Method and system for dispensing products

Abstract

The present invention relates to a method for dispensing a foamed food product, such as a cream or aerated dessert, using a microfiltration device comprising specific microfiltration walls. Furthermore, the present invention relates to a foamed food product dispensing system configured for carrying out such a method, and to the use of a specific microfiltration wall in a foamed food product dispensing system configured for carrying out such a method.

Description

Technical Field

[0001] The present invention relates to a method for dispensing a foamed food product (e.g. a cream or an aerated dessert) using a microfiltration device. Furthermore, the present invention relates to a foamed food product dispensing system configured for implementing such a method, and the use of a microfiltration wall in a foamed food product dispensing system configured for implementing such a method. Background Art

[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, WO2022 / 066019 discloses a foaming product dispensing system, wherein the system includes: a product dispensing machine configured to receive a replaceable product container; a product container configured to cooperate with the machine after being placed in the product dispensing machine; wherein the product container contains a foamable product, preferably a food product, such as cream, wherein the product container is provided with a product processing unit, the product processing unit including a foaming device having a product inlet for receiving the product and a product outlet for discharging the product, wherein the processing unit can be connected to a gas supply for supplying gas to the product, wherein the system is configured to dispense a foamed product with a predetermined expansion ratio greater than 200%.

[0004] EP2268173 discloses a method for dispensing a foamed product (P) (e.g. a food product), characterized in that the product is supplied to a microfiltration device, gas is supplied to the product (P) via the microfiltration device, and the product (P) undergoes a mixing process and / or a controlled decompression downstream of the microfiltration device.

[0005] US2020 / 360946 relates to a portable device for dispensing and foaming a product, the portable device comprising: a product container for containing a product to be foamed through and dispensed from the device; a gas container for containing at least a gas, wherein the gas substantially does not contain any greenhouse gases, such as N2O; a dispersion device having a product inlet connectable to the product container for receiving the product, the dispersion device further connectable to the gas container for supplying gas to the product during product discharge; a processing device downstream of the dispersion device for performing a mixing process and / or a decompression on the product provided with the gas; and a product dispensing head as part of the top section of the device and arranged downstream of the processing device.

[0006] JP2018-051483 provides a methane fermentation treatment device including a hollow fiber membrane module.

[0007] Further, WO2011 / 028117 discloses a system and method, by which a particularly stable foamed product is obtained in a particularly efficient manner with a relatively cheap, durable and relatively low-energy device, thereby achieving a constant product quality in particular. More particularly, it discloses a method for dispensing a foamed product, characterized in that a gas is supplied to the product via a microfiltration device, which is particularly used to introduce bubbles into the product in order to form a foamed and / or aerated product. Here, in particular, the product is supplied to the microfiltration device so as to be provided with gas. Therefore, the microfiltration device can achieve the formation of bubbles in the product. It is described that the microfiltration device particularly includes a rigid wall that separates the product feed-through space from the gas supply space. The filter wall (also represented as a membrane) is preferably provided with a large number of circulation channels (e.g., extending straight through this wall from the gas supply space to the product feed-through space), which are at least provided with a relatively narrow outflow portion (these channels can also be narrow channels each). However, it was found that the foaming performance degrades over time, which is obviously undesirable. Furthermore, it has been found that adsorption of proteins and / or fats onto the surface of the membrane and / or on the inside of the membrane pores leads to a shortened operating life of the membrane.

[0008] It is therefore an underlying object of the present invention to provide an improved foaming food product dispensing system comprising a microfiltration device, and a method for dispensing a foaming food product using such a dispensing system, wherein a more constant foaming performance is obtained and / or the operating life of the microfiltration device is extended. Summary of the invention

[0009] It was found that the above objects can be met by using a specific microfiltration wall in a foamed food product dispensing system comprising a microfiltration device. By using the specific microfiltration wall according to the invention, a particularly constant product quality of the foamed food product is achieved and / or the operating life of the microfiltration device is extended.

[0010] Therefore, in a first aspect, the present invention relates to a method for dispensing a foamed food product, characterized in that

[0011] - the food product is supplied to a microfiltration device provided with a microfiltration wall having gas permeable holes, the microfiltration wall separating the first space from the second space,

[0012] - wherein the food product is passed through the first space while flowing along the microfiltration walls and the gas is supplied to the second space, or vice versa, so that the gas can be injected into the food product via the microfiltration walls,

[0013] - wherein the food product undergoes an overrun rate in the range of 120%-450%,

[0014] - wherein the surface of the microfiltration wall on the side along which the food product flows is hydrophobic, said surface having a contact angle with water of 110° or more, and

[0015] - wherein the microfiltration wall has a porosity between 60% and 90%.

[0016] In another aspect, the present invention is directed to a foamed food product dispensing system configured for carrying out the method of the present invention.

[0017] In another aspect, the present invention relates to the use of the specific microfiltration wall of the present invention in a foaming food product dispensing system configured for implementing the method of the present invention so as to extend the operating life of the microfiltration device and / or reduce fluctuations in foaming performance, the foaming food product dispensing system comprising the microfiltration device.

[0018] Detailed description of the invention

[0019] In a first aspect, the invention relates to a method for dispensing a foamed food product, characterized in that

[0020] - the food product is supplied to a microfiltration device provided with a microfiltration wall having gas permeable holes, the microfiltration wall separating the first space from the second space,

[0021] - wherein the food product is passed through the first space while flowing along the microfiltration walls and the gas is supplied to the second space, or vice versa so that the gas can be injected into the food product via the microfiltration walls,

[0022] - wherein the food product undergoes an overrun rate in the range of 120%-450%,

[0023] - wherein the surface of the microfiltration wall on the side along which the food product flows is hydrophobic, said surface having a contact angle with water of 110° or more, and

[0024] - wherein the microfiltration wall has a porosity between 60% and 90%.

