How dairy alternatives are made

Abstract

A process for the production of dairy substitutes. The invention relates to a method for the processing of raw materials of plant origin to produce extracts, beverages or derived products (yogurt, cream, etc.), also called "plant-based products" in the agri-food industry, and to the use of an apparatus for solid-liquid separation of suspensions. The method comprises at least the steps of suspending the raw materials of plant origin and solid-liquid separation using a plate filter press, including filling the filter with the suspension to be filtered, filtering the suspension while forming a porous filter cake, optionally sparging the filter cake to recover most of the extract contained in the cake, and discharging the cake, and homogenizing the filtrate. This method improves the production yield of milk of plant origin. In particular, it optimizes the recovery of the extract and allows a reduction in the consumption of electrical and thermal energy.

Description

[Technical field]

[0001] The present invention relates to a method for producing dairy substitutes from raw materials of plant origin and to the use of an apparatus for solid-liquid separation of suspensions, for producing extracts, beverages or derived products (yoghurt, cream, etc.), also called "plant-based products" in the agri-food industry. [Background technology]

[0002] (Introduction) Dairy alternatives are becoming more and more popular. In recent years, the consumption of dairy alternatives has increased rapidly. They respond to consumer needs, whether ethical or health-related, and are also part of the growing interest in "vegan" products. Dairy alternatives have interesting properties from an environmental and nutritional point of view, especially for people with lactose intolerance or milk allergies. In particular, dairy alternatives are rich in dietary fiber and fatty acids. See the literature "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.

[0003] Alternatives to milk include beverages made by suspending plant ingredients or their extracts in water. These plant ingredients include: - Nuts: almonds, walnuts, hazelnuts, cashews, macadamia nuts -Cereals: barley, wheat, spelt, rice, oats -Legumes: soybeans, peas, peanuts -coconut -Seeds: sunflower, hemp -Tubers: potatoes, cassava, …

[0004] The manufacturing processes for these dairy alternatives can be specifically adapted to separate soluble and macronutrient fibres from insoluble fibre (commonly known as spent grains, or "okara").

[0005] (State of the art) When producing plant-based milks, the separation of soluble fibre and macronutrients from insoluble fibre is usually achieved using the decanter centrifuge technique. The use of centrifugal force has the advantage that it is possible to clarify any type of suspension, regardless of the raw material or its pretreatment. This technique also makes it possible to set the percentage of dry matter in the filtered product.

[0006] WO 2014 / 123466 describes a method for producing a liquid oat base for use as a milk substitute or food additive. The method includes grinding, enzyme treatment, solid-liquid separation, ingredient addition, heat treatment, homogenization, and packaging. The solid-liquid separation step is carried out using a decanter, but can be omitted.

[0007] EP 0731646 describes a method for preparing a suspension of cereals, in particular oats. The method comprises the steps of grinding, suspension in water, possible solid-liquid separation to remove coarse fibrous particles, enzymatic treatment, homogenization and pasteurization. The solid-liquid separation step is carried out by centrifugation (example 2) or decantation (claims).

[0008] EP 2476317 describes a method for producing an almond beverage. The method includes the steps of drying almonds, dry grinding, dispersing the almond paste in an aqueous medium, possible heat treatment, and optional packaging. No solid-liquid separation step is described.

[0009] German Utility Model No. 2020211101792 describes a method for preparing a fermented plant extract for milk substitutes. The method comprises the steps of liquefying the starch contained in the plant material, in particular oats, possibly with the addition of enzymes, a possible dilution step, a solid-liquid separation step to remove insoluble components, a fermentation step, and then a filtration step to remove yeast. In a realization, the solid-liquid separation is achieved by decantation with a centrifuge.

[0010] Centrifugal decanters are efficient in terms of solid-liquid separation, allowing separation based on density differences of particles under the influence of centrifugal forces at speeds of 1500-10000 g (gravity). This principle of operation results in high power consumption. On the other hand, losses of "extracts" are high, especially in the solid residue ("okara"). In fact, at the outlet of the decanter, the moisture content of the okara is about 75%. This percentage of moisture in the okara is therefore comprised of "extracts" that are included in the by-products and are not recovered. This is a significant loss of yield in the entire production process.

