by-product and is not recovered. This is a significant loss of efficiency in the overall manufacturing process.

[0014] Since separation in a decanter centrifuge is continuous, it is not possible to wash the solid residue during the separation cycle in the same machine. Washing is possible if the solid residue from the separation is resuspended in water and then subjected to a second separation by centrifugal decantation. This process involves using two decanters placed in series, or reusing the decanter intended for separation for a washing cycle. Both options are expensive and not attractive from the point of view of cycle time and efficiency.

[0015] In the field of filtration, there are different types of filters, including so-called "plate" filter presses.

[0016] The applicant supplies industrial equipment, in particular a filter press for filtering brewery or distillery mash and separating the spent grain from the wort; the clarified wort is used for the production of beer, alcohol or extract.

[0017] Tray filter presses consist of a plurality of vertical trays joined together by their peripheral frame. A filter support, generally a flexible cloth, is stretched over each tray so as to delimit, on either side of the filter support: a filtration chamber, and a filtrate collection chamber. The filter support is fixed to the tray. As filtration progresses, the suspension to be filtered is introduced into the filtration chamber, a filter cake forms on the filter support and the must is collected in the collection chamber and then flows through the collection channels.

[0018] Each tray may comprise an elastomeric membrane which allows the compression of the filter cake by introducing a compression fluid. These filters are also called thin-film membrane filters. Such a filter is for example described in documents EP 2 248 571 A1 and EP 3 138 620 B1. The present invention aims to provide a method for treating raw materials of plant origin for the production of a base for producing extracts, drinks or derived products (yogurts, creams, etc.), also called "plant-based products", in the agri-food industry.

[0019] It has been discovered that it is possible to improve the efficiency of these processes by using a filter press, particularly a membrane filter, for the solid-liquid separation step following the suspension and possible hydrolysis step.

[0020] Another goal is to propose a process with reduced consumption of electrical and thermal energy.

[0021] The subject of the present invention is a process for producing dairy product substitutes which comprises at least the following steps:

[0022] - suspension of a material of plant origin containing compounds to be extracted;

[0023] - solid-liquid separation using a plate filter press which comprises at least filtration chambers and filter supports, said solid-liquid separation step comprising the phases of: o filling the filter with the suspension to be filtered; o filtration of the suspension and concomitant formation of porous filter cakes (consisting at least in part of the insoluble elements contained in the suspension); o possibly washing the filter cakes, in order to recover the majority of the extract present in the cakes; o de-bagging;

[0024] - homogenization of the filtrate.

[0025] Homogenization of the filtrate allows obtaining a stable colloidal drink.

[0026] Filter cakes consist mainly of the insoluble matter contained in the starting plant material. If the plant material contains little insoluble matter, additional insoluble matter can be added to the suspension before filtration to aid in the formation of porous filter cakes.

[0027] Raw materials of plant origin are chosen from nuts such as almonds, walnuts, hazelnuts, cashews, macadamia nuts; cereals such as barley, wheat, spelt, rice, oats; legumes such as soybeans; peanuts; coconuts; seeds such as sunflower, hemp; tubers such as potato and cassava. These materials mostly contain starch.

[0028] During the suspension stage, particularly in water, macromolecules such as starch and proteins contained in the starting plant material are solubilized or even hydrolyzed into simpler molecules (sugars, dextrins, amino acids, low molecular weight proteins, soluble beta-glucans, etc.). It is preferable that there is practically no residual starch left in the suspension to be filtered, otherwise the cakes and filter media could become clogged.

[0029] Advantageously, the “water / raw material” weight ratio is between 0.5 and 6, preferably between 1.5 and 5, and more preferably between 2 and 4. This ratio may be adapted depending on the raw materials used.

[0030] To carry out the hydrolysis, the suspension is heated to different temperature levels with or without the addition of enzymes. The suspension can be heated indirectly or directly by injecting steam into the suspension.

[0031] Cooling can be interspersed between the heating stages.

[0032] The temperature and pH must be adapted according to the raw materials used, the final composition of the desired product and the type of enzymes used. Other additives can be added during suspension (calcium, acid or base to modify the pH, antioxidant etc.)

[0033] At the end of hydrolysis, the solid-liquid separation step aims to separate soluble fibers and macronutrients from insoluble fibers (commonly called “okara”).

