Plant-based milk substitute

Abstract

The present invention relates to a method of producing a plant-based milk substitute having a solids content in the range of 30-70%, based on the total weight of the plant-based milk substitute, comprising the steps of dry grinding of a plant-based starting material; production of an aqueous suspension of the dry-ground material in water with stirring at a temperature in the range from 20 to 60°C in the presence of an enzyme; and wet grinding of the suspension obtained at a temperature below 60°C and a pressure of less than 3 bar. The present invention further relates to a plant-based milk substitute having a solids content in the range of 30-70% which is obtainable by this method.

Description

[0001] Plant-based milk substitute

[0002] The present invention relates to a plant-based milk substitute and a method for its production.

[0003] Plant-based milk alternatives made from grains, nuts, or legumes, such as oat milk or other grain-based milk substitutes, are used as alternatives to conventional milk, for example, when following a lactose-free or vegan diet. Grain milk can be made from rice (rice milk), oats (oat milk), spelt, millet, rye, einkorn, or pseudocereals like buckwheat, and resembles cow's milk in appearance and consistency.

[0004] In the industrial production of grain milk, suitable grain flour (or alternatively grain kernels, grits or flakes), such as oat flour, is usually mixed with water and enzymes, hydrolyzed and separated from solid residues (see e.g. https: / / fruitprocessingmachine.com / portfolio-items / oat-milk-processing-line / ).

[0005] These solid residues, also known as okara, are removed as a side stream from the grain milk production process. This is detrimental both from the perspective of reducing the product yield from the starting material (up to 30% okara is separated as a side stream) and in terms of reducing the nutritional value of the product. Valuable nutrients such as beta-glucan, fiber, and protein are lost through the separation of okara.

[0006] Because okara has a high nutritional value, it is currently processed separately into other products such as animal feed. However, this is complex and economically and ecologically disadvantageous. Therefore, there is a need for an alternative process that does not generate any okara by-product.

[0007] WO 2021 / 144005 A1 describes the production of a milk substitute product in which a suspension made from a suitable plant-based starting material is subjected to high-pressure homogenization at a pressure of at least 800 bar. The product is subjected to very high temperatures and stresses during this process. Due to the high pressure, high shear forces, and heating, structural changes, including protein denaturation, can occur. This process is not industrially feasible if higher solids contents of more than 35% by weight are desired.

[0008] The object of the present invention was to provide a plant-based milk substitute and a method for its production in which no gentle processing is carried out at relatively low temperatures, pressures and lower shear forces, no by-stream of okara is produced and all important nutrients of the grain remain in the product.

[0009] The above problem is solved by the present invention.

[0010] In detail, the present invention relates to a process for producing a plant-based milk substitute with a solids content in the range of 30-70%, based on the total weight of the plant-based milk substitute, comprising the steps: a) optionally dry milling of a plant-based starting material; b) preparation of an aqueous suspension of the dry-milled material in water by stirring at a temperature in the range of 20 to 60 °C in the presence of an enzyme; c) wet milling of the suspension obtained in step b) at a temperature below 60 °C and a pressure of less than 3 bar.

[0011] According to the invention, it has been found that a plant-based milk substitute, optionally after dry milling, can be soaked in water, enzymatically treated, and subsequently wet-milled, thereby reducing the solids that would otherwise be present as okara to a size suitable for beverage consumption. The plant-based milk substitute produced in this way has a higher nutritional value than conventional plant-based milk substitutes and at the same time a pleasant and creamy mouthfeel.

[0012] Furthermore, the plant-based milk substitute according to the invention exhibits high storage stability and dilution properties.

[0013] The inventive process, by combining minimally processed raw materials with wet milling, achieves the most efficient solution in terms of energy and sustainability. Furthermore, it was found that the solids content in the milk substitute can be increased to a range of 30-70%, based on the total weight of the plant-based milk substitute, using the inventive process. It was found that such high solids contents cannot be achieved in milk substitutes using the method described in EP-2 838 375 Bl. Any edible cereal, pseudocereal, pulse, or nut material can be used as the plant-based starting material. Examples include rice, oats, spelt, millet, rye, einkorn, soybeans, broad beans, peanuts, hazelnuts, almonds, or pseudocereals such as buckwheat.According to the invention, oats are preferred as a plant-based starting material.

