Gas injection extrusion for the preparation of infant formula products

Abstract

The present invention relates to a method for preparing an infant formula product, comprising: (a) subjecting an aqueous mixture having a protein component and a carbohydrate component to a heat treatment step; (b) mixing the aqueous mixture with a lipid component; (c) subjecting the aqueous mixture comprising the lipid component, the carbohydrate component and the heat-treated protein component to a homogenization and emulsification step to obtain a homogenized water-in-oil emulsion having a total solid content of 45-80% by weight; (d) delivering the homogenized emulsion to an extruder, independently adding digestible carbohydrates and optional dietary fiber to the extruder, and extruding the contents of the extruder to obtain an extruded aerated material, wherein a gas is injected into the extruder; (e) preparing an infant formula product from the extruded aerated material. The present invention also relates to an infant formula product obtainable by the method of the present invention and a modular system suitable for carrying out the method of the present invention.

Description

Technical Field

[0001] The present invention relates to a process for preparing a nutritional composition, in particular an infant formula product thereof, by extrusion, to the nutritional composition thus obtained and to a modular system suitable for carrying out the process of the invention. Background Art

[0002] Powdered nutritional compositions containing a protein component, a fat component and a carbohydrate component are well known. They are intended to be reconstituted with a liquid, usually before consumption. Powdered nutritional compositions include infant formulas, growing-up milks and compositions for clinical nutrition, such as compositions for enteral feeding. Typically, such products are prepared by mixing all ingredients with water; heat treating the liquid mixture to reduce the bacterial load; homogenizing the mixture; and then spray drying it.

[0003] Extrusion is a very efficient method, which significantly reduces the amount of required water and energy to a minimum, and generally produces an extrudate that can be dried and ground into a powdery substance. To date, the use of extrusion to produce powdered infant formulas is very limited, see for example WO 2006 / 094995, WO 2011 / 15965653, WO 2014 / 066680, WO 2014 / 164956 and US 2008 / 241337. The inventors of the present invention have developed a method based on extrusion for preparing infant formulas, which is cost-effective and produces excellent products. Summary of the invention

[0004] The inventors of the present invention have developed a method for preparing an infant formula product using extrusion. In the method of the present invention, the concentration of the aqueous stream is carefully controlled so that each necessary and preferred step is performed optimally, while the amount of water added and the amount of water that needs to be removed thereafter to obtain a dry infant formula are minimized. In addition, the method of the present invention is efficient in terms of energy consumption and water utilization. The amount of water used to dissolve components or dilute the stream is minimized and avoided as much as possible. Therefore, the energy-consuming water removal performed to obtain the final dry powder is also minimized.

[0005] In addition, the introduction of gas during step (d), combined with spray drying during step (e), provides an infant formula product with increased porosity compared to infant formula products of the prior art, both obtained by extrusion and spray drying. Such a product has improved properties, especially dissolution properties, over conventional infant formula products. Therefore, the present invention also provides an infant formula product obtainable by the method of the present invention, and the use of an infant formula product of the present invention or an infant formula product by the method of the present invention for improving the dissolution properties of an infant formula product, in particular improved wettability and foaming properties.

[0006] Another advantage of the method of the present invention is that it hardly causes damage to the existing preparation method of the infant formula product that does not use extrusion, making it easy to be converted into an existing processing plant. In terms of the hardware configuration and the machine used in the conventional method including the spray drying step, limited adaptability is required. In addition, the method of the present invention is highly versatile with respect to raw materials, and operates efficiently when using the conventional raw materials for the preparation of infant formula products. In addition, the method of the present invention can take into account the (natural) variation of raw material composition very well, because before carrying out the homogenization step, the level of related ingredients can be monitored and regulated as needed. In addition, the capital expenditure cost represented by the capital cost of every kilogram of product prepared by the method of the present invention is very advantageous.

[0007] The process of the present invention minimizes the heat load imposed on the protein component by maintaining ideally low temperatures at all stages. Thus, the resulting infant formula product better simulates the gold standard set by human milk compared to infant formula products that are subjected to higher temperatures during processing, particularly higher extrusion temperatures.