[0011] Since separation in a decanter centrifuge is a continuous mode, it is not possible to wash the solid residue during the separation cycle in the same equipment. Washing is possible if the solid residue after separation is resuspended in water and then separated a second time by decanter centrifugation. This method involves the use of two decanters in series or the reuse of the separation decanter for the washing cycle. Both options are expensive and unattractive in terms of cycle time and yield.

[0012] In the field of filtration, there are various types of filters, including the so-called "plate filter presses".

[0013] The applicant supplies industrial equipment including a filter press for filtering the brewer's or distiller's mash and separating spent grains from the wort. The clarified wort is used to produce beer, alcohol or extracts.

[0014] Plate filter presses consist of multiple vertical plates assembled together by their peripheral frames. A filter medium (usually a flexible fabric) is stretched on each plate on either side of the filter medium support, separating the filtration chamber from the collection chamber. The filter medium is attached to the plate. As the filtration proceeds, the suspension to be filtered is introduced into the filtration chamber, a filter cake is formed on the filter medium, and the filtered liquid (filtrate) is collected in the collection chamber and flows through the collection channel.

[0015] Each plate may have an elastomeric membrane that allows the compression of the filter cake by the introduction of a compressed fluid. The filters are also called thin bed filters. Such filters are described, for example, in EP 2 248 571 A1 and EP 3 138 620 A1. Summary of the Invention

[0016] The object of the present invention is to provide a method for the processing of raw materials of plant origin in order to produce a base for the production of extracts, beverages or derived products (yoghurt, cream, etc.), also called "plant-based products" in the food industry.

[0017] It has been found that the performance of these processes can be improved by using filter presses, in particular membrane filters, for the solid-liquid separation step following the suspension and subsequent hydrolysis step.

[0018] Another object is to provide a method which consumes less electrical and thermal energy.

[0019] The present invention relates to a method for producing a dairy substitute, comprising the steps of: at least, - suspending a raw material of plant origin containing the compound to be extracted; - a solid-liquid separation step by a plate filter press comprising at least a filtration chamber and a filter medium, - filling the filter with the suspension to be filtered, - filtering the suspension and forming a porous filter cake (comprised of at least the insoluble components of the suspension) as the suspension is filtered; washing the filter cake in order to recover most of the extractable matter contained therein; and A solid-liquid separation step, comprising a discharge step; - homogenizing the filtrate; Includes.

[0020] The filtrate is homogenized to obtain a stable colloidal beverage.

[0021] The filter cake is primarily made up of insoluble material contained in the starting plant material. If the plant material contains low amounts of insoluble material, additional insoluble material can be added to the suspension prior to filtration to aid in the formation of a porous filter cake.

[0022] The raw materials of plant origin are selected from nuts (e.g. almonds, walnuts, hazelnuts, cashews, macadamia nuts), cereals (e.g. barley, wheat, spelt, rice, oats), legumes (e.g. soybean, peanuts), coconuts, seeds (e.g. sunflower, hemp), tubers (e.g. potato, cassava). Most of these raw materials contain starch.

[0023] During the suspension stage, particularly in water, macromolecules such as starch and proteins contained in the starting plant material are solubilized, i.e. hydrolyzed, into simple molecules (sugars, dextrins, amino acids, low molecular weight proteins, soluble β-glucans, etc.) It is preferable that little residual starch remains in the suspension to be filtered, otherwise the filter cake and filter media may become clogged.

[0024] Advantageously, the weight ratio of water to raw materials is between 0.5 and 6, preferably between 1.5 and 5, and even more preferably between 2 and 4. This ratio can vary depending on the raw materials used.

[0025] To carry out the hydrolysis, the suspension is heated to various temperature levels, with or without the addition of enzymes. The suspension can be heated indirectly or directly by injecting steam into the suspension.

[0026] Cooling steps can be sandwiched between heating rests.

[0027] The temperature and pH must be adapted according to the raw materials used, the final composition of the desired product, and the type of enzyme used. Other additives can also be added during suspension (calcium, acids or bases to adjust the pH, antioxidants, etc.).

[0028] The solid-liquid separation step carried out at the end of hydrolysis aims to separate the soluble fiber and macronutrients from the insoluble fiber (commonly known as "okara").