[0034] When the solid-liquid separation step includes a filter cake washing phase, this is carried out by pumping water which percolates through the filter cakes. The temperature of the washing water is preferably between 60 and 95°C, more preferably between 70 and 85°C.

[0035] Preferably, the filter press comprises elastomeric membranes.

[0036] In this case, the method of the invention comprises at least the following steps:

[0037] - suspension of a material of plant origin comprising compounds to be extracted; solid-liquid separation using a membrane plate filter press which comprises at least filtration chambers and a filter support, said solid-liquid separation step comprising the phases of: o filling the filter with the suspension to be filtered; o filtration of the suspension and concomitant formation of porous filter cakes (consisting at least in part of the insoluble elements contained in the suspension) on the filter support; o pre-compression of the filter cakes in order to recover the maximum amount of extract and homogenize the cakes; o washing of the filter cakes, in order to recover the majority of the extract present in the cakes; o compression in order to reduce the moisture content of the cakes; o de-batching; homogenization of the filtrate.

[0038] Pre-compression of the cakes is achieved by inflating the membranes with a compression fluid. This can be water or air.

[0039] In particular, a pre-treatment is carried out before suspension. This pre-treatment may include a step of partial or total removal of the envelopes of the raw material of plant origin; it may include soaking and / or heat treatment by steam or indirect heating. The soaking may be carried out in water at room temperature or in hot water. The composition of the soaking water may be adapted, in particular it may include additives, for example to adjust the pH.

[0040] Depending on the raw materials used, for reasons of process or organoleptic qualities of the finished product, they may be soaked, bleached, de-oiled, before grinding.

[0041] According to a particular embodiment of the invention where the material consists of whole cereal grains, the removal of the husks involves the subtraction of 2 to 30% by weight of the raw material (preferably 5 to 20%).

[0042] The different pre-treatment steps can be interchanged.

[0043] Depending on the raw material used, pre-treatment may include grinding. This can be wet or dry grinding. Mills can be impact, colloidal, or disc. Double grinding (dry and wet) is also possible.

[0044] The grinding advantageously makes it possible to obtain a particle size of between 50 pm and 1800 pm, preferably between 100 pm and 1000 pm, preferably between 125 pm and 500 pm. The method according to the invention may also include one or more post-treatments.

[0045] Once the solid-liquid separation has been carried out, the “juice” or “must” or “filtrate” can be cooled, to then continue the downstream process steps.

[0046] For the production of a “vegetable milk” for example, it may undergo the stages of formulation, homogenization and heat treatment (UHT) for sterilization, before packaging. Additives are potentially added to provide consistency, vitamins, a color effect, texture, taste: salts, oil, flavorings, etc.

[0047] Homogenization is an important step that aims to improve the physical stability of the final product. It is generally carried out by agitation with rotor / stator mixers producing high shear, or with so-called pressure homogenizers (low, high, ultra-high pressure piston pumps). The aim of this operation is to reduce the particle size and improve the stability of the final product as well as its whiteness.

[0048] In particular, stirring can be carried out at a speed between 2000 and 4000 rpm, for a period of 5 to 15 min.

[0049] The subject of the invention is also the use of a filter press comprising a plurality of filtration chambers and a plurality of filter supports, for the solid-liquid separation of a suspension of a raw material of plant origin comprising compounds to be extracted.

[0050] Other advantageous modes are described in the subclaims.

[0051] The present invention is particularly suitable for processes using thin-film filters, i.e. those with a filter cake layer of between 20 and 100 mm, such as the Meura 2001 filter press.

[0052] EXAMPLE OF EMBODIMENT The present invention is now described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 represents a sectional view of two support plates; Figs. 2 to 9 represent a sectional view of a filter press, comprising five support plates, each fig. representing a different stage of the solid-liquid separation process.

[0053] In Fig. 2, the filter is empty.

[0054] Fig. 3 illustrates the filling step.

[0055] Fig. 4 illustrates the filtration step.

[0056] Fig. 5 illustrates the pre-compression step.

[0057] Fig. 6 illustrates the start of washing.

[0058] Fig. 7 illustrates the washing step.

[0059] Fig. 8 illustrates the final compression stage.

