Method and system for dispensing a product

Abstract

The present invention relates to a method for dispensing foamed food products, such as creams or aerated desserts, using a microfiltration device with a predetermined microfiltration wall. The present invention further relates to a foamed food product dispensing system configured to perform such a method, and to the use of a predetermined microfiltration wall in a foamed food product dispensing system configured to perform such a method.

Description

[Technical Field]

[0001] The present invention relates to a method for dispensing foamed food products, such as creams or aerated desserts, using a microfiltration device. The present invention further relates to a foamed food product dispensing system configured to perform such a method, and to the use of a microfiltration wall in a foamed food product dispensing system configured to perform such a method. [Background technology]

[0002] Foamed food product dispensing systems and methods for dispensing foamed food products using such dispensing systems are known in the art.

[0003] For example, WO 2022 / 066019 discloses a foamed product dispensing system, the system including a product dispensing machine configured to receive an exchangeable product container and a product container configured to cooperate with the product dispensing machine after being placed in the machine, the product container containing a foamable product, preferably a food product, such as cream, the product container is provided with a product processing unit including a whipping device having a product inlet for receiving the product and a product outlet for discharging the product, the processing unit is connectable to a gas supply for supplying gas to the product, and the system is configured to dispense the foamed product with a predetermined overrun of greater than 200%.

[0004] EP 2268173 discloses a method for dispensing a foamed product (P), such as a food product, characterized in that the product is fed to a microfiltration device, a gas is fed to the product (P) through the microfiltration device, and the product (P) downstream of the microfiltration device is subjected to a mixing treatment and / or a controlled decompression.

[0005] US Patent Application Publication No. 2020 / 360946 relates to a portable apparatus for dispensing and foaming a product, the portable apparatus including: a product container containing a product to be foamed by and dispensed from the apparatus; a gas container containing at least a gas, wherein the gas is substantially free of any greenhouse gases such as NO; a dispersion device having a product inlet connectable to the product container to receive the product, the dispersion device further connectable to the gas container to supply gas to the product during product discharge; a processing device downstream of the dispersion device for performing a mixing process and / or decompression on the product provided with the gas; and a product dispensing head that is part of a top section of the apparatus and is positioned downstream of the processing device.

[0006] Japanese Patent Application Laid-Open No. 2018-051483 provides a methane fermentation treatment device equipped with a hollow fiber membrane module.

[0007] Furthermore, WO 2011 / 028117 discloses a system and method for obtaining a specific, stable foamed product in a particularly efficient manner using relatively inexpensive, durable, and relatively low-energy means, thereby achieving particularly consistent product quality. More specifically, it discloses a method for dispensing a foamed product, characterized in that a gas is supplied to the product via a microfiltration device to introduce gas bubbles into the product to form a foamed and / or aerated product. Here, the product is supplied to the microfiltration device to be provided with gas. Thus, the microfiltration device can induce gas bubble formation in the product. The microfiltration device is described as having, among other things, a rigid wall separating a product feed-through space from a gas supply space. The filtering wall, also referred to as a membrane, is preferably provided with multiple flow-through channels (e.g., extending straight through the wall from the gas supply space to the product feed-through space), each of which has at least a relatively narrow outlet (each of which can also be a narrow channel). However, it has been found that foaming performance deteriorates over time, which is clearly undesirable. Furthermore, it has been found that the adsorption of proteins and / or fats onto the surface of the membrane and / or inside the pores of the membrane reduces the operational lifetime of the membrane. Summary of the Invention [Problem to be solved by the invention]

[0008] Accordingly, the object underlying the present invention is to provide an improved foamed food product dispensing system comprising a microfiltration device and a method for dispensing foamed food products using such a dispensing system, in which more consistent foaming performance is obtained and / or the operational life of the microfiltration device is extended. [Means for solving the problem]

[0009] It has been found that the above-mentioned objectives can be achieved by using a predetermined microfiltration wall in a foamed food product dispensing system comprising a microfiltration device, whereby a specific and consistent product quality for the foamed food product is achieved and / or the operational life of said microfiltration device is extended by using a predetermined microfiltration wall according to the invention.

[0010] Thus, in a first aspect, the present invention provides a method for dispensing a foamed food product, comprising: - the food product is fed to a microfiltration device provided with a microfiltration wall having gas-permeable holes separating a first space from a second space; - the food product is passed through the first space and flows along the micro-filtration wall, and the gas is supplied to the second space, or vice versa, so that the gas can be injected into the food product through the micro-filtration wall; - Food products undergo overruns ranging from 120 to 450% - the surface of the microfiltration wall on the side where the food product flows is hydrophobic, said surface having a contact angle with water of 110° or more; - The microfiltration wall has a porosity of 60% to 90% The present invention relates to a method characterized in that

[0011] In a further aspect, the present invention relates to a foamed food product dispensing system configured to carry out the method of the present invention.

[0012] In a further aspect, the present invention relates to the use of a predetermined microfiltration wall of the present invention in a foamed food product dispensing system comprising a microfiltration device and configured to carry out the method of the present invention, to extend the operating life of the microfiltration device and / or reduce variability in foaming performance.

[0013] In a first aspect, the present invention provides a method for dispensing a foamed food product, comprising: - the food product is fed to a microfiltration device provided with a microfiltration wall having gas-permeable pores separating a first space from a second space; - the food product is passed through the first space and flows along the micro-filtration wall, and the gas is supplied to the second space, or vice versa, so that the gas can be injected into the food product through the micro-filtration wall; - Food products undergo overruns ranging from 120 to 450% - the surface of the microfiltration wall on the side where the food product flows is hydrophobic, said surface having a contact angle with water of 110° or more; - The microfiltration wall has a porosity of 60% to 90% The present invention relates to a method characterized in that

[0014] When a substrate has a contact angle of less than 90°, this means that water tends to wet the surface of the substrate (i.e., it is hydrophilic), while when the contact angle is greater than 90°, it means that water does not tend to wet the surface of the substrate (i.e., it is hydrophobic). The surface of a microfiltration wall according to the present invention is superhydrophobic, which means that the surface has a contact angle with water of 110° or more. The microfiltration wall according to the present invention preferably has a contact angle with water of at least 118°, more preferably at least 120° or more, and most preferably at least 130° or more.