[0029] When the solid-liquid separation step includes sparging the filter cake, this is carried out by pumping the water that permeates the filter cake. The temperature of the sparging water is preferably 60 to 95°C, more preferably 70 to 85°C.

[0030] Preferably, the filter press has an elastomeric membrane.

[0031] In this case, the method of the invention comprises: at least, - suspending a raw material of plant origin containing the compound to be extracted; - a solid-liquid separation step by a membrane plate filter press comprising at least a filtration chamber and a filter medium, filling the filter with the filtration suspension, - filtering the suspension and forming a porous filter cake on the filter medium (comprising at least a portion of the insoluble components of the suspension); pre-compressing the filter cake in order to recover a maximum amount of extract and to homogenize the filter cake; sparging the filter cake to recover most of the extractables contained therein; and A solid-liquid separation step, comprising a discharge step; - homogenizing the filtrate; Includes.

[0032] The pre-compression of the filter cake is performed by expanding the membrane with a compressed fluid, which may be water or air.

[0033] In particular, a pretreatment is carried out before the suspension. This pretreatment may include a step of partial or complete removal of the outer skin of the plant-derived raw material and may include soaking and / or heat treatment by steam or indirect heating. Soaking may be carried out in water at room temperature or in hot water. The composition of the soaking water may be adjusted, in particular the soaking water may contain additives, for example to adjust the pH.

[0034] Depending on the raw materials used, for process reasons or for the organoleptic qualities of the final product, the raw materials may be quenched, bleached or de-oiled before grinding.

[0035] According to a particular embodiment of the invention, in which the raw material consists of whole cereal grains, the removal of the hulls is accompanied by a weight reduction of 2 to 30% (preferably 5 to 20%) by weight of the raw material.

[0036] The various pre-processing steps can be interchanged.

[0037] Depending on the raw materials used, pretreatment may include grinding. Grinding may be wet or dry grinding. The grinding machine (mill) may be an impact mill, a colloid mill or a disk mill. Double grinding (dry and wet) is also possible.

[0038] Grinding is advantageous for obtaining particle sizes of 50 μm to 1800 μm, preferably 100 μm to 1000 μm, more preferably 125 μm to 500 μm.

[0039] The method according to the invention may also include one or more post-treatment steps.

[0040] Once solid-liquid separation is complete, the "juice" or "wort" or "filtrate" may be cooled and then processed downstream.

[0041] For example, in the production of "plant-based milk", the liquid may undergo blending, homogenization, and pasteurization by heat treatment (UHT) before packaging. Additives may be added to provide consistency, vitamins, color benefits, texture, taste (salt, oil, flavors, etc.).

[0042] Homogenization is an important step aimed at improving the physical stability of the final product. It is generally carried out by stirring with rotor / stator mixers generating high shear forces or so-called pressure homogenizers (low-pressure, high-pressure and extra-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.

[0043] In particular, stirring can be carried out at a speed of 2000 to 4000 rpm for 5 to 15 minutes.

[0044] The subject of the present invention is also the use of a filter press comprising a plurality of filtration chambers and a plurality of filter media, for the solid-liquid separation of a suspension of raw material of plant origin containing compounds to be extracted.

[0045] Further advantageous configurations are set forth in the dependent claims.

[0046] The present invention is particularly suitable for processes using thin bed filters, ie filters having a filter cake layer of between 20 mm and 100 mm, such as a Meura 2001 filter press. [Brief description of the drawings]

[0047] The invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0048] [Figure 1] FIG. 1 shows a cross-sectional view of two support plates. [Diagram 2] Figures 2-9 show cross-sectional views of a filter press with five support plates, each representing a different step in the solid-liquid separation process. In Figure 2 the filter is empty. [Diagram 3] Figures 2-9 show cross-sectional views of a filter press with five support plates, each representing a different step in the solid-liquid separation process. Figure 3 shows the filling step. [Figure 4] Figures 2-9 show cross-sectional views of a filter press with five support plates, each representing a different step in the solid-liquid separation process. Figure 4 shows the filtration step. [Diagram 5] Figures 2 to 9 show cross-sectional views of a filter press with five support plates, each representing a different step in the solid-liquid separation process: Figure 5 shows the pre-compression step. [Figure 6] Figures 2-9 show cross-sectional views of a filter press with five support plates, each representing a different step in the solid-liquid separation process. Figure 6 shows the start of sparging. [Figure 7] Figures 2-9 show cross-sectional views of a filter press with five support plates, each representing a different step in the solid-liquid separation process: Figure 7 shows the sparging step; [Figure 8] Figures 2-9 show cross-sectional views of a filter press with five support plates, each representing a different step in the solid-liquid separation process. Figure 8 shows the final compression step. [Figure 9] Figures 2 to 9 show cross-sectional views of a filter press with five support plates, each representing a different step in the solid-liquid separation process. Figure 9 shows the discharge stage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Figure 1 shows two support plates 1 joined by a peripheral frame. Each support plate 1 has a filter cloth 2 on one side and a flexible elastomeric membrane 3 on the other side, thereby forming in series a compression chamber 4, a filtration chamber 5 and a collection chamber 6. The plates may have one or more central bosses (not shown).