[0060] Fig. 9 illustrates the stripping stage.

[0061] Fig. 1 illustrates two support trays 1 assembled by their peripheral frame. Each tray 1 has on one side a filter cloth 2 and on the other side a flexible elastomer membrane 3. This forms a succession of compression chambers 4, filtration chambers 5 and collection chambers 6. The trays may have one or more central bosses (not shown).

[0062] The side of the tray facing the filter cloth may have filtrate drainage pads.

[0063] The filtration chamber 5 is connected to a lower inlet or supply channel 7. The collection chamber is connected to a lower 8 and upper 9 collection channel. The compression chamber 4 is connected to a compression fluid supply channel 10.

[0064] EXAMPLE 1

[0065] This example details a method of producing oat milk using raw oats with some of the grain hulls removed.

[0066] Pre-treatment of raw materials

[0067] Oat grains have unique properties in terms of composition and structure; they require different processes compared to other cereal grains. For the production of oat milk, whole oat grains are usually hulled, as their hulls are indigestible and undesirable for organoleptic reasons in the finished product.

[0068] In the context of the present invention, however, it is necessary to form a porous cake to ensure good filtration efficiency. In addition, washing of this filter cake can be carried out, in order to recover a maximum of extract.

[0069] Complete hulling of oat grains would not leave enough insoluble compounds for the formation of such a filter cake. The inventors noticed that if the oat grain hulls are completely removed, filtration can cause clogging problems.

[0070] In order to establish a compromise between the filterability of the suspension to be filtered and the organoleptic quality of the product, the applicant carried out a treatment of the oat grains aimed at partial elimination of the husks.

[0071] There are various techniques for separating some or all of the hulls, either before or after grinding the whole grains. In this example, the inventors chose to remove some of the hull fraction after grinding the oat grains.

[0072] Grinding

[0073] The pilot mill used is a hammer mill equipped with a 9.2 kW motor. The motor drives four rows of six hammers. A forced ventilation system allows the fine particles produced during grinding to be carried away and trapped on fabric filter sleeves to avoid the risk of explosion within the mill.

[0074] The screen installed for grinding has perforations of 3 mm diameter.

[0075] After grinding, the entire grind is passed through a vibrating sieve (Russell Finex EcoSeparator, 2 mm sieve, 30”) to separate part of the straw (husking). The coarsest fraction retained on the sieve, mainly consisting of husks, is separated from the rest of the grind and represents 17% of the total mass of the grains.

[0076] Suspension (Mashing / Hydration)

[0077] The resulting ground material (partially freed from the husks) is then conveyed by a screw to a hydrator for mixing with water. The temperature of the mashing water is set at 55°C, and the total amount of water is set to obtain a final water ratio of 2.5 liters of water per kg of ground material. This water / ground material ratio, reduced compared to oat milk production according to the state of the art, is inherent to the use of a plate filter press. Indeed, a filtration cycle on a filter press advantageously includes a washing step for recovering the extract contained in the filter cakes. The final concentration of the juice after solid-liquid separation therefore includes the quantities of water introduced at the suspension step and at the washing step during the filtration cycle. The hydration ratio is defined on this basis.

[0078] Working with more concentrated suspensions also reduces the thermal energy consumption of the steps upstream of liquid-solid separation. In this example, 42 kg of partially hulled raw oats were milled and mixed with 105 L of water at 55°C, i.e. a ratio of 2.5 L of water / kg of oat meal.

[0079] It is estimated that the thermal energy required for heating and cooling this suspension during hydrolysis is approximately 30% lower than that of a suspension with a ratio of approximately 4-5L of water per kg of oat flour.

[0080] After correcting the pH to 6 with phosphoric acid and adding an alpha-amylase promoting the conversion of starch into simple sugars, the suspension obtained is subjected to a hydrolysis diagram optimized for the action of these enzymes:

[0081] 30 min at 75°C rising to 85°C.

[0082] This is a simple hydrolysis diagram, other recipes involving other enzymes and other temperature levels can of course be considered depending on the desired composition of the finished product (sugars, proteins, beta-glucans, etc.)

[0083] Heating with a temperature increase of 1°C / min and temperature maintenance at the various stages are ensured by direct injection of low-pressure steam (Meura “Aflosjet ®” system) into the product.