[0015] The water contact angle of a substrate is defined as the water contact angle measured after immersion in water at 20°C for 3 days. Suitable methods for measuring the water contact angle of a surface will be apparent to those skilled in the art. A suitable method is to perform water contact angle measurements using a 3 μl droplet of double-distilled water and diiodomethane with a contact angle DATAPHYSICS OCA-2 goniometer managed by OCA-2 software.

[0016] The porosity of the microfiltration walls used in accordance with the present invention is between 60% and 90%. The porosity of the membrane is calculated using the average mass of the polymer material and the mass of the liquid within the membrane. The densities of the membrane polymer and liquid are derived from literature or, if unknown in the literature, can be determined using techniques known in the art. The mass of the liquid-filled membrane is measured using the gravimetric "pat and weight" method. In the pat and weight method, the membrane is immersed in a wetting fluid (in this case, isopropyl alcohol) for 24 hours, tapped off the surface, and weighed immediately after removing the fluid by gently blowing the liquid out of the internal channels of the hollow fibers with compressed air. This process is repeated (three times), and the weights of the wet and dry membranes are measured. By comparing the masses of the wet and dry membranes, the membrane porosity can be calculated using the following formula: Porosity=[1-{(m f / ρ f ) / (m m / ρ m +m f / ρ f )}]×100% where m m = mass of the membrane, g m f = mass of fluid in the film, g ρ m = film density, g / cm 3 ρ f = density of the fluid, g / cm 3

[0017] It is important that the porosity of the microfiltration wall according to the present invention is 60% to 90%, preferably 70% to 90%, and most preferably 75% to 90%. If the porosity of the microfiltration wall is too low, the pressure rise in the microfiltration wall will be too high, which is undesirable. If the porosity of the membrane exceeds 90%, the mechanical strength of the membrane will be insufficient for practical use.

[0018] Preferably, the microfiltration walls used in accordance with the present invention have gas-permeable pores with an average pore size K in the range of 0.1 to 5 microns, particularly at least 0.2 microns (especially greater than 0.3 microns) and less than 3 microns. Most preferably, the microfiltration walls have an asymmetric structure and an average pore size range of 0.1 to 5 microns, most preferably 0.1 to 2 microns. In the case of asymmetric membranes, the more open side of the membrane is preferably the side through which the food product flows. Such a configuration has a beneficial effect on the operating pressure, which has been found to be particularly advantageous for more viscous products that need to be dispensed.

[0019] Pore ​​size and pore size distribution are measured by gas-liquid porometry, also known as capillary flow porometry (CFP). This technique, commonly known in the art, is based on the displacement of an inert and non-toxic wetting liquid embedded in a porous network by applying an inert pressurized gas. Therefore, only through-pores are measured. For asymmetric membranes, CFP is suitable for measuring the pore size and pore size distribution of the support layer, but this technique is inadequate for measuring large skin pores. The size of the skin pores is determined by SEM.

[0020] In more detail, CFP is based on the following (see https: / / wiki.anton-paar.com / sg-en / basics-of-capillary-flow-porometry): The sample under evaluation is wetted with a liquid, filling at least all through-pores. An increasing gas (nitrogen) pressure (P) is applied to one side of the sample. The liquid is expelled from each through-pore according to its size (pore diameter d) at a defined pressure according to the following equation: p=(4γ cosθ) / d where γ is the surface tension of the liquid and θ is the contact angle between the liquid and the sample. The resulting flow rate of gas through the empty pores is measured to calculate the maximum pore size from the bubble point (point B, FIG. 15, which shows the flow rate versus pressure data for the measured "wet" and "dry" runs, and also shows the calculated "semi-dry data" (dotted line) and the pressure "F" used to calculate the bubble point pressure "B" and the mean flow pore size).

[0021] A second data set of flow rate versus pressure through the completely dry sample is used in combination with the wet flow rate data to calculate the mean flow pore size (F, FIG. 16) and pore size distribution of all through-pores within the measurement system. (FIG. 16 shows the pore size distribution, i.e., pore diameter as a function of flow rate.) The maximum pore size (the upper limit of the pore size distribution) is determined by the flow rate at which the wet flow rate data linearizes (i.e., essentially equals the dry flow rate). The pore size distribution is usually expressed as a cumulative flow rate (percentage of total amount or volume per unit time) or differential flow rate, which is the first derivative of the cumulative curve, as shown in FIG. 16.

[0022] CFP measurements are performed assuming the pores have a spherical shape, using a Porolux 500 instrument, a N flow rate of 100 ml / min, and Quantachrome's Porofil™ wetting fluid (see https: / / www.quantachrome.com / porometer / porofil.html) as the wetting fluid (with a fluid tension of 16 dynes / cm and a contact angle = 0).

[0023] The expression "microfiltration wall with asymmetric structure" has its conventional meaning in the art, i.e., it refers to any membrane with an anisotropic structure throughout its cross-section (as opposed to a microfiltration wall with a symmetric structure, which means the membrane has a uniform cross-section). Typically, an asymmetric membrane consists of multiple layers, each with a different structure and permeability. A typical anisotropic membrane has a relatively dense upper layer supported on a more open, porous lower layer. According to the present invention, the more open side of the membrane is preferably the side through which the food product flows. The microfiltration wall itself can be manufactured from a variety of materials, as long as its surface has the required static water contact angle. In a preferred embodiment, a microfiltration wall coated with a hydrophobic layer is used. Due to this hydrophobic layer, the surface of the microfiltration wall has the required water contact angle of 110° or more (measured as described in detail above). The hydrophobic layer is preferably applied to a support material, preferably selected from the group consisting of glass, metal, rubber, polymer, and ceramic. The hydrophobic layer preferably has an average thickness of 20 to 300 nm, more preferably 20 to 100 nm, and most preferably 20 to 50 nm. The average thickness of the microfiltration wall as a whole, i.e., the average thickness of the wall including the hydrophobic layer, is preferably 450 to 900 μm, more preferably 450 to 750 μm, and most preferably 450 to 550 μm, as measured using a scanning electron microscope (SEM). The hydrophobic layer preferably comprises or consists of a material having a fluorocarbon skeleton, such as hepta-deca-fluorodecyl-acrylate or hexa-fluoro-propylene.