[0025] If the substrate has a contact angle of less than 90°, this means that water will tend to wet the surface of the substrate (i.e. it is hydrophilic), whereas in the case of a contact angle of greater than 90°, this means that water will tend not to wet the surface of the substrate (i.e. it is hydrophobic). The surface of the microfiltration wall according to the invention is superhydrophobic, which means that its surface has a contact angle with water of 110° or more. The microfiltration wall according to the invention preferably has a contact angle with water of at least 118°, more preferably at least 120° or more, most preferably at least 130° or more.

[0026] The contact angle of the substrate with water is defined as the contact angle with water measured after immersion in water at 20°C for 3 days. Suitable methods for measuring the contact angle of a surface with water will be apparent to those skilled in the art. One suitable method is to perform water contact angle measurements using a 3 μl drop of double distilled water and diiodomethane with a contact angle DATAPHYSICS OCA-2 goniometer managed by OCA-2 software.

[0027] The porosity of the microfiltration wall used according to the present invention has a porosity 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 in the membrane. The density of the membrane polymer and the liquid is derived from the literature, or if unknown in the literature, it can be determined using techniques known in the art. The mass of the membrane filled with liquid is measured using the "tap and weigh" method of gravimetric analysis. In the tap and weigh method, the membrane is immersed in a wetting fluid (in this case isopropanol) for 24 hours and weighed immediately after removing the fluid by tapping the surface and gently blowing away the liquid in the internal channel of the hollow fiber with compressed air. Repeatedly (3 repetitions) perform this process and measure the weight of the wet membrane and the dry membrane. By comparing the mass of the wet membrane and the dry membrane, the porosity of the membrane can be calculated using the following equation:

[0028]

[0029] Where m m = membrane mass, unit: g

[0030] m f = mass of fluid in the membrane, g

[0031] ρ m = Density of the membrane, in g / cm 3

[0032]

[0033] It is important that the porosity of the microfiltration wall according to the invention is between 60% and 90%, preferably between 70% and 90%, and most preferably between 75% and 90%. It has been found that if the porosity of the microfiltration wall is too low, the pressure build-up on the microfiltration wall is too high, which is undesirable. If the porosity of the membrane is greater than 90%, the mechanical strength of the membrane will be insufficient for practical use.

[0034] Preferably, the microfiltration wall used according to the invention has gas permeable pores having an average pore size K in the range of 0.1-5 microns, in particular having an average pore size of at least 0.2 microns (in particular greater than 0.3 microns) and less than 3 microns. Most preferably, the microfiltration wall is a microfiltration wall with an asymmetric structure and an average pore size range of 0.1-5 microns, most preferably an average pore size range of 0.1–2 microns. In the case of an asymmetric membrane, the more open side of the membrane is preferably on the side along which the food product flows. It has been found that such an arrangement has a beneficial effect on the operating pressure, which is particularly advantageous in the case where the product to be dispensed is more viscous.

[0035] Pore ​​size and pore size distribution are measured via gas liquid porometry (also known as capillary flow porometry (CFP)). This technique, generally known in the art, is based on displacing an inert and non-toxic wetting liquid embedded in a porous network by applying an inert pressurized gas. Therefore, only through-holes are measured. For asymmetric membranes, CFP is suitable for measuring the pore size and pore size distribution of the support layer, and these techniques are not sufficient to measure large surface pores. The size of the surface pores is determined by SEM.

[0036] More specifically, 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 liquid to fill at least all through-holes. An increased gas (nitrogen) pressure (P) is applied to one side of the sample. Liquid is expelled from each through-hole at a defined pressure according to the following equation depending on the size of the through-hole (hole diameter d):

[0037] P=(4γcosθ) / d

[0038] Where γ is the surface tension of the liquid, and θ is the contact angle between the liquid and the sample. The resulting gas flow through the pore is measured to determine the bubble point (point B, Fig.15 ; The figure shows the measured flow rate versus pressure data for the "wet" and "dry" processes; also shown are the calculated "semi-dry data" (dashed line), as well as the bubble point pressure 'B' and the pressure 'F' used to calculate the mean flow pore size) to calculate the maximum pore size.

[0039] A second data set of flow rate versus pressure relationships across the completely dry sample is used in conjunction with the wet flow data to calculate the mean flow pore size (F, Fig.16 ) and the pore size distribution. ( Fig.16The pore size distribution is shown as pore diameter as a function of flow rate. The maximum pores (the upper boundary of the pore size distribution) are determined by the flow rate at which the wet flow data are linearized (i.e., substantially equal to the dry flow rate). The pore size distribution is usually expressed as a cumulative flow rate (either as a percentage of the total or as volume per unit time) or as a differential flow rate, with the first derivative of the cumulative curve being given by Fig.16 as shown in .

[0040] CFP measurements were performed using a Porolux 500 instrument, a N2 flow rate of 100 ml / min and assuming a spherical shape of the pores and using Quantachrome Porofil as the wetting liquid. TM Wetting fluid (see https: / / www.quantachrome.com / porometer / porofil.html ) (with a fluid tension of 16 dyn / cm and contact angle = 0).

[0041] The expression "microfiltration wall with asymmetric structure" has the conventional meaning in the art, i.e. it is intended to represent any membrane having an anisotropic structure throughout its cross section (which means that the membrane has a uniform cross section compared to a microfiltration wall with a symmetric structure). Typically, an asymmetric membrane consists of a plurality of layers, each layer having a different structure and permeability. A typical anisotropic membrane has a relatively dense top layer, which is supported on a more open porous bottom layer. According to the present invention, the more open side of the membrane is preferably on the side along which the food product flows. The microfiltration wall itself can be made of different materials, as long as its surface has the desired static contact angle with water. 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 a desired contact angle with water of 110 ° or greater (measured as described in detail above). The hydrophobic layer is preferably applied to a supporting material, which is preferably selected from the group consisting of: glass, metal, rubber, polymer and ceramic. The hydrophobic layer preferably has an average thickness between 20 and 300 nm, more preferably between 20 and 100 nm, and most preferably between 20 and 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 between 450 and 900 μm, more preferably between 450 and 750 μm, and most preferably between 450 and 550 μm, the average thickness being measured using scanning electron microscopy (SEM). The hydrophobic layer preferably comprises or consists of a material having a fluorine-carbon backbone structure, such as perfluorodecyl acrylate or hexafluoropropylene.