[0050] The side of the plate facing the filter fabric may have a filtration drainage pad. The filtration chamber 5 is connected to a lower inlet or supply channel 7. The collection chamber is connected to a lower collection channel 8 and an upper collection channel 9. The compression chamber 4 is connected to a compressed fluid supply channel 10. EXAMPLES

[0051] This example details a method for producing oat milk using raw oats, which are oats from which part of the grain husk has been removed.

[0052] [Raw material pretreatment] Oat kernels have special properties with regard to composition and structure and require different processing than other cereals.

[0053] When producing oat milk, whole oat grains are typically stripped of their hulls, which are indigestible and undesirable for organoleptic reasons in the final product.

[0054] However, in the present invention, it is necessary to form a porous filter cake to ensure good filtration efficiency, and further, sparging of this filter cake can be performed to recover as much extract as possible.

[0055] Complete removal of the husk from the oat kernel would not leave enough insoluble compounds to form such a filter cake, and the inventors have realised that if the oat kernel husk is completely removed, clogging problems may arise in filtration.

[0056] In order to establish a compromise between the filterability of the filter suspension and the organoleptic quality of the product, the Applicant has treated oat kernels with a view to partially removing the hull.

[0057] Various techniques exist for separating some or all of the hulls before or after crushing the whole kernel, in this example the inventors have chosen to remove some of the hulls after crushing the oat kernels.

[0058] [Crush] The pilot mill used is a hammer mill with a 9.2 kW motor, which drives four rows of six hammers. A forced ventilation system ensures that any fine particles generated during the grinding process are conveyed outside and captured in a fabric filter sleeve to avoid any explosion risk inside the mill.

[0059] The sieve installed for grinding has holes with a diameter of 3 mm.

[0060] After milling, the entire mill is passed through a vibrating screen (Russell Finex EcoSeparator, 2 mm screen, 30 in.) to separate out some of the husks (hull removal). The coarsest fraction retained on the screen (mostly husks) is separated from the rest of the mill, accounting for 17% of the total grain mass.

[0061] [Suspension (Mashing / Watering)] The resulting grind (with the husks partially removed) is then sent by a screw to a hydrator where it is mixed with water. The mash water temperature is set at 55°C and the total amount of water is set to a final water ratio of 2.5 liters per kg of grind.

[0062] This water / grind ratio is reduced compared to the oat milk production according to the prior art and is inherent to the use of plate filter presses. In fact, the filtration cycle of the filter press advantageously includes a sparging step that allows the recovery of the extract contained in the filter cake. The final concentration of the juice after solid-liquid separation therefore includes the amount of water introduced in the suspension stage and in the sparging stage during the filtration cycle. The water addition ratio is defined on this basis.

[0063] The use of a more concentrated suspension also reduces the thermal energy consumption associated with the upstream steps of solid-liquid separation.

[0064] In this example, 42 kg of partially dehulled raw oats were ground and mixed with 105 L of water at 55° C., i.e. a water ratio of 2.5 liters per kg of ground oats.

[0065] The thermal energy required to heat and cool this suspension during hydrolysis is estimated to be about 30% lower than the thermal energy required to heat and cool a suspension with a water ratio of about 4-5 L per kg of oat mill.