[0024] Preferably, the microfiltration walls according to the present invention are hollow fiber membranes coated with a hydrophobic layer as specified above.

[0025] The hydrophobic layer can be applied to the microfiltration wall via any of the methods available in the art, as described, for example, in N.F. Himma et al. "Advances in polypropylene membrane preparation and applications", in J. Polym. Eng. 2016, 36(4), especially pp. 341-344. Preferably, it is applied via one or more of the techniques selected from the group consisting of plasma coating, vapor deposition, chemical vapor deposition and dip coating.

[0026] In the method according to the present invention, a food product to be foamed is fed into a microfiltration device provided with a microfiltration wall having gas-permeable holes. The microfiltration wall separates a first space from a second space. The food product is passed through the first space and flows along the microfiltration wall. Gas is fed into the second space, and the gas can be injected into the food product through the microfiltration wall (particularly through the permeable holes contained in the wall). The food product undergoes an overrun in the range of 120-450% as a result of the gas being injected therein. As will be understood by those skilled in the art, this method can also be carried out in reverse, meaning that the space through which the food product is passed can be the second space, and the space to which the gas is supplied can be the first space. The respective spaces can also be referred to as the product feed-through space (the space through which the product passes) and the gas supply space. The supply of product to the product feed-through space can be carried out by a suitable fluid supply means, and the supply of gas to the second space can be carried out by a suitable gas supply means, as will be apparent to those skilled in the art.

[0027] Thus, the method provided by the present invention provides a foamed food product in a very rapid and reliable manner and in a hygienic manner. The method can be utilized on a small scale or, conversely, on a large scale. The foamed food product formed by the present invention can further provide a particularly pleasant taste when the product is intended to be consumed.

[0028] As will be appreciated by those skilled in the art, microfiltration devices can be designed in a variety of ways. Typically, the microfiltration wall separating the first space from the second space is sufficiently rigid. More specifically, the microfiltration wall is so rigid that it undergoes little or even no deformation under the influence of any pressure difference that may prevail between the first space and the second space during use, for example, a pressure difference of more than 1 bar or a smaller pressure difference (pressures referred to in this application are absolute pressures). The microfiltration device may comprise a single microfiltration wall or may comprise two or more parallel microfiltration walls.

[0029] The microfiltration wall of the present invention can be, for example, cylindrical, with a circular cross section. According to further refinements, the length of the wall (particularly the space through which the food product is passed and flows along the microfiltration wall, also referred to as the product feed-through channel, as described above) is at most 10 cm (i.e., 100 mm), in particular at most 5 cm (50 mm), more particularly at most 2 cm (20 mm), and at least 0.4 cm (4 mm), more particularly at least 0.5 cm (5 mm). The mentioned lengths are, for example, in the range of about 5 to 50 mm. In a relatively compact design, this length L is less than 35 mm, for example, about 5, 10, 20, 30, or 35 mm. Lengths of 18 to 33 mm are particularly preferred.

[0030] The gas used according to the present invention can comprise one or more gases, preferably selected from the group consisting of nitrogen, nitrogen oxides, carbon dioxide and air. Most preferably, the gas is air. The temperature of the gas (or gas mixture) to be supplied to the filtration device can be, for example, ambient temperature, for example, room temperature. The gas temperature can be, for example, in the range of 0 to 50°C, or another temperature, for example, a temperature higher than 50°C, or conversely, a temperature at or below 0°C.

[0031] The volume increase of a food product after foaming is typically expressed in terms of "overrun percentage" or simply "overrun." Overrun indicates the increase in volume of a product P after foaming relative to the volume of the unfoamed product and can be expressed as: Overrun = ((W p -W s ) / W s )×100% In the formula, W p represents the mass of the unfoamed product at a fixed volume, and W s represents the mass of the same volume of foamed product. Thus, an overrun percentage of 100% means that the volume of 100 ml after dispensing has increased to 200 ml.

[0032] The method according to the invention can be used to obtain a desired degree of aeration (overrun) for food products while maintaining high consistency of quality. Particularly high overruns can be obtained for various foamy food products. The overrun is typically at least 120%. For cream products, an overrun of 135 to 450%, more preferably 150 to 400%, is particularly preferred.

[0033] The food product to be foamed and dispensed according to the present invention may be, for example, a cream, a spray cream, a (fruit) juice / drink, an alcoholic beverage or beverage base, such as beer or wine, a dairy product or dairy-based beverage, such as a whey beverage or permeate-based beverage, a plant-based beverage (e.g., an oat-, soy-, coconut- or almond-based beverage), a (milk) shake, a chocolate beverage, a (drinkable) yogurt, a sauce, an ice cream or a dessert. Preferably, the present invention does not utilize a prefoam upstream of the filtration device, and at least an essentially not yet foamed product (i.e., a product in a substantially non-foamed state) is fed to the microfiltration device.

[0034] The food products downstream of the microfiltration device are - Mixing process, and / or - Controlled decompression It may take some time.

[0035] More specifically, in some embodiments, it is advantageous if the product undergoes a limited pressure drop downstream of the microfiltration device. This is particularly advantageous for liquids with a higher viscosity than milk, such as cream, whereby an operating pressure of at least 4 bar is preferably applied. Here, the product pressure can be gradually increased from a first pressure value to a second pressure value, the first pressure value being higher than the second pressure value (the pressure difference between the first and second pressures can be at least 1 bar or less). The first pressure can be, for example, superatmospheric pressure. The second pressure can be, for example, substantially atmospheric pressure. The pressure drop can be achieved, for example, by a product processing device suitable for this purpose (i.e., a pressure reducer, a pressure reduction device). The processing device can be configured, for example, to apply shear to the flowing product in order to reduce the pressure. A gradual pressure drop is applied, which applies shear to the product in a controlled manner, thereby sufficiently preventing or limiting product separation.

[0036] It appears that good results are obtained if the product undergoes a mixing process downstream of the microfiltration device, in order to obtain a particularly homogeneous foamed product. Here, it is particularly advantageous if the mixing process is carried out by a static mixing device. The mixing device can be, for example, a product processing device, and appears to be able to provide a pressure drop and shear to the product in a simple manner.