[0042] Preferably, the microfiltration wall according to the invention is a hollow fiber membrane, which is coated with a hydrophobic layer as detailed above.

[0043] The hydrophobic layer may be applied to the microfiltration wall via any of the methods available in the art, such as, in particular, as described in NF Himma et al., "Progress in the Preparation and Application of Polypropylene Membranes" (Journal of Polymer Engineering 2016, 36(4), 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.

[0044] In the method according to the invention, the food product to be foamed is supplied to a microfiltration device provided with a microfiltration wall having gas permeable holes. The microfiltration wall separates the first space from the second space. The food product is passed through the first space while flowing along the microfiltration wall, and the gas is supplied to the second space so that the gas can be injected into the food product via the microfiltration wall (particularly via the permeable holes included in this wall), and as a result of the gas injection therein, the food product undergoes an expansion rate in the range of 120%-450%. As will be appreciated by the technician, the method can also be implemented in reverse, which means that the space through which the food product is passed can also be the second space, and the space supplied with gas can be the first space. The corresponding space can also be expressed as a product feed-through space (a space for feeding through the product) and a gas supply space. The product can be supplied to the product feed-through space by a suitable fluid supply device, and the gas can be supplied to the second space by a suitable gas supply device, which will be clear to the technician.

[0045] Thus, the method provided by the present invention provides a foamed food product very quickly and reliably in a hygienic manner. The method can be utilized on a small scale or, conversely, on a large scale. Furthermore, if the foamed food product formed by the present invention is intended for consumption, the product can provide a particularly pleasant mouthfeel.

[0046] As the technician will appreciate, the microfiltration device can be designed in various ways. Typically, the microfiltration wall separating the first space from the second space is sufficiently rigid. More particularly, the microfiltration wall is so rigid that under the influence of any pressure differential that may dominate between the first space and the second space during use, for example, greater than a pressure differential of 1 bar or a smaller pressure differential (the pressure mentioned in the present application is an absolute pressure), the wall is hardly deformed or even not deformed at all. The microfiltration device may include a single microfiltration wall, or may include two or more parallel microfiltration walls.

[0047] The microfiltration wall of the present invention can be, for example, cylindrical, for example, with a circular cross section. According to another detailed description, the length of the wall (particularly the length of the space (the food product is passed through the space when flowing along the microfiltration wall, as described above), the space is also represented as the product feed-through channel) is at most 10 cm (that is, 100 mm), particularly 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 length mentioned is, for example, in the range of about 5-50 mm. In a relatively compact design, this length L is less than 35 mm, for example, a length of about 5, 10, 20, 30 or 35 mm. Particularly preferred is a length of 18-33 mm.

[0048] The gas used according to the present invention may include one or more gases, preferably the gas is selected from the group consisting of: nitrogen, nitrogen oxide, carbon dioxide and air. Most preferably, the gas is air. The temperature of the gas (or gas mixture) to be supplied to the filtering device may be, for example, ambient temperature, such as room temperature. The gas temperature may be, for example, in the range of 0°C-50°C, or another temperature, for example, a temperature higher than 50°C, or conversely a temperature of 0°C or lower than 0°C.

[0049] The volume increase of a food product after foaming is typically expressed in terms of "percentage of expansion" or simply "expansion rate". The expansion rate gives the volume increase of the foamed product P relative to the volume of the non-foamed product and can be expressed as:

[0050] Expansion rate = ((W p_ W s ) / W s ) x 100%

[0051] Among them, W p represents the mass of a fixed volume of unfoamed product, and W s Indicates the mass of the same volume of foamed product. Therefore, an expansion percentage of 100% means that the volume of 100ml has increased to 200ml after dispensing.

[0052] With the method according to the invention, a desired overrun (degree of aeration) of a food product can be obtained, wherein the quality has a high consistency. For various foamable food products, a particularly high overrun (degree of aeration) can be obtained. The overrun is typically at least 120%. In the case of cream products, an overrun of between 135% and 450%, more preferably between 150% and 400%, is particularly preferred.

[0053] The food product to be foamed and dispensed according to the invention may be, for example, a cream, a spray cream, a (fruit) juice / beverage, an alcoholic beverage or beverage base (e.g. beer or wine), a dairy product or a dairy-based beverage (e.g. a whey beverage or a permeate-based beverage), a plant-based beverage (e.g. an oat-, soy-, coconut-, or almond-based beverage), a (milk) shake, a chocolate drink, a (drinking) yogurt, a sauce, an ice cream or a dessert. Preferably, in the present invention, no pre-foaming is utilized upstream of the filtration device, at least: a product which itself has not yet been foamed (i.e. a product which is in a substantially non-foamed state) is supplied to the microfiltration device.

[0054] Downstream of a microfiltration device, food products may experience:

[0055] - mixed processing; and / or

[0056] -Controlled decompression.

[0057] More particularly, in some embodiments, when the downstream product of the microfiltration device experiences a controlled pressure drop, this is advantageous. This is particularly advantageous in the case of a liquid with a higher viscosity than milk (e.g., cream), and preferably applies an operating pressure of at least 4 bar thereby. Here, the pressure of the product can particularly gradually reach a second pressure value from a first pressure value, wherein the first pressure value is higher than the second pressure value (the pressure difference between the first pressure and the second pressure can be a pressure difference of at least 1 bar or less). The first pressure can, for example, be superatmospheric pressure. The second pressure can, for example, be substantially atmospheric pressure. The pressure drop can be achieved by, for example, a product processing device (i.e., a pressure reducer, a pressure drop device) suitable for the purpose. The processing device can be configured to, for example, apply shear force to the flowing product to achieve the purpose of causing the pressure drop. When applying a gradual pressure drop, shear force is applied to the product in a controlled manner thereby, the separation of the product can be well prevented or limited.