[0084] We then obtain a suspension of hydrolyzed oats.

[0085] Solid-liquid separation

[0086] The suspension is then filtered using a four-chamber “Meura 2001 Hybrid Micro” filter with a total nominal capacity of 44 kg of malt equivalent (11 kg per chamber). The filtration cycle follows the following sequence of steps: Filling (fig. 3): the suspension is sent to the filter using a centrifugal pump operating at constant speed, through the feed channels 7, so as to fill the filtration chambers 5, in 2 to 4 minutes.

[0087] Filtration (fig. 4): the rest of the suspension is transferred to the filter, the filtering effect being ensured by the progressive formation of cakes 11 made up of insoluble matter in the suspension on the filter cloths 2. The suspension is first sent at a constant flow rate (7.5 L / min) until reaching the regulation pressure (450 mbar) and then maintaining this pressure within the filter. The total volume of suspension is thus transferred in 21 minutes to the filter, and 7 IL of dense juice at 16.9°Plato are collected by the collection channels 8 and 9. One Plato unit represents the mass percentage of extract in the filtrate.

[0088] Precompression (fig. 5): air (450 mbar) is injected for 5 minutes, through the supply channels 10 into the compression chambers 4 of each of the filter elements so as to precompress the previously formed filter cakes 11. This step makes it possible to recover an additional 8L of dense juice and to homogenize the porosity of the cakes for effective washing.

[0089] Washing (fig. 6 and 7): 65L of water at 85°C are then sent in 61 minutes to the filtration chambers 5 and pass through the filter cakes 11 to recover a maximum of the extract they contain. During this stage, the density of the juice leaving the filter gradually decreases as the water carries away the extract contained in the filter cakes to reach 1 to 2°P at the end of washing.

[0090] Final compression (fig. 8): air is again sent into the compression chambers 4 (700 mbar) for 5 minutes in order to compress the cakes 11 and thus recover a maximum of extract while drying them to facilitate their de-scraping. In total, 148 L of oat juice at 14.0°P will have been harvested in 11134.

[0091] De-basting (fig. 9): at the end of the cycle, the filter is opened and the filter cakes (okara) at 75% humidity are removed. The essential difference between this type of separation and separation by centrifugal decanter or high-pressure filter press without washing is that the extract present in the filter cake (okara) is recovered and forms an integral part of the final product.

[0092] The filtration and pre-compression steps will have allowed 79L of juice to be collected at 16.9°P, which represents 65% of the total extract recovered during the filtration cycle. The washing and final compression steps will have allowed 35% additional extract to be recovered.

[0093] Post-processing (Formulation and homogenization)

[0094] To obtain oat "milk", the juice collected at the filter outlet is cooled, then diluted by adding water to obtain the desired final concentration, and transferred to a homogenization tank.

[0095] Sunflower oil (3.3 mL / L of juice) and a 20% NaCl solution (14 mL / kg of ground material) were added, and the mixture was homogenized. Stirring the mixture with a rotor / stator rotating at 3000 rpm (Mixturall, Boccard) for 10 minutes resulted in a stable emulsion.

[0096] EXAMPLE 2

[0097] This 2 emeexample details a method for producing oat milk from raw oats that have undergone pretreatment consisting of partial hulling followed by heat treatment with steam.

[0098] Pre-treatment of raw materials

[0099] The pretreatment of raw materials aims to improve the organoleptic qualities of the finished product and is carried out here in 2 distinct interchangeable stages:

[0100] 1. Partial separation of the straw from the grain, ensuring that a certain proportion of straw is retained, which is necessary for the formation of the filter cake during the solid-liquid separation stage.

[0101] 2. Heat treatment of grains

[0102] For the first stage, oats have the particularity of having an envelope that is easily separated from the endosperm, which is separated from the grain using an impact huller before being eliminated by an aerodynamic separation system. This allows, starting from 60 kg of raw oats, to eliminate 12 kg of straw, i.e. 20% of the total mass of the grains.

[0103] Then, during the 2 eme step, the remaining fraction, mainly consisting of naked grains, will undergo a heat treatment. Indeed, given its high lipid content, oats are particularly sensitive to oxidation which can make the final product rancid if no heat treatment is applied beforehand. In this example, the treatment applied is a 20-minute steam contact.