[0008] Another advantage of the method of the present invention is that both heat-treated and unheat-treated proteins can be used as raw materials, because they can enter the method at different stages. However, by contacting the proteins with a liquid stream and allowing them to enter the method, they form an essential part of the finished product by forming a protective layer around the lipid component and / or by forming a part of lipid-containing particles rather than being present as a separate particle in the infant formula product. This is particularly relevant to preventing lipid oxidation by reducing exposure to air.

[0009] Additionally, the process of the present invention enables the use of highly concentrated ingredients in a wet mixing process, thereby minimizing water usage while preventing equipment scaling.

[0010] Thus, the present invention provides a flexible, balanced and efficient extrusion-based infant formula preparation process that can use readily available ingredients, wherein as much of the desired protein as possible (but as much of the desired lipids and carbohydrates as possible) is subjected to a heat treatment step, and also provides room for adding ingredients during the extrusion step if desired. This flexibility is an advantage considering that infant product manufacturers should produce different formulas to suit demanding markets and use as simple and basic a processing line as possible to supply all the products sold.

[0011] The infant formula product obtained by the process of the present invention shows the desired reconstitution (dissolution) behavior without undesired caking or sticking. The process of the present invention provides a nutritional composition which disperses easily when mixed with a liquid (usually water) to give a homogenous liquid mixture of protein, fat and carbohydrates without visible separation of aqueous and non-aqueous phases.

[0012] Furthermore, the desired low levels of free fat in infant formula products are achieved by the process of the present invention. DETAILED DESCRIPTION

[0013] The method of the present invention is used to prepare an infant formula product and comprises the following steps:

[0014] (a) subjecting an aqueous mixture having a protein component and a carbohydrate component to a heat treatment step,

[0015] (b) mixing the aqueous mixture with a lipid component,

[0016] (c) subjecting the aqueous mixture comprising the lipid component, the carbohydrate component and the heat-treated protein component to a homogenization and emulsification step to obtain a homogenized oil-in-water emulsion having a total solid content of 45-80% by weight;

[0017] (d) conveying the homogenized emulsion into an extruder, independently adding a digestible carbohydrate (e.g. lactose) and optionally dietary fiber into the extruder, and extruding the contents of the extruder to obtain an extruded aerated material, wherein gas is injected into the extruder;

[0018] (e) preparing an infant formula product from the extruded aerated material.

[0019] In one embodiment, the mixing in step (b) is carried out directly after the heat treatment of step (a), which means that this occurs when the heat-treated aqueous mixture does not substantially change. In one embodiment, the step of increasing the total solid content of the aqueous mixture is carried out directly after the heat treatment of step (a), which means that this occurs when the heat-treated aqueous mixture does not substantially change. In one embodiment, the mixing in step (b) is carried out directly after the step of increasing the total solid content of the aqueous mixture, which means that this occurs when the aqueous mixture containing the total solid content increased does not substantially change. In one embodiment, the homogenization and emulsification in step (c) are carried out directly after the mixing of step (b), which means that this occurs when the aqueous mixture does not substantially change. In one embodiment, the extrusion in step (d) is carried out directly after the homogenization of step (c), which means that this occurs when the homogenized emulsion does not substantially change. In one embodiment, the preparation of step (e) is carried out directly after the extrusion of step (d), without substantially changing the extruded material.

[0020] In one embodiment of the process of the present invention, step (e) comprises a spray drying step.

[0021] In one embodiment, the temperature of the process of the invention does not exceed 75°C, preferably does not exceed 70°C, except for the heat treatment of step (a) and possibly, if present, the spray drying as part of step (e). The nutrients ultimately present in the infant formula product are preferably not unnecessarily exposed to an undesirably high heat load. In addition to the heat treatment step, the temperature in the spray drying step, if part of step (e), may also exceed 75°C. Due to the gas injection in step (d), the residence time in the spray dryer can be reduced, thereby reducing the heat load exposed to the final product. In addition, it has been found that spray drying has a limited impact on the nativeness of the protein.

[0022] Preferably, the infant formula product is an infant formula, a follow-on formula, a toddler milk or a growing-up milk.