[0058] It seems that good results are obtained, in particular for obtaining a homogeneous foamed product, if the product undergoes a mixing process downstream of the microfiltration device. Here, it is particularly advantageous when the mixing process is performed by a static mixing device. The mixing device can, for example, be a product processing device and seems to be able to achieve a pressure drop and shear forces on the product in a simple manner.

[0059] In some cases, it may be advantageous to supply gas to the product via the microfiltration device without utilizing a mixing process downstream (relative to the microfiltration device) and / or controlled decompression. In such an embodiment, the food product may undergo a mixing process upstream of the microfiltration device.

[0060] According to a further elaboration of the invention, gas can be introduced into the product via a microfiltration device under the influence of an (absolute) pressure greater than 1.2 bar, for example a pressure in a range greater than 5 bar, in particular above 7 bar, for example a pressure in a range of 8-15 bar.

[0061] The method may include, for example, using a product flow rate and a gas flow rate, wherein the ratio of the product flow rate to the gas flow rate is 10:1-1:10. The flow rate of the gas may, for example, be greater than 10 liters / hour, and may, for example, be in the range of about 30-600 liters / hour (e.g., 50-300 liters / hour, and more particularly 100-300 liters / hour), or have different values. The gas flow rate may, for example, be at least 7.7 liters / hour and at most 20.3 liters / hour.

[0062] In another aspect, the present invention relates to a foaming food product dispensing system configured for implementing the method of the present invention, wherein the system is provided with a holder for containing the food product to be dispensed, and product discharge devices for discharging the food product from the holder, wherein the product discharge devices are provided with microfiltration devices, the microfiltration devices are provided with a product inlet for supplying the product, wherein the microfiltration devices can be connected to a fluid supply for supplying gas to the product during product discharge, wherein the product discharge devices are preferably further provided with a processing device, which is arranged downstream of the microfiltration devices for performing a mixing process and / or a decompression process on the food product provided with the gas, wherein the microfiltration device is provided with a microfiltration wall with gas permeable holes, the microfiltration wall separating a gas supply space associated with the fluid supply from a 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 contact angle of the surface with water is 110° or more, and wherein the microfiltration wall has a porosity between 60% and 90%.

[0063] In this way, the advantages mentioned above can be achieved.

[0064] As the skilled person understands, the preferred embodiments set out in detail above for the method according to the invention apply mutatis mutandis to the foamed food product dispensing system of the invention.

[0065] The foamed food product dispensing system may be provided with a product processing device, such as a mixing device, in particular a static mixer, in which case the product processing device is arranged downstream of the microfiltration device. The product processing device may perform a mixing process in order to mix the foamed food product and / or subject the foamed food product to a controlled pressure drop, in particular for generating a uniformly foamed food product.

[0066] The foamed food product dispensing system according to the present invention is simple to use, relatively fast, relatively reliable and robust (preferably without moving parts), easily cleanable and hygienic, while maintaining quality. Additionally, the system can be scaled well; the system can be of relatively small design (e.g., a microfiltration device with a maximum dimension (e.g., length) less than 35 mm) or conversely of relatively large design (e.g., a microfiltration device with a maximum dimension (e.g., length) of 10-20 cm).

[0067] The product processing device mentioned (e.g. a static mixing device) can be designed in various ways. According to a further elaboration, this product processing device is designed to agitate the product flowing through this device (provided with air bubbles) and / or change its course (i.e. accelerate it, with the direction of the product velocity vector preferably changing a number of times). The product processing device is in particular not provided with moving parts and can mix the product in a passive manner.

[0068] The product processing device referred to (e.g., a static mixing device) can, for example, be designed to maintain a substantially static obstacle (e.g., a substantially circular obstacle, a ball, a marble, a flow rate influencing wall or the like) in the flow path of the product in order to process the product (and in particular to cause it to travel through the product processing device along one or more non-straight paths).

[0069] The product provided with gas bubbles can be pushed through / along the product processing device under the influence of a fluid pressure suitable therefor (particularly superatmospheric pressure), for example. This fluid pressure is preferably also utilized to supply the product to (and in particular through) the microfiltration device.

[0070] The mentioned static mixing devices can be designed in different ways and for example comprise spiral, cubic or rhomboid mixers (provided with spiral, cubic or rhomboid product mixing walls) and / or be provided with a throughflow space containing obstacles. The mixing device can for example comprise a decentralized or distributed mixing device. It will be clear that the mixing device can also be designed differently.

[0071] In another aspect, the present invention relates to the use of a specific microfiltration wall in a microfiltration device of a foaming food product dispensing system configured for implementing the method of the present invention, in order to extend the operating life of the microfiltration device and / or reduce fluctuations in the foaming performance (i.e., to have a more constant foaming performance). More particularly, the present invention relates to the use of a microfiltration wall in a foaming food product dispensing system comprising a microfiltration device, the dispensing system being configured for implementing the method of the present invention, wherein the surface of the microfiltration wall in contact with the food product is hydrophobic, meaning that the contact angle of the surface with water is greater than 110°, and wherein the microfiltration wall has a porosity between 60% and 90%, in order to extend the operating life of the microfiltration device and / or reduce fluctuations in the foaming performance.

[0072] Further elaborations of the invention are described in the subclaims. At present, the invention will be explained based on exemplary embodiments and the accompanying drawings. In the drawings:

[0073] Figure 1 shows a schematic diagram of a system according to a first exemplary embodiment of the present invention;

[0074] Figure 2 An example of a microfiltration device is schematically shown;

[0075] Figure 3 shows a schematic exploded side view of an assembled system according to a second exemplary embodiment of the present invention;

[0076] Figure 4 shows an operating device similar to Figure 3 , the operating device is in an open position;

[0077] Figure 5 shows a product holder similar to Figure 3 's view;

[0078] Figure 6 An alternative elaboration of a product holder is shown.