[0066] After adjusting the pH to 6 with phosphoric acid and adding α-amylase to promote the conversion of starch to monosaccharides, the suspension obtained is subjected to the following hydrolysis diagram, optimized for the action of these enzymes: -75℃ 30 min Heat up to -85℃

[0067] This is a simple hydrolysis diagram and it is of course possible to consider other recipes involving other enzymes and other temperature levels depending on the desired composition of the final product (sugars, proteins, β-glucans, etc.).

[0068] Heating at each stage, with a rate of 1° C. / min and temperature maintenance, is ensured by injecting low pressure steam (Meura's "Aflosjet®" system) directly into the product.

[0069] This results in a suspension of hydrolyzed oats.

[0070] [Solid-liquid separation] The suspension is then filtered using a four-chamber "Meura 2001 Hybrid Micro" filter, which has a total nominal capacity of 44 kg malt equivalent (11 kg per chamber). The filtration cycle follows the following steps:

[0071] - Filling (Figure 3): The suspension is pumped to the filter through the feed channel 7 using a centrifugal pump operating at constant speed, filling the filtration chamber 5 in 2-4 min.

[0072] - Filtration (Figure 4): The remaining suspension is transferred to the filter, where a filtration effect is achieved by the gradual formation of a cake 11 of insoluble material of the suspension on the filter cloth 2. The suspension is first pumped at a constant flow rate (7.5 L / min) until a controlled pressure (450 mbar) is reached, and then this pressure is maintained in the filter. The entire suspension is transferred to the filter in 21 minutes, and 71 L of concentrated juice at 16.9 °Plato are collected through the collection channels 8 and 9. The Plato unit represents the mass percentage of the extract in the filtrate.

[0073] - Pre-compression (Fig. 5): Air (450 mbar) is injected through the feed channel 10 into the compression chamber 4 of each filter element for 5 minutes to pre-compress the pre-formed filter cake 11. This step recovers an additional 8 L of concentrated juice and homogenizes the porosity of the filter cake for efficient sparging.

[0074] - Sparging (Figures 6 and 7): Then, 65 L of water at 85°C is pumped in 61 minutes into the filtration chamber 5 and passed through the filter cake 11 in order to recover as much extract as possible from the filter cake 11. During this stage, the concentration of the juice at the filter outlet gradually decreases as the water flushes away the extract contained in the filter cake, reaching 1-2 degrees Platinum at the end of the sparging.

[0075] - Final pressing (Figure 8): Air is again pumped into the pressing chamber 4 (700 mbar) for 5 minutes to compress the filter cake 11, recovering maximum extract while drying the filter cake to facilitate the removal of the husks. A total of 148 L of oat juice was recovered in 1 hour 34 minutes at 14.0 degrees Plato.

[0076] - Discharge (Figure 9): At the end of the cycle, the filter is opened and the filter cake (okara) with a moisture content of 75% is discharged.

[0077] The main difference between this type of separation compared to decanter centrifugation without sparging or high pressure filter press separation is that the extractables present in the filter cake (okara) are recovered and become an integral part of the final product.

[0078] The filtration and pre-pressing stages make it possible to recover 79 L of juice at 16.9 degrees Plato, which corresponds to 65% of the total extract recovered during the filtration cycle. The final sparging and pressing stages make it possible to recover an additional 35% of extract.

[0079] [Post-treatment (formulation and homogenization)] To obtain the oat "milk", the juice collected at the outlet of the filter is cooled, then diluted with water to obtain the desired final concentration and transferred to a homogenization tank.

[0080] Sunflower oil (3.3 mL per liter of juice) and 20% sodium chloride solution (14 mL per kg of grounds) were added and the mixture was homogenized. The mixture was stirred for 10 minutes with a rotor / stator (Boccard "Mixturall") rotating at 3000 rpm, resulting in a stable emulsion. EXAMPLES

[0081] This second example details a method for producing oat milk from raw oats that have been pre-treated by partial dehulling followed by heat treatment with steam.

[0082] [Raw material pretreatment] The pretreatment of the raw materials aims to improve the organoleptic qualities of the final product and is carried out here in two separate and interchangeable steps: 1. In the solid-liquid separation stage, the husks are partially separated from the grain, taking care to retain a certain percentage of the husks necessary for the formation of a filter cake. 2. Heat treatment of grains

[0083] In the first stage, the oats are characterized by having a husk that can be easily separated from the endosperm, which is separated from the grain by an impact dehuller before being removed by an aerodynamic separation system. Starting from 60 kg of raw oats, this makes it possible to remove 12 kg of husks, i.e. 20% of the total grain mass.