[0014] The plant-based starting material can be subjected to standard pretreatment steps such as cleaning, peeling, or kilning. These steps are well-known and do not require further explanation here.

[0015] In the first step of the inventive process, the optionally pretreated plant-based starting material, for example, oat groats, dried oat kernels, or whole-grain oat flakes, is subjected to dry milling, if necessary, to obtain whole grain flour, for example, oat flour. However, in certain embodiments of the present invention, it is also possible to start with kernels, groats, grits, and similar material and produce a suspension from them. Methods for producing a suspension from such starting materials are known to those skilled in the art, for example, by means of a colloid mill, an Ultraturax, ultrasonic treatment, or a homogenizer.

[0016] Dry milling processes and suitable mills are known.

[0017] According to the invention, dry grinding is preferably carried out with a hammer mill, preferably a fine grinding hammer mill (pulverizing hammer mill) with a granulation range of 0.1 to 2700 pm. Such hammer mills are known and available, for example, from the company Bühler.

[0018] Preferably, the plant-based starting material is ground to a particle size in the range of 0.1 to 600 pm, preferably in the range of 1 to 250 pm.

[0019] No sieving is required to obtain the whole oat kernel. The resulting dry-milled material can therefore be transferred to the next processing step without sieving.

[0020] At this stage of the process, common additives can be added to the material, which may be dry-milled. Examples include oat bran, beta-glucans, proteins, or vitamins.

[0021] In the next process step, an aqueous suspension of the optionally dry-milled material is prepared in water under stirring at a temperature in the range of 20 to 60 °C in the presence of an enzyme. In other words, the material is soaked.

[0022] The water used is adjusted to a desired temperature before being added, depending on the enzyme used in this step. According to the invention, the water is preferably brought to a temperature in the range of 20 to 60 °C, more preferably 25 to 50 °C.

[0023] A selected quantity of the optionally dry-milled material and the desired enzyme are then added. According to the invention, preferably such a quantity of the optionally dry-milled material is added to the water that the resulting suspension has a solids content in the range of 30-70%, preferably 40-60%, based on the total weight of the suspension.

[0024] According to another embodiment of the present invention, conventional additives can be added at this process stage. Examples include oat bran, β-glucans, proteins, or vitamins. These additives can preferably be added directly to the mixture described above.

[0025] The exact quantities of possibly dry-milled material, water, enzyme(s) and possibly additives depend on the type and desired properties of the product to be manufactured and can be routinely adjusted by a specialist.

[0026] The suspension can be produced in any container, vessel or reactor commonly used for this purpose, which has a temperature control unit such as a heater and preferably a stirrer.

[0027] The temperature of the mixture is then increased until the activation temperature of the selected enzyme is reached. In the case of α-amylase, the activation temperature is typically in the range of 70 to 75 °C. In the case of β-amylase, the activation temperature is typically in the range of 60 to 65 °C.

[0028] The hydrolysis of the optionally dry-milled material is carried out at the selected activation temperature of the chosen enzyme, with stirring, for a time sufficient for hydrolysis. This time depends on the conditions (temperature,

[0029] The duration of the hydrolysis step depends on the type and quantity of enzyme and the desired product properties (viscosity, sweetness), and is typically in the range of 1 minute to 2 hours, preferably 30 to 60 minutes. The temperature of the mixture is then changed (cooled or further heated), thereby inactivating the enzyme. If only a single such hydrolysis step is performed, cooling to ambient temperature, preferably 20°C, is preferred.

[0030] According to one embodiment of the present invention, the hydrolysis step can be carried out several times and preferably with different enzymes. In this case, after a prior hydrolysis step, the mixture is preferably not cooled to ambient temperature, but remains at a higher temperature, preferably in the range of 40 to 60 °C.

[0031] According to a preferred embodiment of the present invention, in step b)

[0032] - a mixture of optionally dry-milled material, water and α-amylase produced ,

[0033] - which is then treated by heating to the enzyme activation temperature, preferably in the range of 70 to 75 °C, and stirring,

[0034] - is then cooled, preferably to a temperature in the range of 40 to 60 °C, and β-amylase is added, and

[0035] - then treated by heating to the enzyme activation temperature, preferably in the range of 60 to 65 °C, and stirring, and subsequently the enzyme is inactivated, preferably by cooling the mixture.