[0079] Non-limiting exemplary embodiments

[0080] Figure 1 An example of a product dispensing system is schematically shown, which includes a holder H for accommodating a product P to be dispensed, and a product discharging device (e.g., provided with a product discharging channel) for discharging the product P from the holder H. For example, in Figures 3 to 5 or otherwise utilize the components represented in Figure 1 The system shown in .

[0081] The holder H can be designed and formed in different ways. For example, the outer wall of the holder H can be made of, for example, metal, alloy, plastic or the like. The outer wall can have a rigid or flexible design. The holder H can, for example, have a cylindrical or angular design, or have a different design. For example, if the holder H is provided with a propellant (see below), the holder H can be designed to withstand a maximum internal pressure of, for example, 12 bar, in particular 10 bar. According to an advantageous embodiment, the holder H is designed to withstand a significantly lower maximum pressure (for example, at most 2 bar), so that the holder can have a relatively light (and, for example, relatively simple, cheap) design.

[0082] According to an advantageous elaboration, the food product P present in the holder is a foamable food product selected from the group consisting of: cream, sprayed cream, (fruit) juice / beverage, alcoholic beverage or beverage base (e.g. beer or wine), dairy product or dairy-based beverage (e.g. whey beverage or permeate-based beverage), (milk) shake, chocolate drink, (drinking) yoghurt, sauce, ice cream, dessert and juice. Figure 1 As shown in , the product discharge device 6 is advantageously provided with a microfiltration device 15, which can for example be connected (via the gas inlet 8) to a fluid supply 9 for supplying gas to the product during product discharge. In addition, the microfiltration device 15 is provided with a product inlet 15i for receiving the (not yet foamed) food product P (e.g. a product P that does not yet contain gas) from the holder H and the discharge member 6. Figure 1 The system shown in the figure can be further provided with regulating devices 51, 52, such as one or more operating valves, operating buttons and / or the like, for example, for regulating the gas supply and / or gas pressure, which will be clear to the technician. An operable valve device can be provided, such as for regulating the gas supply (or gas pressure) to the retainer H. An operable valve device can be provided, such as for regulating the gas supply (or gas pressure) to the microfiltration device 15. Preferably, the product discharge device 6 is further provided with an optional product processing device, including a mixing device 7 in this example, which is arranged downstream of the microfiltration device 15 for performing a mixing process on the product provided with gas. More particularly, the mixing device is a static mixer 7. The product processing device can also be designed in other ways. Preferably, this device is designed so that the excess pressure of the product can be reduced from, for example, superatmospheric pressure in a controlled manner (especially gradually) to a lower substantially atmospheric pressure.

[0083] Figure 2A further non-limiting elaboration of the filter device 15 is shown in more detail. The microfiltration device 15 is, for example, provided with a (substantially closed) housing 15c, which comprises a product inlet 15i for supplying food products P, a gas inlet 8 for supplying gas, and an outlet 15u for discharging a product provided with gas. The gas inlet 8, for example, terminates in a gas receiving space 15d (i.e., the second space 15d), which is separated from the product inlet 15i and the outlet 15u by a rigid (particularly, non-flexible) microfiltration wall 15a (provided with gas permeable holes). In addition, the wall 15a separates the gas supply space 15d from the 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 filter device 15. The product supply to the channel 15b / discharging the product from the channel is indicated by arrows Q1, Q2, respectively. As mentioned, the microfiltration device 15 can be designed in various ways. In particular, the microfiltration wall is preferably so rigid that the wall does not deform under the influence of the pressure difference (e.g., a pressure difference greater than 1 bar) that prevails between the product feed-through space 15b and the gas supply space 15d during use. In an exemplary embodiment, the product feed-through channel 15b is located in the microfiltration wall 15a (at least surrounded by the wall), and the gas supply space 15d is located outside it. Alternatively, the product feed-through channel 15 is located 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, having, for example, a circular cross-section, and includes a hydrophobic layer 100.

[0084] According to further elaboration, the length L of the wall 15a (in particular, the length of the channel 15b) is at most 100 mm, preferably at most 50 mm, most preferably at most 35 mm. This length L is, for example, in the range of about 4-50 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, a length of about 5, 10, 20, 30 or 35 mm. In particular, the length L is the length of the wall 15a measured along the product flow direction of the product during use, the product flowing along this wall (parallel to this wall 15a) from the product inlet 15i to the product outlet 15u. The filter device 15 (e.g., the microfiltration wall 15a) can also be differently sized and shaped, for example flat, curved, conical, angular, straight, convex (viewed from the first space), concave (viewed from the first space), and / or a combination of these shapes or other shapes. The morphology of the wall 15a can be, for example, uniform, sintered, cylindrically porous or sponge-like porous, asymmetrically constructed, constructed from several different layers, can include a combination of these configurations or be designed in different ways. The microfiltration wall 15a itself can be made of different materials, such as ceramic materials, metals, plastics, polypropylene, polyolefins, blends, alloys or the like. The microfiltration wall 15a is preferably provided with relatively narrow air permeable holes (e.g., air permeable outflow channels, injection channels, with a gas outflow end terminating in the feed-through channel 15b), in particular with an average pore size K with the characteristics as described above.

[0085] The average wall thickness of the microfiltration wall 15a may be, for example, preferably between 450 and 900 μm, more preferably between 450 and 750 μm, and most preferably between 450 and 550 μm in general. When the microfiltration wall 15a comprises a hydrophobic layer, the layer preferably has an average thickness between 20 and 300 nm, more preferably between 20 and 100 nm, and most preferably between 20 and 50 nm. According to a non-limiting example, if the device 15 is tubular, the outer diameter of the tube of this filtering device 15 may be, for example, less than 10 cm, for example less than 1 cm.