[0037] In some cases, it may be advantageous to gas the product through the microfiltration device without utilizing downstream mixing and / or controlled reduced pressure (relative to the microfiltration device). In such embodiments, the food product may undergo a mixing process upstream of the microfiltration device.

[0038] According to a further refinement of the invention, the gas can be introduced into the product via a microfiltration device under the influence of a pressure of more than 1.2 bar (absolute), for example in the range of more than 5 bar, in particular higher than 7 bar, for example in the range of 8 to 15 bar.

[0039] The method can include, for example, using a product flow rate and a gas flow rate where the ratio of product flow rate to gas flow rate is between 10:1 and 1:10. The gas flow rate can be, for example, greater than 10 liters per hour, for example, in the range of about 30 to 600 liters / hour (e.g., 50 to 300 liters / hour, more particularly 100 to 300 liters / hour), or can have a different value. The gas flow rate can be, for example, at least 7.7 L / hour and at most 20.3 L / hour.

[0040] In a further aspect, the present invention relates to a foamed food product dispensing system configured to carry out the method of the present invention, comprising a holder for accommodating the food product to be dispensed and a product discharge means for discharging the food product coming from the holder, the product discharge means being provided with a microfiltration device having a product inlet for supplying the product, the microfiltration device being connectable to a fluid supply for supplying gas to the product during product discharge, the product discharge means preferably further comprising a processing device, the processing device being arranged downstream of the microfiltration device for carrying out a mixing process and / or a decompression process on the food product to which gas is provided, the microfiltration device being provided with a microfiltration wall having gas-permeable holes separating the gas supply space associated with the fluid supply from the product feed-through channel associated with the product inlet, characterized in that the surface of the microfiltration wall on the side of the product feed-through channel is hydrophobic, the surface having a contact angle with water of 110° or more, and the microfiltration wall having a porosity of 60% to 90%.

[0041] In this way, the advantages mentioned above can be obtained.

[0042] As will be appreciated by those skilled in the art, the preferred embodiments detailed above for the method according to the present invention apply mutatis mutandis to the foamed food product dispensing system of the present invention.

[0043] The foamed food dispensing system may also comprise a product processing device, such as a mixing device, in particular a static mixer, which is arranged downstream of the microfiltration device. The product processing device may perform a mixing process to mix the foamed food product and / or may subject the foamed food product to a controlled pressure drop, in particular to produce a uniformly foamed food product.

[0044] The foamed food product dispensing system according to the present invention is simple to use, relatively fast, relatively reliable and robust (preferably has no moving parts), and easily cleanable and sanitary while maintaining quality. Furthermore, the system is fully scalable, i.e., the system can be designed to be relatively small (e.g., having a microfiltration device with a maximum dimension, e.g., length, of less than 35 mm) or, conversely, relatively large (e.g., having a microfiltration device with a maximum dimension, e.g., length, of 10-20 cm).

[0045] The mentioned product processing devices (e.g., static mixing devices) can be designed in various ways. According to further elaboration, the product processing device is designed to agitate (gas bubbles are provided) and / or change the course of the product flowing through the device (i.e., accelerate the product, preferably while the direction of the product velocity vector changes many times). The product processing device is not provided with any particularly moving parts and can passively mix the product.

[0046] The referenced product processing devices (e.g., static mixing devices) can be designed to, for example, maintain a substantially static obstacle (e.g., a substantially round obstacle, ball, marble, wall that affects flow rate, etc.) within the flow path of the product to process the product (e.g., pass the product through one or more non-linear paths through the product processing device).

[0047] The aerated product can be propelled through / along a product processing device, for example, under the influence of a suitable fluid pressure (particularly superatmospheric pressure), which is preferably also used to feed the product to (particularly through) a microfiltration device.

[0048] The mentioned static mixing devices can be designed in various ways and can include, for example, spiral, cubic or diamond-shaped mixers (provided with spiral, cubic or diamond-shaped product mixing walls) and / or the mentioned static mixing devices can be provided with through-flow spaces containing obstacles. The mixing devices can include, for example, dispersive or distributive mixing devices. It will be clear that the mixing devices can also be designed in various ways.

[0049] In a further aspect, the present invention relates to the use of a microfiltration wall in a microfiltration device of a foamed food product dispensing system configured to carry out the method of the present invention, to extend the operating life of the microfiltration device and / or reduce variability in foaming performance (i.e., have more consistent foaming performance). More particularly, the present invention relates to the use of a microfiltration wall in a foamed food product dispensing system comprising a microfiltration device, the dispensing system configured to carry out the method of the present invention, wherein the surface of the microfiltration wall in contact with the food product is hydrophobic, meaning that the surface has a contact angle with water greater than 110°, and the microfiltration wall has a porosity of 60% to 90% to extend the operating life of the microfiltration device and / or reduce variability in foaming performance.

[0050] Further refinements of the invention are set out in the dependent claims.The invention will now be elucidated on the basis of exemplary embodiments and drawings. [Brief explanation of the drawings]

[0051] [Figure 1] 1 shows a schematic diagram of a system according to a first exemplary embodiment of the present invention; [Figure 2] 1 shows a schematic diagram of an example of a microfiltration device. [Figure 3] 1 shows a schematic exploded side view of an assembled system according to a second exemplary embodiment of the present invention. [Figure 4] 4 shows a view similar to FIG. 3 of the operating device in the open position. [Figure 5] 4 shows a view similar to FIG. 3 of the product holder; [Figure 6] 10 shows an alternative refinement of the product holder. DETAILED DESCRIPTION OF THE INVENTION

[0052] Figure 1 shows a schematic diagram of an example of a product dispensing system, comprising a holder H for accommodating a product P to be dispensed, and a product discharge means (e.g., provided with a product discharge channel) for discharging the product P coming from the holder H. The system shown in Figure 1 can be used, for example, in assemblies such as those shown in Figures 3 to 5.

[0053] The holder H can be designed and formed in various ways. For example, the outer wall of the holder H can be made, for example, from a metal, an alloy, a plastic, etc. The outer wall can be of rigid or flexible design. The holder H can, for example, be of cylindrical or angular design or of a different design. The holder H can, for example, be designed to withstand a maximum internal pressure of, for example, 12 bar, in particular 10 bar, if the holder H is provided with a propellant (see below). According to an advantageous embodiment, the holder H is designed to withstand a significantly lower maximum pressure, for example, at most 2 bar, which allows the holder to have a relatively lightweight (and, for example, a relatively simple and low-cost) design.