[0023] In the context of the present invention, an aqueous mixture is produced in many stages and is used again in subsequent stages. Such an aqueous mixture is a mixture based on water as a liquid, in which other components can be dissolved or dispersed. In the method of the present invention, the aqueous mixture undergoes several treatments, but all of these times remains an aqueous mixture until the extrusion step is performed, in which the mixture is converted into a dry extrudate. The aqueous mixture may also be referred to as an "aqueous stream" or just a "stream". Throughout the method, the concentration of the aqueous mixture may be defined by its total solids content. It is expressed as % by weight, based on the total weight of the stream. "Solids", "total solids" or "total solids content" refers to all components in the aqueous stream except water, even if these solids are liquid at ambient conditions, such as oil.

[0024] Raw materials and heat treatment step (a)

[0025] One of the steps in the process of the present invention is step (a) wherein the aqueous mixture having a protein component and a carbohydrate component is subjected to a heat treatment step.

[0026] The aqueous mixture with the protein and carbohydrate components is preferably composed of a conventional and widely available raw material or source containing any suitable protein level, preferably micronutrients, which can be selected from skimmed milk, whey protein concentrate (WPC), whey protein isolate (WPI), milk protein isolate (MPI), milk protein concentrate (MPC), demineralized whey protein powder, skimmed milk concentrate. Since the inclusion of a heat treatment step in the method of the present invention provides a first flexibility in the selection of raw materials containing protein, the raw material containing the protein component is preferably not heat treated. Typically, the protein source used to provide the protein component is therefore not pure or high grade, but contains lactose, because lactose is present as a component in these milk protein sources. Therefore, in a preferred embodiment, the raw material used in step (a) does not include a lactose source that does not contain a large amount of milk protein. In other words, the raw materials of step (a) do not include lactose having a purity of greater than 92 wt%, preferably greater than 90 wt%, more preferably greater than 85 wt%, based on dry weight, because such lactose sources, such as refined lactose, are of high food grade and are preferably added as such during the extrusion step (d) in the process of the present invention. If maltodextrin needs to be added, it is also most preferably not added in step (a), but added downstream, such as in the extrusion step (d) or in a dry blending step after extrusion, so that the protein level based on dry weight during heat treatment is as high as possible.

[0027] In a preferred embodiment, the carbohydrate component added in step (a) comprises or consists of digestible carbohydrates naturally present in cow's milk, preferably monosaccharides and / or disaccharides. More preferably, the carbohydrate component comprises lactose, as this is a very preferred component of infant formula and naturally present in cow's milk.

[0028] In a preferred embodiment, the amount of lactose contained in the carbohydrate component of step (a) accounts for 15 to 75% by weight of the total lactose content of the infant formula product prepared by the method of the present invention, based on dry weight. More preferably, the amount of lactose in step (a) accounts for 20 to 70% by weight or 22 to 65% by weight of the total lactose content of the infant formula product prepared by the method of the present invention, based on dry weight. Any remaining lactose to be included in the infant formula product is preferably added in steps (d) and / or (e), most preferably at least 20, 40 or 50% by weight of the remaining lactose to be added is added by step (d).

[0029] In a preferred embodiment, the weight ratio of protein to carbohydrate in the aqueous mixture is from 1.0 to 0.01, more preferably from 0.5 to 0.05, most preferably from 0.2 to 0.1. The weight ratio of protein to carbohydrate in the aqueous mixture is based on the purpose of preparing an infant formula and takes into account that lactose may be added further downstream in the process, i.e. during the extrusion step (d) and / or added to the extruded material in step (e).

[0030] Typically, a whey protein source (preferably skim milk, WPC and / or WPI) and a casein source (preferably a milk protein source, more preferably MPI and / or MPC) are mixed to obtain a protein mixture. The mixing ratio of the whey protein source and the milk protein source depends on the desired product to be prepared, and typically the ratio of whey protein to casein is 9 / 1 to 1 / 9, preferably 5 / 1 to 1 / 5, more preferably 3 / 1 to 1 / 1, and most preferably about 6 / 4. Alternatively, the whey protein source and the milk protein source are mixed in a ratio of 1 / 9-1 / 9, more preferably 1 / 2-2 / 1, and most preferably about 1 / 1, based on the weight of the protein fraction in each source.