[0086] Preferably, the microfiltration wall 15a is preferably concentrically arranged in the hollow housing 15c of the filtration device 15 and is coated with a hydrophobic layer 100 (see Figure 2), the housing being provided with a gas inlet 8. Between the interior of the housing 15c and (in this case) the exterior of the tubular microfiltration wall 15a is a void 15d for collecting air supplied via the inlet 8. During use, the air present in the void 15d preferably has a pressure higher than 1.2 bar, in particular higher than 5 bar, more in particular higher than 7 bar, for example a pressure in the range of 8-15 bar. The pressure of the product present in the circulation space 15b during use is in particular lower than the pressure in the void 15d (for example, lower by at least 1 bar, 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 void 15d enters the product uniformly via the pores (this is indicated by arrows T). In this way, fine air bubbles can be uniformly introduced into the product P for the purpose of forming foam.

[0087] The static mixer 7 can be designed in different ways. In particular, a static mixer is not provided with moving parts, in contrast to, for example, a disperser (such as a turrax or rotor-stator mixer) which is provided with moving parts.

[0088] In particular, the system is provided with or connectable to a gas supply for supplying gas at superatmospheric pressure to the microfiltration device 15 and preferably also to the holder H. The gas supply to the system is Figure 1 Indicated by arrow Y. A pumping device (e.g., with a compressor) and / or a gas reservoir (e.g., a gas cylinder) reaching excess pressure may be provided, for example, to achieve gas supply. The system may include, for example, regulating devices 51, 52 for regulating the flow rate and / or pressure of the gas to be supplied to the holder H and the filter device 15. The supply member includes, for example, a supply line system 2, which is provided with a line portion connected to a suitable gas inlet 3 of the holder H during use, and a line portion connected to the filter device 15 during use to supply gas thereto. The gas may include, for example, one or more gases, a gas mixture, nitrogen, air or the like.

[0089] Optionally, the holder H is provided with a pressure release valve (not shown) for making the pressure of the pressurized holder H smaller.

[0090] 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 may be designed, for example, to supply a first gas to the holder and a second gas, different from the first gas, to the filtering device 15. In addition, the system may be designed, for example, in a different manner to achieve product flow, for example by providing the system with pumping means to pump the food product P from the holder H through the discharge.

[0091] Figure 1 to Figure 2Uses of the system shown in include, for example, a method for dispensing a product P (e.g., a substantially gas-free product) from a holder H, wherein gas is supplied to the product P (flowing through a feed-through channel 15b) via a microfiltration device 15. In particular, the microfiltration device 15 operates to inject gas into the product P supplied to the device.

[0092] Preferably, the product P supplied to the filtering device is not heated. The product may for example be cooled (eg to a temperature below the temperature of the holder environment), or have ambient temperature.

[0093] In another example, the product P supplied to the filtering 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 temperature of the holder environment).

[0094] The temperature of the gas (or gas mixture) to be supplied to the filtering device may be, for example, ambient temperature, such as room temperature. The gas temperature may be, for example, in the range of 0°C-50°C, or another temperature, such as a temperature above 50°C, or conversely 0°C or below 0°C.

[0095] Here, for example, under the influence of the gas supplied via the supply 2, the food product P, which itself is preferably not yet foamed, passes out of the holder H to be guided through the filter device 15 via the discharge 6 and then through the mixer 7. Here, the product is in particular passed through the tube inner space (i.e., the feed-through channel) 15b of the microfiltration device 15 (in the case of a product flow along the filter wall 15a), while the gas from the gas supply space 15d is injected into the product via the microfiltration wall 15a (at least through this wall) for the purpose of forming bubbles in the product (for this purpose, the gas is supplied from the gas supply space 15d to the holes). The pressure prevailing in the gas supply space 15d is, for example, higher than the pressure of the product P flowing along the filter wall 15a. The flow rate of the product flowing through the filter 15 can be, for example, higher than 10 liters / hour and, for example, in the range of about 30-600 liters / hour (e.g., 50-300 liters / hour), or in another range as disclosed above.

[0096] Good results are obtained if the gas is introduced into the food product P via the filtering device 15 under the influence of a pressure greater than 2 bar, for example a pressure in the range of greater than 5 bar, in particular a pressure greater than 7 or 8 bar, for example a pressure in the range of about 8-15 bar. The flow rate of the gas may be, for example, greater than 10 liters / hour and may be, for example, in the range of about 30-600 liters / hour, for example, 50-300 liters / hour, and more particularly 100-300 liters / hour, or have different values. The ratio of the product flow rate to the gas flow rate may, for example, be in the range of 10:1-1:10.

[0097] Thereafter (ie downstream of the microfiltration device 15), the food product P undergoes a mixing process which is performed by the static mixer 7. It has been found that the food product from the mixer 7 (the product outflow via the optional outflow line 66) Figure 1 In the embodiment of the present invention, the foam (indicated by arrow Q4 in the figure) can contain a particularly durable, stable foam, which can, for example, be particularly uniformly foamed if the product itself is a foamable product. In addition, the system can be made of a particularly compact, durable and relatively simple design to obtain such a result.

[0098] The present invention is further illustrated by the following non-limiting examples:

[0099] Example

[0100] Attached photos:

[0101] Figure 7 The experimental setup of the membrane foaming line used in these examples is shown, which has (1) a feed tank and water bath, (2) a heating unit, (3) an air line, (4) a pressure transmitter for air, (5) an air flow meter, (6) a feed line, (7) a feed flow meter, (8) a pressure transmitter for feed, (9) a membrane holder, and (10) a flow splitter junction;

[0102] Figure 8a shows a foaming chamber with: 1) SLA (stereolithography) printed dual membrane module containing 2 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, 6) a 1.5 mm diameter cream inlet restriction;

[0103] FIG8 b shows a foaming chamber with two parallel membranes which are independently supplied with feed and air;

[0104] Figure 9a to Figure 9d: Standard feed under standard process parameter settings, standard uncoated HF film - foam properties (overrun [%], firmness), process parameters (gas flow [L / min], cream flow [ml / min]);

[0105] Figures 10a to 10d: photographs of toppings according to number of servings, wherein Figure 10a depicts the first serving; the photograph of Figure 10b was taken after 16 servings; the photograph of Figure 10c was taken after 32 servings; and the photograph of Figure 10d was taken after 55 servings.