[0054] According to an advantageous refinement, the food product P present in the holder is a foaming food product selected from creams, spray creams, (fruit) juices / drinks, alcoholic drinks or drink bases, such as beer or wine, dairy products or dairy-based drinks, such as whey drinks or permeate-based drinks, (milk) shakes, chocolate drinks, (drinking) yogurts, sauces, ice cream, desserts and juices. As shown in FIG. 1, the product discharge means 6 is advantageously provided with a microfiltration device 15, which is connectable (via a gas inlet 8) to a fluid supply 9, for example, for supplying gas to the product during product discharge. The microfiltration device 15 is further provided with a product inlet 15i for receiving the (not yet foamed) food product P (e.g., product P not yet containing gas) coming from the holder H and the discharge 6. The system shown in FIG. 1 can further be provided with regulating means 51, 52, for example, one or more operating valves, operating buttons, etc., for regulating the gas supply amount and / or gas pressure, as will be clear to those skilled in the art. For example, operable valve means can be provided for adjusting the amount of gas supplied (or the gas pressure) to the holder H. For example, operable valve means can be provided for adjusting the amount of gas supplied (or the gas pressure) to the microfiltration device 15. Preferably, the product discharge means 6 is further provided with an optional product treatment device, in this example comprising a mixing device 7 arranged downstream of the microfiltration device 15 for carrying out a mixing treatment on the product to which the gas is provided. More particularly, the mixing device is a static mixer 7. The product treatment device can also be designed in other ways. Preferably, this device is designed to allow a controlled (in particular gradual) reduction of the product overpressure, for example from superatmospheric pressure to a lower, substantially atmospheric pressure.

[0055] FIG. 2 shows a further, non-limiting refinement of the filtering device 15 in more detail. The microfiltration device 15 is provided with a (substantially closed) housing 15c, which includes, for example, a product inlet 15i for supplying a food product P, a gas inlet 8 for supplying a gas, and an outlet 15u for discharging the gas-treated product. The gas inlet 8 terminates in a gas-containing space 15d (i.e., the second space 15d), which is separated from the product inlet 15i and the outlet 15u by, for example, a rigid (particularly non-flexible) microfiltration wall 15a (which is provided with gas-permeable holes). Furthermore, the wall 15a separates the gas-supply space 15d from a product feed-through channel 15b (i.e., the first space 15b). The feed-through channel 15b extends between the product inlet 15i and the product outlet 15u (in the housing 15c) of the filtering device 15. The supply of product to / discharge from the channel 15b is indicated by arrows Q1 and Q2, respectively. As mentioned, the microfiltration device 15 can be designed in various ways. In particular, the microfiltration wall is preferably very rigid so that it does not deform under the influence of a pressure difference, e.g., a pressure difference of more than 1 bar, that prevails between the product feedthrough space 15b and the gas supply space 15d during use. In an exemplary embodiment, the product feedthrough channel 15b is within (or at least surrounded by) the microfiltration wall 15a, and the gas supply space 15d is outside the microfiltration wall 15a. Alternatively, the product feedthrough channel 15b is outside the microfiltration wall 15a, and the gas supply space 15d is formed by the space surrounded by this wall 15a. The microfiltration wall 15a is, for example, cylindrical, tubular, e.g., having a circular cross section, and provided with a hydrophobic layer 100.

[0056] According to further refinements, the length L of the wall 15a (particularly of the channel 15b) is at most 100 mm, preferably at most 50 mm, and most preferably at most 35 mm. This length L is, for example, in the range of about 4 to 50 mm (the minimum length is, for example, about 0.5 cm). In a relatively compact design, this length L is less than 35 mm, for example, about 5, 10, 20, 30, or 35 mm. The length L is, in particular, the length of the wall 15a measured in the product flow direction of the product during use flowing along this wall (parallel to this wall 15a) from the product inlet 15i to the product outlet 15u. The filtration device 15 (e.g., the microfiltration wall 15a) can have various dimensions and shapes, for example, flat, curved, conical, angular, straight, convex when viewed from the first space, concave when viewed from the first space, and / or combinations of these or other shapes. The morphology of the wall 15a may be, for example, homogeneous, sintered, cylindrically porous, sponge-like porous, asymmetrically constructed, constructed from several different layers, may include a combination of these configurations, or may be designed in different ways. The microfiltration wall 15a may itself be manufactured from various materials, such as ceramic materials, metals, plastics, polypropylene, polyolefins, blends, alloys, etc. The microfiltration wall 15a is preferably provided with relatively narrow air permeable holes (e.g., air permeable outflow channels, injection channels, having a gas outflow end terminating in the feed-through channel 15b) with an average pore diameter K, particularly having the characteristics described above.

[0057] The average wall thickness of the microfiltration wall 15a as a whole can be, for example, preferably 450 to 900 μm, more preferably 450 to 750 μm, and most preferably 450 to 550 μm. When the microfiltration wall 15a includes a hydrophobic layer, the layer preferably has an average thickness of 20 to 300 nm, more preferably 20 to 100 nm, and most preferably 20 to 50 nm. By way of non-limiting example, when the device 15 is tubular, the outer diameter of the tube of this filtration device 15 can be, for example, less than 10 cm, e.g., less than 1 cm.

[0058] Preferably, the microfiltration wall 15a is arranged, preferably concentrically, in a hollow housing 15c of the filtration device 15, coated with a hydrophobic layer 100 (see FIG. 2), and the housing is provided with a gas inlet 8. Between the inside of the housing 15c and the outside of the (in this case) tubular microfiltration wall 15a, there is a gap 15d for collecting the air supplied via the inlet 8. During use, the air present in the gap 15d preferably has a pressure higher than 1.2 bar, in particular higher than 5 bar, more particularly higher than 7 bar, for example in the range of 8 to 15 bar. The pressure of the product present during use in the flow-through space 15b is in particular lower than the pressure in the gap 15d (for example, by at least 1 bar lower or a lower pressure difference, for example, a pressure difference greater than 0 bar and less than 1 bar), so that the air present in the gap 15d uniformly enters the product through the pores (indicated by arrow T). In this way, fine air bubbles can be introduced uniformly into the product P for the purpose of foam formation.