[0084] Then, in a second stage, the remaining fraction, consisting mostly of naked kernels, is subjected to a heat treatment. Indeed, due to its high lipid content, oats are particularly susceptible to oxidation, which would spoil the final product if not previously heat-treated. In this example, a steam contact treatment of 20 minutes is applied.

[0085] [Crushing / Watering] In this second example, wet grinding was applied. The pilot mill used is a hammer mill equipped with an 18.5 kW motor. The motor drives 4 rows of 11 hammers. The sieve installed has holes with a diameter of 3 mm. A mixture of water and grain is made in the grinding chamber.

[0086] The grain feed rate is set at 2.4 kg / min and the water flow rate at 4.8 L / min to achieve an instantaneous mashing ratio of 2 L / kg. The grain, still hot from the steaming process, is ground and mashed simultaneously with mashing water at 25°C, reaching a final temperature of approximately 55°C. The mashing water contains the additives (KMS and calcium) and enzymes (10 kg α-amylase per 1 T of oats) required for mashing and hydrolysis.

[0087] At the end of the grinding process, a certain amount of rinse water is used to wash out residual particles from the grinding chamber. The volume of this water is set to give a total mashing ratio of 2.3 L / kg. Thus, 43.7 kg of pretreated oats were mixed with 100.6 L of water.

[0088] After milling, the resulting suspension is continuously pumped from the buffer tank to the hydrolysis tank.

[0089] [Hydrolysis] After adjusting the pH to 6 with phosphoric acid, the suspension, which also contains the enzymes that promote the conversion of starch into monosaccharides, is subjected to the following hydrolysis diagram, optimized for the action of these enzymes: -Initial temperature 55℃ -75℃ 30 min Heat up to -85℃

[0090] Heating, with a temperature ramp of 1° C. / min and a temperature rest at each stage, is ensured by injecting low pressure steam (Meura's "Aflosjet®" system) directly into the product.

[0091] This gives a suspension of hydrolyzed oats. Control tests with an iodine solution (0.02N solution in contact with the suspension) confirm (neutral coloration) or not (black / purple coloration) the conversion of starch.

[0092] [Solid-liquid separation] The suspension is then filtered using a four-chamber "Meura 2001 Hybrid Micro" filter, which has a nominal total capacity of 44 kg of malt equivalent (11 kg per chamber). The filtration cycle follows the following steps:

[0093] - Filling (Figure 3): The suspension is pumped to the filter through the feed channel 7 using a centrifugal pump, filling the filtration chamber 5 for 2-4 min.

[0094] - Filtration (Figure 4): The remaining suspension is transferred to the filter. The entire amount of suspension is transferred to the filter in 9 minutes. As the filter cake forms, the pressure gradually increases and reaches 0.4-0.5 bar. 70 L of concentrated juice at 18.8 °Plato are collected through collection channels 8 and 9.

[0095] - Pre-compression (Figure 5): An additional 33 L of concentrated juice is collected by injecting air (350 mbar) through the feed channel 10 into the compression chamber 4 of each filter element, homogenizing the porosity of the filter cake for efficient sparging. This step lasts for 5 minutes.

[0096] - Sparging (Figures 6 and 7): 38 L of water at 85°C is pumped into the filtration chamber 5 in 14 minutes, passing through the filter cake 11 in order to recover as much of the extract contained in the filter cake 11 as possible.

[0097] - Final pressing (Figure 8): air is again pumped into the pressing chamber 4 (700 mbar) for 8 minutes to compress the filter cake 11, recovering maximum extract while drying the filter cake to facilitate removal of the husks. A further 25 L of juice is recovered from the pressing.

[0098] A total of 168 L of "oat juice" was collected in 38 minutes at 14.6°C. The juice turbidity was measured at 748 FAU and the amount of sediment was 2 g / 100 g juice.

[0099] - Discharge (Figure 9): At the end of the cycle, the filter is opened and the filter cake (okara) with a moisture content of 58% is discharged.

[0100] [Post-processing (blending and homogenization)] To obtain the oat "milk", the juice collected at the outlet of the filter is cooled using a plate exchanger, then diluted with water to obtain the desired final concentration (13 degrees Platinum) and transferred to a homogenization tank.