[0106] Fig.11a to Fig.11d : Standard feed under standard process parameter settings, with plasma coating ( 120) HF films - foam properties (firmness, overrun [%]), process parameters (gas flow [L / min], cream flow [ml / min]) according to number of portions (= time).

[0107] Fig. 12a-b: Standard feed at standard process parameter settings with two plasma coated C3F6HF membranes (25 nm = light line; 50 nm = dark line); overrun [%]) and cream flow [ml / min]) as a function of number of portions are depicted.

[0108] Figures 13a-13c show CSLM images of the outer layer of an unused uncoated HF (HF = hollow fiber) membrane (Figure 13(a)) and a membrane used in a cream application, uncoated (Figure 13(b)) and coated (Figure 13(c)), respectively.

[0109] Fig.14 : Fluorescence intensity of unstained membranes and stained membranes stained with FITC (protein) and NR (fat): (1) unused uncoated HF, (2) uncoated HF with cream, (3) unused coated HF, (4) coated HF with cream. (Dye reagent FITC is fluorescein isothiocyanate; dye reagent NR is "neutral red", a standard diaminoazine dye).

[0110] Test setup:

[0111] The experiments were performed on the lab-line, such as Figure 7As shown in . The solution to be foamed is placed in a pressure tank (10 L) which is placed in a bucket with constant temperature water (ice water for cream experiments). The tank is then pressurized using air pressure from an internal gas system. The feed is supplied to the foaming module via 2 parallel feed lines, which include a flow meter and a pressure gauge upstream of the foaming module. Air is supplied to the foaming module via 2 parallel air lines using air from an internal gas system, which include a flow meter and a pressure gauge upstream of the foaming module. The estimated humidity of the air is <5%).

[0112] The foaming chamber (as depicted in Figure 8a) comprises two parallel membranes; these two membranes are independently supplied with feed and air (see Figure 8b), and the foam leaving the double membrane module merges into a connecting pipe, followed by an outlet geometry or labyrinth and accompanied by elements for shearing and structuring the cream foam.

[0113] Standard feed:

[0114] The feed solution contained 28 wt% fat (27 wt% milk fat + 1 wt% vegetable fat, which is an approximately 1:1:1 mixture of sunflower oil, rapeseed oil and palm oil). It had a protein content of 2.1 wt%, a dry matter content of 41 w%. The feed was characterized by a viscosity of 150 mPa.s, a pH of 6.55, and a density of 1.0335 g / ml. The viscosity was measured using a Brookfield viscometer with spindle 62 at 4°C-5°C at 30 rpm.

[0115] Comparative Example 1

[0116] In a first experiment, the foaming chamber of the lab line was equipped with an uncoated HF (HF=hollow fiber) membrane. The HF membrane was a polypropylene membrane sold directly from 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 ), whose contact angle with water (measured after immersion in water at 20° C. for 3 days, as described above) was 97° and whose porosity (determined as described above in the specification) was 69.7%. On the complete BiB (bag in box), the foam properties (firmness, overrun [%]) and the process parameters (gas flow [L min -1 The test apparatus was turned to a set point of 140% ± 20% overrun and the total pressure on the vessel was fixed at 2.5 bar. The graphs thus obtained (see Figures 9a to Figure 9d ) shows a steady decrease in gas flow rate (from 1.3 to 0.7 L min -1) plus the increase in cream flow (from 0.36 to 0.50-0.45 mL min -1 ), while both overrun and firmness decreased with the number of servings. Overrun decreased as less air was injected, and firmness decreased as shear force decreased when less air was injected. In addition, large bubbles began to appear in the foam after 16-32 servings (i.e., after 2-4 hours), which was unacceptable - the low overrun and firmness (values ​​below the minimum threshold of 120% and 15, respectively) also contributed to the overall rejection of the cream topping (see Figures 10a to 10d).

[0117] Example 2:

[0118] First, the same standard HF film as used in Comparative Example 1 was coated with perfluorodecyl acrylate ( 120) were plasma coated with a coating thickness of 150 nm and 300 nm, respectively. The contact angle of the coated HF membrane with water (measured after immersion in water at 20°C for 3 days, as described above) was 120° and the porosity (determined as described above in the description) was 69.7%. Subsequently, these membranes were tested in the lab line under standard parameter settings with standard feed (i.e. the test apparatus was turned to a set point of 140% ± 20% expansion and the total pressure on the vessel was fixed at 2.5 bar). Compared with control example 1, the process performance was significantly improved, i.e. even after 7 days, no significant changes in the product quality were observed (expansion was stable at 140%, firmness more or less constant at 20) (see Figure 11). Although the gas flow rate initially tended to decrease (from 1.4 to 1.2 L min -1 ), but it stabilized and remained stable at 1.2 L min -1 of fixed flow.

[0119] Similar results were obtained in the case of both coating thicknesses.

[0120] Example 3:

[0121] Compared to those membranes tested in Example 2, the same standard HF membranes as used in Comparative Example 1 were first plasma coated with another hydrophobic coating; namely, 3-hexafluoropropylene (C3F6) was used as a coating in place of 120; coating thicknesses of 25 and 50 nm, respectively. The contact angle of the coated HF membrane with water (measured after immersion in water at 20°C for 3 days, as described above) was greater than 120° and the porosity (determined as described above in the description) was 69.7%. Subsequently, these coated membranes were tested in the lab line with standard feed and under standard parameter settings (i.e. the process was turned to a set point of 140% ± 20% expansion and the total pressure on the vessel was fixed at 2.5 bar). Constant values ​​of expansion and cream flow were observed (see Figure 12). Similar observations were made in the case of different coating thicknesses.