[0059] The static mixer 7 can be designed in various ways: in particular, it has no moving parts, in contrast to dispersers with moving parts, such as, for example, turrax or rotor-stator mixers.

[0060] In particular, the system is provided with or can be connected to a gas supply for supplying gas under superatmospheric pressure to the microfiltration device 15, preferably also to the holder H. In FIG. 1 , the gas supply to the system is indicated by arrow Y. For example, to provide the gas supply, pumping means (e.g., having a compressor) and / or an overpressurized gas reservoir (e.g., a gas cylinder) may be provided. The system may, for example, comprise regulating means 51, 52 for regulating the flow rate and / or pressure of the gas to be supplied to the holder H and the filtering device 15. The supply, for example, comprises a supply line system 2, which, during use, comprises a line section connected to a suitable gas inlet 3 of the holder H and a line section connected to the filtering device 15 for supplying the filtering device 15 with gas during use. The gas may, for example, comprise one or more gases, gas mixtures, nitrogen, air, etc.

[0061] Optionally, the holder H is provided with a pressure relief valve (not shown) for reducing the pressure in the pressurized holder H.

[0062] The present exemplary embodiment is designed to supply the same gas to the holder H and the filtering device 15. Alternatively, the gas supply means can be designed, for example, to supply the holder with a first gas and the filtering device 15 with a second gas different from the first gas. Additionally, the system may be designed differently, for example to provide a product flow, for example by providing the system with pumping means for pumping the food product P from the holder H through an outlet.

[0063] 1 and 2 includes, for example, a method of dispensing a product P (e.g., a substantially gas-free product) coming from a holder H, where gas is supplied to the product P (flowing through feed-through channel 15b) via microfiltration device 15. In particular, microfiltration device 15 is operable to inject gas into the product P being supplied to the device.

[0064] Preferably, the product P supplied to the filtration device is not heated. The product may, for example, be cooled (for example to a temperature lower than the holder ambient temperature) or may have ambient temperature.

[0065] In another example, the product P supplied to the filtration device is heated (eg, to a temperature higher than the temperature at which the product has been stored, eg, a cold storage temperature, or higher than the holder ambient temperature).

[0066] The temperature of the gas (or gas mixture) to be fed to the filtration device can be, for example, ambient temperature, for example room temperature. The gas temperature can be, for example, in the range of 0 to 50°C, or another temperature, for example, higher than 50°C, or conversely, at or below 0°C.

[0067] Here, the essentially preferably not yet foamed food product P, for example, under the influence of gas supplied via the supply section 2, leaves the holder H, passes through the filtration device 15 via the discharge section 6, and then passes through the mixer 7. Here, the product is passed through, in particular, the tube interior space (i.e., the feed-through channel) 15b of the microfiltration device 15 (the product flows along the filtration wall 15a), and gas from the gas supply space 15d is injected into the product via (at least through) the microfiltration wall 15a for the purpose of foam formation in the product (for this purpose, gas is supplied from the gas supply space 15d to the pores). The pressure prevailing in the gas supply space 15d is, for example, higher than the pressure of the product P flowing along the filtration wall 15a. The flow rate of the product flowing through the filter 15 can be, for example, higher than 10 liters / hour, for example, in the range of about 30 to 600 liters / hour (e.g., 50 to 300 liters / hour), or another range as disclosed above.

[0068] Good results are obtained when the gas is introduced into the food product P through the filtering device 15 under the influence of a pressure of more than 2 bar, for example in the range higher than 5 bar, in particular higher than 7 or 8 bar, for example in the range of about 8 to 15 bar. The gas flow rate may, for example, be more than 10 liters per hour, for example in the range of about 30 to 600 liters / hour (for example 50 to 300 liters / hour, more particularly 100 to 300 liters / hour), or may have a different value. The ratio of product flow rate to gas flow rate may, for example, be in the range of 10:1 to 1:10.

[0069] Shortly thereafter (i.e., downstream of the microfiltration device 15), the food product P undergoes a mixing process, which is carried out by the static mixing device 7. It has been found that the food product coming from the mixer 7 (in FIG. 1 the product outlet via optional outlet line 66 is indicated by arrow Q4) can contain a particularly durable and stable foam that can be foamed particularly uniformly, for example, if the product itself is a foamable product. Furthermore, the system can be made to be particularly compact, durable, and of a relatively simple design to achieve such a result.

[0070] The present invention is further illustrated by the following non-limiting examples. [Example]

[0071] figure: FIG. 7 shows the experimental setup of the membrane foaming line used in the examples, including (1) raw material tank and water bath, (2) heating unit, (3) air line, (4) air pressure transmitter, (5) air flow meter, (6) raw material line, (7) raw material flow meter, (8) raw material pressure transmitter, (9) membrane holder, and (10) split junction.

[0072] Figure 8a shows 1) an SLA (stereolithography) printed double membrane module containing two parallel membranes with an effective length of 15 mm (each membrane module has an inner diameter of 4 mm), 2) a connecting tube with a length of 40 mm and an inner diameter of 2.5 mm, 3) a 12 cm SLA printed labyrinth, 4) a 40 mm outlet tube, 5) a tulip, and 6) a foaming chamber with a 1.5 mm diameter cream inlet restriction. FIG. 8b shows a foaming chamber with two parallel membranes, where the raw material and air are supplied independently.

[0073] Figures 9a-9d: Typical process parameter settings, typical uncoated HF membrane-foam properties (overrun [%], shape retention), and typical raw materials under process parameters (gas flow rate [L / min], cream flow rate [ml / min]).

[0074] 10a-10d: Photographs of toppings as a function of number of servings. The first serving is shown in FIG. 10a, the photograph in FIG. 10b was taken after 16 servings, the photograph in FIG. 10c was taken after 32 servings, and the photograph in FIG. 10d was taken after 55 servings.

[0075] Figures 11a to 11d: Plasma coated (Nanofics® 120) HF membrane - standard raw material at standard process parameter settings, including foam properties (shape retention, overrun [%]), process parameters (gas flow rate [L / min], cream flow rate [ml / min]) as a function of number of servings (= time).