[0101] Sunflower oil (10 mL per L juice) and 20% sodium chloride solution (3.7 mL per L juice) are added and the mixture is homogenized. The mixture is stirred for 10 minutes with a rotor / stator (Boccard "Mixturall") rotating at 3000 rpm, resulting in a stable emulsion.

[0102] [advantage] The advantages of using membrane bed filters are: - Produces clarified juice with optimized cycle times. - Sparging of the filter cake allows the recovery of a large portion of the extractables from the hydrolyzed suspension. - Producing okara with reduced moisture levels reduces the risk of contamination and transportation and storage costs.

[0103] The invention also makes it possible to optimize the efficiency of the separation cycle compared to the state of the art, in particular by means of a sparging step, which makes it possible to recover almost all of the residual extractives in the filter cake (spent grains or "okara").

[0104] The invention also makes it possible to reduce the electrical and thermal consumption of the process: if part of the water taken up in the product to reach the final concentration is added in the sparging stage, the operation upstream of the filter (hydrolysis) is carried out at a higher concentration (reduced ratio of water per kg of raw material), so that less suspension needs to be heated in the tank before filtration.

[0105] Another advantage is that filter presses do not require high powered electric motors, such as decanter centrifuges.

Claims

1. 1. A method for producing a dairy substitute, comprising: at least, - suspending a plant-derived material containing the compound to be extracted; - solid-liquid separation by means of a plate filter press comprising at least one successive filtration chamber (5) and a filter medium (2), - filling the filter with the suspension to be filtered; filtering the suspension and forming a porous filter cake (11) on the filter medium (2); and - a solid-liquid separation step, including a discharge step; - homogenizing the filtrate obtained from the solid-liquid separation step, said homogenization comprising high shear stirring to obtain a stable colloidal beverage; A method comprising:

2. 10. The method of claim 1, further comprising the step of pretreating the feedstock prior to the suspending step.

3. 3. The method of claim 2, wherein said pre-treatment comprises heat treating said feedstock.

4. 3. The method of claim 2, wherein the pre-treatment comprises grinding the plant-derived raw material.

5. 3. The method of claim 2, wherein the pretreatment comprises a step of dehulling the raw material, removing 2 to 30% by weight of the raw material.

6. 6. The method according to claim 5, characterized in that the mashing water is introduced in such a way that the weight ratio of water to plant-derived material is comprised between 0.5 and 6.

7. 2. The method according to claim 1, characterized in that the solid-liquid separation step is carried out at a pressure of less than 2 bar, preferably less than 1 bar, and even more preferably between 0.3 and 0.8 bar.

8. 2. The method of claim 1, wherein the step of solid-liquid separation comprises sparging the filter cake (11).

9. 2. The method according to claim 1, characterized in that the plate filter press comprises an elastomeric membrane (3), and at the end of the filtration, the elastomeric membrane (3) is inflated with a fluid to compress the filter cake (11).

10. 10. The method according to claim 9, characterized in that at the end of sparging, the elastomeric membrane (3) is expanded with the aid of a fluid to compress the filter cake (11).

11. 10. The method of claim 1, wherein the homogenizing step is carried out in a pressure homogenizer.

12. Use of a filter press comprising a series of filtration chambers (5) and a filter medium (2) for solid-liquid separation of a suspension of raw material of plant origin containing compounds to be extracted for the production of dairy substitutes, comprising: the plant-derived raw materials are selected from nuts including almonds, walnuts, hazelnuts, cashews, and macadamia nuts; grains including barley, wheat, spelt, rice, and oats; legumes including soybeans and peanuts; seeds including coconuts, sunflowers, and hemp; and tubers including potatoes and cassava; The solid-liquid separation - filling the filtration chamber (5), - filtering the suspension and forming a porous filter cake (11) on the filter medium (2); - sparging the filter cake (11); - discharging, Use of a filter press.

13. 13. Use according to claim 12, characterized in that the solid-liquid separation comprises at least one compression stage of the filter cake (11).

14. 14. Use according to claim 13, characterized in that a compression step is carried out before the sparging of the filter cake (11).

15. 14. Use according to claim 13, characterized in that a compression step is carried out after the sparging of the filter cake (11).

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