[0104] Grinding / hydration

[0105] In this 2 emeFor example, wet grinding was used. The pilot mill used is a hammer mill equipped with an 18.5 kW motor. The motor drives four rows of eleven hammers. The installed screen has 3 mm diameter perforations. A water / grain mixture is produced in the grinding chamber.

[0106] The grain feed rate is set at 2.4 kg / min and the water flow rate at 4.8 L / min to achieve an instant mashing ratio of 2 L / kg. The grains, still warm from the steam treatment, are milled and mashed simultaneously with mashing water at 25°C, so that the final temperature reaches approximately 55°C. The mashing water also contains the additives (KMS and Calcium) and enzymes (alpha-amylase 10 kg / T of oats) necessary for mashing and hydrolysis.

[0107] A certain volume of rinsing water is used at the end of milling to flush residual particles out of the milling chamber. This volume of water is set to achieve a total mashing ratio of 2.3 L / kg. Thus, 43.7 kg of pre-treated oats were mixed with 100.6 L of water.

[0108] After grinding, the suspension thus obtained is continuously transported by pumping from a buffer tank to the hydrolysis tank.

[0109] Hydrolysis

[0110] After correcting the pH to 6 with phosphoric acid, the suspension, also containing the enzymes promoting the conversion of starch into simple sugars, is subjected to a hydrolysis diagram optimized for the action of these enzymes:

[0111] Initial temperature at 55°C

[0112] 30 min at 75°C rising to 85°C.

[0113] Heating with a temperature increase of 1°C / min and temperature maintenance at the various stages are ensured by direct injection of low-pressure steam (Meura “Aflosjet ®” system) into the product.

[0114] A suspension of hydrolyzed oats is then obtained. A control test with an iodine solution (0.02 N solution to be placed in contact with the suspension) confirms (neutral coloration) or not (black / purple coloration) the conversion of the starch.

[0115] Solid-liquid separation

[0116] The suspension is then filtered using a four-chamber “Meura 2001 Hybrid Micro” filter with a total nominal capacity of 44 kg of malt equivalent (11 kg per chamber). The filtration cycle follows the following sequence of steps:

[0117] Filling (fig. 3): the suspension is sent to the filter using a centrifugal pump, through the feed channels 7, so as to fill the filtration chambers 5, in 2 to 4 minutes.

[0118] Filtration (fig. 4): the rest of the suspension is transferred to the filter. The total volume of suspension is transferred to the filter in 9 minutes. The pressure is gradually built up as the cake forms to reach 0.4 to 0.5 bar. 70L of dense juice at 18.8 °Plato are collected through collection channels 8 and 9.

[0119] Precompression (fig. 5): air injection (350 mbar), through the supply channels

[0120] 10 in the compression chambers 4 of each of the filter elements allows to recover an additional 33 L of dense juice and to homogenize the porosity of the cakes for an efficient washing. This step lasts 5 min.

[0121] Washing (fig. 6 and 7): 38L of water at 85°C are then sent in 14 minutes into the filtration chambers 5 and pass through the filter cakes 11 to recover a maximum of the extract they contain.

[0122] Final compression (fig. 8): air is again sent into compression chambers 4 (700 mbar) for 8 minutes in order to compress the cakes

[0123] 11 and thus recover a maximum of extract while drying them to facilitate their de-scraping. Compression allows 25 L of additional juice to be recovered.

[0124] In total, 168 L of "oat juice" at 14.6°P will have been harvested in 38 minutes. The turbidity of the juice is measured at 748 FAU and the quantity of sediment 2g / 100g of juice. De-sludge (fig. 9): at the end of the cycle, the filter is opened and the filter cakes (okara) at 58% humidity are removed.

[0125] Post-processing (Formulation - homogenization)

[0126] To obtain oat "milk", the juice collected at the filter outlet is cooled using a plate exchanger, then diluted by adding water to obtain the desired final concentration of 13°P, and transferred to a homogenization tank.

[0127] Sunflower oil (10 mL / L of juice) and a 20% NaCl solution (3.7 mL / L of juice) were added, and the mixture was homogenized. Stirring the mixture with a rotor / stator rotating at 3000 rpm (Mixturall, Boccard) for 10 minutes resulted in a stable emulsion.