[0076] Figures 12a and 12b: Overrun [%] and cream flow rate [ml / min] as a function of the number of servings for a standard raw material under standard process parameter settings using two plasma-coated C3F6 HF membranes (25 nm = light line, 50 nm = dark line).

[0077] Figures 13a-c show CSLM images of the outer skin of a virgin uncoated HF (HF = hollow fiber) membrane (Figure 13(a)), and of uncoated (Figure 13(b)) and coated (Figure 13(c)) membranes used in cream applications, respectively.

[0078] Figure 14: Fluorescence intensity of unfouled and fouled membranes stained with FITC (protein) and NR (fat): (1) unused uncoated HF, (2) unused uncoated HF used with cream, (3) unused coated HF, and (4) coated HF used with cream. (The dye reagent FITC is fluorescein isothiocyanate, and the dye reagent NR is the standard Eurodine dye "neutral red.")

[0079] Test configuration: The experiments were carried out in a laboratory line as shown in Figure 7. The solution to be foamed was placed in a pressure tank (10 L), which was placed in a bucket containing thermostatically regulated water (ice water for experiments with cream). The tank was then pressurized using air pressure from the internal gas system. The raw materials were supplied to the foaming module via two parallel feed lines containing flow meters and pressure gauges upstream of the foaming module. Air from the internal gas system was used to supply air to the foaming module via two parallel air lines, which also contained flow meters and pressure gauges upstream of the foaming module. The air had an estimated humidity of less than 5%.

[0080] The foaming chamber (as shown in Figure 8a) contained two parallel membranes, which were independently supplied with raw materials and air (see Figure 8b), and the foam emerging from the double membrane module merged into one connecting pipe and then flowed into an outlet structure or labyrinth with associated elements for shearing and structuring the cream foam.

[0081] Standard raw materials: The raw material liquid contained 28% fat by weight (27% milk fat + 1% vegetable fat (approximately a 1:1:1 mixture of sunflower oil, rapeseed oil, and palm oil)). It had a protein content of 2.1% by weight and a dry matter content of 41% by weight. The raw material was characterized by a viscosity of 150 mPa.s, a pH of 6.55, and a density of 1.0335 g / ml. Viscosity was measured using a Brookfield viscometer with spindle 62 at 30 rpm and 4-5°C.

[0082] Comparative Example 1 In the first experiment, a laboratory line foaming chamber was equipped with an uncoated HF (HF = hollow fiber) membrane. The HF membrane was a polypropylene membrane, e.g., 3M, MF-PP series, type S6 / 2 (see https: / / multimedia.3m.com / mws / media / 1673837O / 3m-capillary-membrane-mf-pp-series-type-s6-2-data-sheet.pdf), with a water contact angle of 97° (measured after immersion in water at 20°C for 3 days as described above) and a porosity of 69.7% (measured as described in the description above). Foam properties (shape retention, overrun [%]) and process parameters (gas flow rate [L min ]) were investigated while providing a complete bag-in-box (BIB). -1 The KPIs for the cream flow rate (ml / min) were monitored as a function of serving (= time). The total pressure on the container was fixed at 2.5 bar and the test rig was operated towards a set point of 140 ± 20% overrun. The graphs thus obtained (see Figures 9a-9d) show that the cream flow rate increased with increasing flow rate (from 0.36 to 0.50-0.45 mL min). -1 ), coupled with a steady decrease in gas flow (from 1.3 to 0.7 L min -1), whereas both overrun and shape retention decreased as a function of servings. Overrun decreased as less air was injected, and shape retention decreased as the shear force decreased when less air was injected. In addition, after 16 to 32 servings (i.e., after 2 to 4 hours), large air bubbles began to appear in the foam, which was unacceptable, and the low overrun and shape retention (values ​​below the minimum threshold of 120% and 15, respectively) caused the overall rejection of the cream topping (see Figures 10a-d).

[0083] Example 2: First, the same standard HF membranes used in Comparative Example 1 were plasma-coated with hepta-deca-fluorodecyl-acrylate (Nanofics® 120) to coating layer thicknesses of 150 nm and 300 nm, respectively. The HF membranes coated in this way had a water contact angle of 120° (measured after immersion in water at 20°C for 3 days as described above) and a porosity of 69.7% (determined as described in the above description). The membranes were then tested in a laboratory line using standard raw materials under standard parameter settings (i.e., the test rig was operated to a setting of 140±20% overrun, with the total pressure on the vessel fixed at 2.5 bar). The process performance was significantly improved compared to Comparative Example 1, i.e., no significant change in product quality was observed even after 7 days (overrun was stabilized at 140% and shape retention was somewhat constant at 20 (see Figure 11)). The gas flow rate was initially (1.4 to 1.2 L min -1 There was a tendency for the amount of oxygen to decrease, but it was 1.2L min -1 At a fixed flow rate, the flow rate leveled off and stabilized.

[0084] Similar results were obtained with both coating layer thicknesses.

[0085] Example 3: First, the same standard HF membrane used in Comparative Example 1 was plasma-coated with a different hydrophobic coating compared to that tested in Example 2. Instead of Nanofics® 120, 3-hexafluoropropylene (CF) was used as the coating, with coating thicknesses of 25 and 50 nm, respectively. The HF membrane thus coated had a water contact angle of over 120° (measured after immersion in water at 20°C for 3 days as described above) and a porosity of 69.7% (determined as described in the above description). The coated membrane was then tested in a laboratory line using standard raw materials under standard parameter settings (i.e., the process was operated to a setpoint of 140±20% overrun with the total vessel pressure fixed at 2.5 bar). Constant values ​​for overrun and cream flow rate were observed (see FIG. 12). Similar observations were made with different coating layer thicknesses.

[0086] Example 4: To understand the difference in behavior between coated and uncoated membranes with respect to protein and fat adsorption, the raw material components involved in the adsorption process were identified by analyzing several membranes (i.e., unused and used membranes, coated and uncoated HF membranes) using confocal laser scanning microscopy (CLSM). For this experiment, the same HF PP membrane as described in Comparative Example 1 was used. The same membrane as described in Example 3 was used as the coated HF membrane.