[0036] According to a further embodiment of the present invention, the pH can be adjusted during step b) to support hydrolysis or to modify the activity of the enzyme(s) present. For example, the pH of the mixture can be adjusted to a range of 4 to 11, preferably 8 to 9, 5, by known means (such as the addition of suitable acids or bases).

[0037] If the suspension has a pH value in the acidic or alkaline range as a result, neutralization is preferably carried out in the further course of step b) , preferably at the end of step b) , by means of known measures (such as the addition of suitable acids or bases) so that the suspension has a pH value of 7 after step b) .

[0038] According to a further embodiment of the present invention, in step b) the material from step a) is comminuted. For example, this comminution can be carried out using a rotor-stator disperser, in particular a cutting mill. This is particularly suitable for embodiments in which the material is not subjected to dry grinding.

[0039] After hydrolysis and cooling, the suspension obtained in step b) is subjected to wet milling. Wet milling reduces the size of the solid components of the suspension to such a degree that they are no longer perceptible to the senses. According to the invention, this process allows valuable components to remain in the final product, which would otherwise be separated as O-kara in a side stream. The milk substitute obtained according to the invention is therefore more nutritious and offers economic and ecological advantages in its production.

[0040] According to the invention, wet grinding is carried out gently at a temperature below 70°C, preferably in the range of 5 to 65°C, more preferably 15 to 60°C, and at a pressure of less than 3 bar, preferably 1 to 3 bar and more preferably 1.5 to 2 bar. It has been shown that wet grinding carried out under these gentle conditions is sufficient for the purposes of the invention. In this way, the material is not subjected to excessive stress and retains its advantageous properties.

[0041] According to the invention, the wet grinding in step c) is preferably carried out using a stirred ball mill.

[0042] According to the invention, in wet grinding in step c), a specific energy in the range of 30 to 1000 kWh / t, preferably in the range of 40 to 500 kWh / t and particularly preferably in the range of 50 to 400 kWh / t, is introduced into the aqueous suspension obtained in step b).

[0043] According to the invention, conventional stirred ball mills can be used. The mill design can be horizontal or vertical. It can be, for example, a disc mill, a pin mill, or a pin-counterpin mill. The grinding media separation can be designed, for example, as a screen or slot separator. The rotor and / or the stator of the agitator can be made of metal, ceramic, or plastic / polymer (for example, polyurethane or polyamide).

[0044] According to the invention, grinding media (spheres) can preferably be made of ceramic, e.g. zirconium oxide stabilized with cerium or yttrium.

[0045] According to the invention, the size of the grinding media is preferably in

[0046] The grinding media ranges from 0.03 to 50 mm, preferably 0.1 to 10 mm, and particularly preferably 0.5 to 5 mm. In the case of multi-stage grinding, different grinding media (type, size) can be used in different grinding steps. Properties such as viscosity, granulation, appearance of the final product, and sensory properties of the final product can be adjusted as desired by varying the size of the grinding media.

[0047] According to the invention, wet grinding can be carried out as a single or multiple pass, i.e. the material is subjected to one or, if applicable, several, preferably 1 to 4, more preferably 1 to 2 wet grinding steps.

[0048] Multiple passes can be achieved by passing the material through a mill multiple times (recirculation), or alternatively, by passing it through several mills arranged in succession. In the first case, the outlet of one mill is preferably connected to its inlet to achieve recirculation of the material through that mill. In the second case, the outlet of each preceding mill is preferably connected to the inlet of the subsequent mill. However, it is also conceivable to take the material from an outlet and, for example, manually introduce it into the inlet of the same or a downstream mill.

[0049] According to the invention, wet grinding is preferably carried out by introducing a specific energy in the range of 30 to 1000 kWh / t, preferably in the range of 40 to 500 kWh / t, and particularly preferably in the range of 50 to 400 kWh / t, into the aqueous suspension obtained in step b). In the case of multiple passes, this specific energy is introduced for each pass. The introduced specific energy depends on the type of product to be ground (size, hardness, etc.) as well as the applied process conditions (such as the size of the grinding media).

[0050] According to the invention, the specific energy is related to the suspension to be treated.

[0051] For a single passage, the specific energy is defined as follows:

[0052] Net power input [kW]

[0053] E [kWh / t] =

[0054] Mass flow [t / h]

[0055] When driving in multiple passes, the specific [result] arises.