[0122] Example 4:

[0123] In order to understand the differences in behavior between coated and uncoated membranes in terms of protein and fat adsorption, the feed components involved in the adsorption process were identified by analyzing several membranes (i.e., unused and used membranes, coated HF membranes and uncoated HF membranes) with confocal laser scanning microscopy (CLSM). For this experiment, the same HF PP membrane as described in Control Example 1 was used. As coated HF membrane, the same membrane as described in Example 3 was used.

[0124] Figures 13a to 13c show CSLM images of the outer layer of an unused, uncoated HF membrane compared to an uncoated and coated membrane that has been used in a cream application. The membrane was stained with 0.1% FITC (magnification of 5X). The images were shown using the same settings, so the intensity is a measure of the protein concentration, allowing a proper comparison of the degree of adsorption on the surface. More specifically, the images are shown in such a way that the intensity of the observed staining is proportional to the protein content. The unused membrane shows some protein spots, which may be due to the treatment of the membrane or the objective lens. The uncoated membrane used in the cream application shows an increased intensity, which indicates a large amount of protein adsorption on the membrane surface. The coated membrane used only shows a slight increase in protein staining, which indicates that the coating reduces protein adsorption.

[0125] Fig.14Unused PP films (coated and uncoated) and the fluorescence intensity of these films after use in cream applications are shown. Unused films are benchmarks and hardly show any color intensity as expected. Uncoated cream contaminated films show the highest protein loading, while coated cream films show significantly lower protein loading, but fat content is comparable. CLSM samples reveal that all samples used show significant fat adhesion. Compared with uncoated films, coated films show lower protein loading. According to CLSM analysis, the different behaviors of coated films and uncoated films are attributed to the differences in protein loading. In other words, the protein attached to the film surface seems to be the main distinguishing factor in shortening the film operating life and producing foaming performance fluctuations in coated HF films and uncoated HF films.

Claims

1. A method for dispensing a foamed food product, characterized in that - the food product (P) is supplied to a microfiltration device (15) provided with a microfiltration wall (15a) having gas permeable holes, which separates a first space (15b) from a second space (15d), - wherein the food product (P) is passed through the first space (15b) while flowing along the microfiltration wall (15a), and gas is supplied to the second space (15d), or vice versa so that the gas can be injected into the food product via the microfiltration wall, - wherein the food product undergoes an overrun in the range of 120%-450%, and - wherein the surface of the microfiltration wall (15a) on the side along which the food product flows is hydrophobic, the contact angle of said surface with water being 110° or greater, and - wherein the microfiltration wall (15a) has a porosity between 60% and 90%.

2. The method of claim 1, wherein: The food product (P) undergoes a mixing process and / or a controlled decompression downstream of the microfiltration device (15).

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

4. A method as claimed in any one of the preceding claims, wherein: The microfiltration wall (15a) is a microfiltration wall with an asymmetric structure and an average pore size range of 0.1-5 microns, wherein the more open side of the membrane is preferably on the side along which the food product flows.

5. A method as claimed in any one of the preceding claims, wherein: The microfiltration wall (15a) is a hollow fiber membrane coated with a hydrophobic layer (100) so that the contact angle of the surface with water is 110° or greater, and the microfiltration wall (15a) preferably comprises a supporting material selected from the group consisting of glass, metal, rubber, polymer and ceramic.

6. The method of claim 5, wherein: The hydrophobic layer (100) has an average thickness between 20 and 300 nm, and wherein, preferably, the microfiltration wall (15a) together with the hydrophobic layer (100) has an average thickness between 450 and 900 μm.

7. The method according to claim 5 or 6, wherein: The hydrophobic layer (100) comprises or consists of a material having a fluorine-carbon backbone structure, such as perfluorodecyl acrylate or hexafluoropropylene.

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

9. A foamed food product dispensing system configured for carrying out the method of any one of the preceding claims, wherein: The system is provided with a holder (H) for containing a food product (P) to be dispensed, and product discharge devices (6) for discharging the food product from the holder (H), wherein the product discharge devices (6) are provided with microfiltration devices (15) provided with a product inlet (15i) for supplying the product, wherein the microfiltration devices (15) are connectable to a fluid supply (9) for supplying gas to the product during product discharge, wherein the product discharge devices (6) are preferably further provided with a processing device, which is arranged downstream of the microfiltration devices (15). For performing a mixing process and / or a decompression process on a food product provided with gas, wherein the microfiltration device (15) is provided with a microfiltration wall (15a) having a gas permeable hole, the microfiltration wall separating a gas supply space (15d) associated with the fluid supply member from a product feed 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 channel (15b) is hydrophobic, the contact angle of the surface with water is 110° or greater, and wherein the microfiltration wall has a porosity between 60% and 90%.

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

11. A foamed food product dispensing system as claimed in claim 9 or 10, wherein: The microfiltration wall (15a) is a microfiltration wall with an asymmetric structure and an average pore size of 0.1-5 microns, wherein the more open side of the membrane is preferably on the side along which the food product flows.

12. A foamed food product dispensing system as claimed in any one of claims 9 to 11, wherein: The microfiltration wall (15a) is a hollow fiber membrane coated with a hydrophobic layer (100), wherein the microfiltration wall preferably comprises a supporting material selected from the group consisting of: glass, metal, rubber, polymer and ceramic, and wherein the hydrophobic layer preferably comprises or consists of a material having a fluorine-carbon backbone structure, such as perfluorodecyl acrylate or hexafluoropropylene.

13. A foamed food product dispensing system according to any one of claims 9 to 12, provided with or connectable to a gas supply for supplying gas to the microfiltration device (15) at superatmospheric pressure.

14. Use of a microfiltration wall (15a) in a foamed food product dispensing system comprising a microfiltration device (15), the foamed food product dispensing system being configured to implement a method as claimed in any one of the preceding claims, characterized in that The surface of the microfiltration wall (15a) in contact with the food product is hydrophobic, having a contact angle with water of 110° or greater, and wherein the microfiltration wall (15a) has a porosity between 60% and 90% in order to extend the operating life of the microfiltration device (15) and / or reduce fluctuations in foaming performance.

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