[0087] Figures 13a-c show CSLM images of the outer skin of a virgin, uncoated HF membrane compared to uncoated and coated membranes used in a cream application. The membranes were stained with 0.1% FITC at 5x magnification. The images are shown using the same settings, so intensity is a measure of protein concentration, allowing for a proper comparison of the degree of adsorption on the surface. More specifically, the images are shown so that the intensity of the observed staining is proportional to the protein content. The virgin membrane shows some protein spots, possibly due to handling of the membrane or the objective. The uncoated membrane used in the cream application shows an increase in intensity, indicating more protein adsorption on the membrane surface. The used, coated membrane shows only a slight increase in protein staining, indicating that the coating reduces protein adsorption.

[0088] Figure 14 shows the fluorescence intensity of virgin (coated and uncoated) PP membranes and membranes after use in cream applications. The virgin membranes were the benchmark and, as expected, showed almost no color intensity. The uncoated, cream-fouled membranes showed the highest protein loading, while the coated, cream-fouled membranes showed significantly lower protein loading but comparable fat content. CLSM samples show that all used samples exhibit significant fat deposition. The coated membranes show lower protein loading compared to the uncoated membranes. The different behavior of the coated and uncoated membranes, according to CLSM analysis, is attributed to differences in protein loading. In other words, proteins deposited on the membrane surface appear to be the main differentiating factor between coated and uncoated HF membranes in shortening their operational life and causing variations in foaming performance.

Claims

1. 1. A method for dispensing a foamed food product, comprising: the food product (P) is fed to a microfiltration device (15) provided with a microfiltration wall (15a) with gas-permeable pores separating a first space (15b) from a second space (15d), the food product (P) is passed through the first space (15b) and flows along the micro-filtration wall (15a) and the gas is fed into the second space (15d), or vice versa, so that the gas can be injected into the food product through the micro-filtration wall; - the food product has undergone an overrun ranging from 120 to 450%, the surface of the microfiltration wall (15a) on the side where the food product flows is hydrophobic, said surface having a contact angle with water of 110° or more; - said microfiltration wall (15a) is characterized in that it has a porosity of between 60% and 90%; method.

2. 2. The method according to claim 1, wherein the food product (P) undergoes a mixing treatment and / or a controlled pressure reduction downstream of the microfiltration device (15).

3. 2. The method of claim 1, wherein the food product (P) undergoes a mixing treatment upstream of the microfiltration device (15).

4. 4. The method according to any one of claims 1 to 3, wherein the microfiltration wall (15a) is a microfiltration wall having an asymmetric structure and an average pore size range of 0.1 to 5 microns, the more open side of the membrane preferably being the side through which the food product flows.

5. 5. The method according to claim 1, wherein the microfiltration wall (15a) is a hollow fiber membrane coated with a hydrophobic layer (100) so that the surface has a contact angle with water of 110° or more, and the microfiltration wall (15a) preferably comprises a support material selected from the group consisting of glass, metal, rubber, polymer and ceramic.

6. 6. The method of claim 5, wherein the hydrophobic layer (100) has an average thickness of 20 to 100 nm, and preferably the microfiltration wall (15a) together with the hydrophobic layer (100) has an average thickness of 450 to 900 μm.

7. The method according to claim 5 or 6, wherein said hydrophobic layer (100) comprises or consists of a material with a fluorocarbon backbone structure, such as hepta-deca-fluorodecyl-acrylate or hexa-fluoro-propylene.

8. 8. The method of any one of claims 5 to 7, wherein the hydrophobic layer (100) is applied to the membrane by one or more of the techniques selected from the group consisting of plasma coating, evaporation, chemical vapor deposition and dip coating.

9. A foamed food product dispensing system adapted to carry out the method according to any one of claims 1 to 8, comprising a holder (H) for accommodating a food product (P) to be dispensed and product discharge means (6) for discharging the food product coming from said holder (H), said product discharge means (6) being provided with a microfiltration device (15) provided with a product inlet (15i) for the supply of product, said microfiltration device (15) being connectable to a fluid supply (9) for supplying gas to said product during the product discharge, said product discharge means (6) preferably further comprising a treatment device, said treatment device being adapted to mix gas with the food product to which it is provided.

1. A foamed food product dispensing system, the foamed food product dispensing system being arranged downstream of the microfiltration device (15) for carrying out a combining and / or decompression treatment, the microfiltration device (15) being provided with a microfiltration wall (15a) having gas-permeable holes separating a gas supply space (15d) associated with the fluid supply from a product feed-through channel (15b) associated with the product inlet (15i), characterized in that the surface of the microfiltration wall (15a) on the side of the product feed-through channel (15b) is hydrophobic, the surface having a contact angle with water of 110° or more, and the microfiltration wall having a porosity of 60% to 90%.

10. 10. The foamed food product dispensing system according to claim 9, wherein the length (L) of said microfiltration wall (15a) is at least 5 mm and at most 10 cm, preferably at least 18 mm and at most 35 mm.

11. 11. The foamed food product dispensing system according to claim 9 or 10, wherein said microfiltration wall (15a) is a microfiltration wall with an asymmetric structure and an average pore size of 0.1 to 5 microns, the more open side of said membrane preferably being the side through which said food product flows.

12. 12. The foamed food product dispensing system according to any one of claims 9 to 11, wherein the microfiltration wall (15a) is a hollow fiber membrane coated with a hydrophobic layer (100), the microfiltration wall preferably comprising a support material selected from the group consisting of glass, metal, rubber, polymer and ceramic, the hydrophobic layer preferably comprising or consisting of a material having a fluorocarbon backbone structure such as hepta-deca-fluorodecyl-acrylate or hexa-fluoro-propylene.

13. 13. The foamed food product dispensing system according to any one of claims 9 to 12, wherein a gas supply is provided or connectable to the gas supply, which supplies gas under superatmospheric pressure to the microfiltration device (15).

14. 14. Use of a microfiltration wall (15a) in a foamed food product dispensing system comprising a microfiltration device (15) configured to carry out the method of any one of claims 1 to 13, wherein a surface of the microfiltration wall (15a) in contact with the food product is hydrophobic, said surface having a contact angle with water of 110° or more, and wherein the microfiltration wall (15a) has a porosity of 60% to 90% in order to extend the operating life of the microfiltration device (15) and / or reduce fluctuations in foaming performance.

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