[0056] Energy from the sum of the specific energy of all passages.

[0057] In a recirculation mode (multiple passages through a

[0058] In the mill, the specific energy is defined as follows:

[0059] Net power input [kW] E [kWh / t] = - — : - — — — - —

[0060] Batch size [t] ■ Processing time [h]

[0061] The flow rate of the material through the wet milling process depends on the type of wet mill (n).

[0062] According to the invention, wet grinding is preferably carried out at a rotational speed of 6 to 15 m / s, preferably 7 to 18 m / s, more preferably 8 to 12 m / s.

[0063] According to the invention, wet grinding can be carried out with or without cooling.

[0064] The inventive process is energy-optimized by the use of dry and wet grinding. The inventive process can be carried out batchwise or continuously. In a continuous process, the individual components of the system, in which steps a) to c) are carried out, are connected to each other, for example, by pipes, so that the material can be conveyed through the system without interruption. The flow through the system can be regulated in a known manner, for example, by means of pumps and / or shut-off devices such as valves or gates.

[0065] The present invention therefore also relates to a plant for carrying out the inventive method for producing a plant-based milk substitute, comprising

[0066] - a dry grinding unit, preferably a hammer mill, particularly preferably a fine grinding hammer mill with a granulation range of 0.1 to 2700 pm;

[0067] - a unit for producing an aqueous suspension from a dry-milled material; and

[0068] - a wet milling unit, preferably a stirred ball mill .

[0069] The units have already been described above in relation to the procedure.

[0070] Preferably, the system is designed for continuous operation, for example by connecting the various units to each other via conduit pipes, so that the material can be conveyed through the system without interruption.

[0071] The flow rate through the system can be regulated in known ways, for example by means of pumps and / or shut-off devices such as valves or locks. The exact design of the system can be individually adapted to the user's specific requirements. This includes, among other things, the type and dimensions of the individual units, the provision of units for temperature and pressure regulation in the individual units, as well as the type and number of crushing and grinding media used (screen sizes in the hammer mills, balls in the ball mills).

[0072] The product obtained by the inventive process has a solids content in the range of 30-70%, preferably 40-60%, based on the total weight of the plant-based milk substitute. It contains the solids, preferably okara, which are separated and otherwise utilized in conventional products, and thus has a higher nutritional value than conventional milk substitutes.

[0073] The product obtained by the inventive process can be adjusted with regard to its external and sensory properties (for example, color, texture, mouthfeel) as described above by varying the process conditions (for example, energy input during wet milling) accordingly.

[0074] The product obtained by the inventive method can, for example, be aseptically packaged to extend its shelf life. Preferably, the material can be subjected to conventional processing steps such as heat treatment (to kill germs) and homogenization before aseptic packaging.

[0075] If the inventive process is carried out with oats as the plant material, the product obtained by the inventive process is the so-called oat base. The product obtained by the inventive process can also be further processed into a desired milk substitute by, for example, mixing commonly used additives such as emulsifiers, flavorings, and stabilizers with the product obtained from the inventive process and then carrying out conventional processing steps such as heat treatment (to kill germs) and homogenization. If the inventive process is carried out with oats as the plant material, the product processed in this way can be an oat beverage.

[0076] The present invention is explained in more detail with reference to non-limiting examples and figures. These show:

[0077] Fig. 1 shows a flowchart of an embodiment of the inventive process for producing a milk substitute from wholemeal flour;

[0078] Fig. 2 shows a flowchart of an embodiment of the inventive process for producing a milk substitute from whole grain cereals;

[0079] Fig. 3 shows a flowchart of an embodiment of the inventive process for producing a milk substitute from pulses or cereals with low starch content or nuts with shells without enzymatic treatment.

[0080] In the figures, identical reference symbols have the same meaning.

[0081] Figure 1 shows a flowchart of an embodiment of the inventive process for producing a milk substitute from whole grain flour. In step 100, the whole grain flour used is dry-milled as described above.

[0082] In step 200, the dry-milled whole grain flour from step 100 and water are combined in a suitable container, preferably a reactor. In step 210, the dry-milled whole grain flour and water are mixed together while stirring. In step 220, the mixture is adjusted to a desired pH by adding an acid or base. In step 230, a desired enzyme, such as α-amylase, is added. In step 240, the suspension is heated to the enzyme activation temperature (approximately 70–75 °C in the case of α-amylase). In step 250, the enzyme is inactivated by heating or cooling the suspension to a temperature outside the enzyme activation temperature. In step 260, the pH of the suspension is adjusted to neutral (7) by adding an acid or base.