[0128] Benefits

[0129] The advantages of using the thin-film membrane filter are: producing clarified juice in an optimized cycle time; recovering most of the extract from the hydrolyzed suspension, thanks to the filter cake washing step; producing okara with a reduced moisture content, which reduces the risk of contamination, transport and storage costs.

[0130] The invention also made it possible to optimize the efficiency of the separation cycle compared to prior art technologies. In particular, the washing step makes it possible to recover almost all of the extract impregnated in the filter cakes (spent grains or okara).

[0131] The invention also makes it possible to reduce the electrical and thermal consumption of the process. When part of the water to be incorporated into the product to reach the final concentration is added at the washing stage, the operations upstream of the filter (hydrolysis) are carried out at a higher concentration (reduced water / kg material ratios); this results in smaller volumes of suspensions to be heated in the tanks before filtration.

[0132] Another advantage is that the filter press does not require high-power electric motors like decanter centrifuges.

Claims

DEMANDS 1. A process for producing dairy substitute products that includes at least the following steps: - suspension of a material of plant origin comprising compounds to be extracted solid-liquid separation using a plate filter press which includes at least one succession of filtration chambers (5) and filter supports (2), said solid-liquid separation step comprising the phases of: o filling the filter with the suspension to be filtered; o filtration of the suspension and concomitant formation of porous filter cakes (11) on the filter supports (2) o decake removal; - homogenization of the filtrate.

2. A process according to the preceding claim, characterized in that it comprises a pre-treatment step of the raw material, prior to the suspension step.

3. A process according to the preceding claim, characterized in that the pre-treatment comprises a heat treatment step of the raw material.

4. A process according to the preceding claim, characterized in that the pre-treatment comprises a step of soaking the raw material.

5. A process according to any one of claims 2 to 4, characterized in that the pretreatment comprises grinding of raw materials of vegetable origin.

6. A process according to any one of claims 2 to 5, characterized in that the pretreatment comprises a step of dehulling the raw material removing 2 to 30% by weight of it. A process according to the preceding claim, characterized in that the mashing water is introduced in a water / plant matter weight ratio of between 0.5 and 6. A process according to any one of the preceding claims, characterized in that, at the suspension stage, the suspension is heated to several temperature levels, with or without the addition of enzymes. A process according to any one of the preceding claims, characterized in that the solid-liquid separation stage is carried out at a pressure below 2 bar, preferably below 1 bar, and even more preferably between 0.3 and 0.8 bar. A process according to any one of the preceding claims, characterized in that the solid-liquid separation stage comprises a washing phase of the filter cakes (11).A method according to any one of the preceding claims, characterized in that the filter press comprises elastomeric membranes (3); at the end of filtration, the membranes (3) are inflated with a fluid to exert compression on the filter cakes (11). A method according to the preceding claim, characterized in that at the end of washing, the membranes (3) are inflated with a fluid to exert compression on the filter cakes (11). A method according to any one of the preceding claims, characterized in that the homogenization step comprises high-shear agitation. A method according to any one of the preceding claims, characterized in that the homogenization step is carried out in a pressure homogenizer. A method according to any one of the preceding claims, characterized in that it comprises a formulation step. A process according to any one of the preceding claims, characterized in that the plant-based materials are selected from nuts such as almonds, walnuts, hazelnuts, cashews, macadamia nuts; cereals such as barley, wheat, spelt, rice, oats; legumes such as soybeans, peanuts; coconuts; seeds such as sunflower, hemp; and tubers such as potatoes, cassava. The use of a filter press comprising a series of filtration chambers (5) and filter media (2) for the solid-liquid separation of a suspension of a plant-based raw material containing compounds to be extracted for the production of a dairy substitute, characterized in that the separation comprises the following phases: - filling of the filtration chambers (5); - Filtration of the suspension and concomitant formation of porous filter cakes (11) on the filter media (2); - washing of filter cakes (11); - cake removal. Use according to the preceding claim, characterized in that the separation comprises at least one phase of compression of the filter cakes (11). Use according to the preceding claim, characterized in that a compression phase is carried out before washing the cakes (11). Use according to any one of claims 18 and 19, characterized in that a compression phase is carried out after washing the cakes (11).

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