[0083] In step 300, the suspension thus prepared is transferred to a stirred mill and wet-milled as described above. After wet-milling, the product is preferably cooled in step 400 and can then be aseptically packaged or further processed as described above.

[0084] Similarly, a product can also be made from flour made from legumes or nuts with shells.

[0085] Figure 2 shows a flowchart of an embodiment of the inventive process for producing a milk substitute from whole grain cereals. The whole grain cereals can be in the form of kernels, grits, meal, or flakes. The process flow corresponds to that shown in Figure 1. However, in step b) of the inventive process, steps 231 of soaking the material (allowing it to stand for a longer period) and 232 of comminution of the material (as described above) are carried out before the suspension is heated to the enzyme activation temperature in step 240.

[0086] Furthermore, if necessary, step 270 of further comminution of the material (as described above) can be carried out before the material is fed to step 300 of wet grinding.

[0087] Figure 3 shows a flowchart of an embodiment of the inventive process for producing a milk substitute from legumes or nuts with shells without enzymatic treatment. This process differs from the process shown in Figure 1 in that steps 220 to 260 can generally be omitted. Step 260 can be carried out optionally if necessary.

Claims

Patent claims 1. A process for producing a plant-based milk substitute with a solids content in the range of 30-70%, based on the total weight of the plant-based milk substitute, comprising the steps: a) Optionally, dry milling of a plant-based starting material; b) Preparation of an aqueous suspension of the dry-milled material in water by stirring at a temperature in the range of 20 to 60°C in the presence of an enzyme; c) Wet milling of the suspension obtained in step b) at a temperature below 60°C and a pressure of less than 3 bar.

2. The method according to claim 1, characterized in that the plant-based starting material is selected from the group consisting of cereal, pseudo-cereal, pulse and nut materials.

3. Method according to one of the preceding claims, characterized in that the dry grinding is carried out with a hammer mill, preferably a fine grinding hammer mill with a granulation range of 0.1 to 2700 pm.

4. Method according to one of the preceding claims, characterized in that the plant-based starting material is ground in step a) to a particle size in the range of 0.1 to 600 pm, preferably in the range of 1 to 250 pm.

5. Method according to one of the preceding claims, characterized in that the optionally dry-milled material from step a) is transferred unsieved to step b).

6. Method according to one of the preceding claims, characterized in that the enzyme in step b) is an amylase, preferably selected from the group consisting of α-amylase and β-amylase.

7. Method according to claim 6, characterized in that in step b) - a mixture of optionally dry-milled material, water and α-amylase produced, - is then treated by heating to the enzyme activation temperature, preferably in the range of 70 to 75 °C, and stirring, - then cooled, preferably to a temperature in the range of 40 to 60°C, and β-amylase is added, and - then treated by heating to the enzyme activation temperature, preferably in the range of 60 to 65 °C, and stirring, and subsequently the enzyme is inactivated, preferably by cooling the mixture.

8. Method according to one of the preceding claims, characterized in that the wet grinding in step c) is carried out with a stirred ball mill.

9. Method according to one of the preceding claims, characterized in that the wet grinding in step c) has a specific energy in the range of 30 to 1000 kWh / t, be- preferably in the range of 40 to 500 kWh / t and particularly preferably in the range of 50 to 400 kWh / t, into which the aqueous suspension obtained in step b) is introduced.

10. Method according to one of the preceding claims, characterized in that additives are added after step a), before or during step b).

11. Method according to one of the preceding claims, characterized in that in step b) a substance is added to adjust the pH value.

12. Method according to claim 11, characterized in that step b) is carried out in such a way that the aqueous suspension produced after step b) is adjusted to a neutral pH value.

13. Method according to one of the preceding claims, characterized in that in step b) a comminution of the optionally dry-ground material is carried out .

14. Plant-based milk substitute with a solids content in the range of 30-70%, obtainable by the method according to any one of claims 1 to 13.

15. Plant-based milk substitute according to claim 14, characterized in that it is an oat-based milk substitute.

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