[0031] In a preferred embodiment, the amount of protein contained in step (a) is 70 to 100% by weight of the total protein present in the infant formula obtained by the present invention, based on dry weight. Preferably, the amount of protein is between 80 and 100% by weight, more preferably between 90 or 95 and 100% by weight. Adding such a large amount of protein in step a) ensures a uniform and good emulsification of protein and oil in the oil-in-water emulsion further downstream in the process, as well as the entrapment of oil by protein.

[0032] Typically, water-soluble micronutrients such as vitamins and minerals conventional in the art of infant formula preparation are added to the aqueous mixture of step (a). Although one or more of the ingredients may be in dry form, it is preferred that they are in liquid form, preferably in concentrated form. Thus, due to the inclusion of these vitamins and minerals in the form of concentrates or dry powders, only limited unnecessary water removal is required. The advantage of including these micronutrients in step a) is that they are fully integrated into the powder particles constituting the obtained product.

[0033] The raw materials are preferably used in liquid form or dissolved in a batch process to provide an aqueous mixture so as to control the uniformity and concentration of the ingredients of the prepared product.

[0034] In step (a), the aqueous mixture with protein component and carbohydrate component is subjected to heat treatment step. Preferably, before heat treatment, the aqueous mixture is completely dissolved and has uniform concentration. Preferably, if the raw material provided (such as skim milk and / or whey protein concentrate) is used for infant formula preparation in dry form, the aqueous mixture is obtained by dissolving in batches. The method of the present invention is very suitable for large-scale preparation. Therefore, in one embodiment, the aqueous mixture is fed to the heat treatment of step (a) with a flow rate of 500-25000kg / h, preferably 1000-10000kg / h, most preferably 2500-6000kg / h.

[0035] In step (a), the aqueous mixture comprising the protein component and the carbohydrate component is subjected to a heat treatment, which is designed to obtain a microbiologically safe protein component and an infant formula product with a good shelf life. Any suitable type of heat treatment known in the art can be used, such as pasteurization or sterilization, such as HTST, ESL, UHT, dry heat or moist heat sterilization. The purpose of the heat treatment referred to herein is to reduce the microbial load to such an extent that the resulting infant formula product is free of microorganisms and is safely consumed by infants. In particular, it is safe for Bacillus cereus and Enterobacter sakazakii, such as specified in European Regulation No. 2073 / 2005 (Amendment No. 1441 / 2007) in 2007.

[0036] Advantageously, unlike dry-mixing-based methods in which the aqueous stream does not need to be heat-treated, the aqueous mixture comprising the protein component is heat-treated as a major part of the inventive method. Therefore, the protein component introduced can therefore have a more variable grade or quality. An advantage of carrying out this integrated heat treatment step on an industrial scale is that microbial safety can be better controlled and directed and recontamination of the provided protein component is prevented. It should be noted that spray drying is generally not considered as a microbicidal step in this article.

[0037] The heat treatment is preferably carried out on an aqueous mixture having a total solids content of 15-40 wt. %, preferably 20-35 wt. %, more preferably 18-32 wt. %, and most preferably about 25-32 wt. %. At such concentrations, the heat treatment is performed optimally, since the aqueous mixture is further processed optimally during and after the heat treatment step, and is carried out in the mixing tank used to obtain the aqueous mixture before the aqueous mixture can be subjected to the heat treatment. The total solids content of the mixture in step (a) is the result of a balance between preventing scaling of equipment (e.g., mixing tanks, piping, etc.) when the total solids content is too high and preventing unnecessary removal of excess water in steps downstream of the heat treatment.

[0038] The aqueous mixture in step (a) is subjected to heat treatment before being mixed with the lipid component in step (b), enabling working at optimally high total solids levels and protein levels, which means operating under high viscosity conditions. In addition, excluding the lipid component from the heat treatment in step (a) means that the process of the present invention consumes less energy.

[0039] Preferably, the lipid component is not actively added as a pure single ingredient in step (a). Lipid may be present in small amounts in the aqueous mixture undergoing step (a), as it may be present in the sources for the protein component and the carbohydrate component. The method is fully operable when lipid is present from step (a).

[0040] Optional concentration step of the heat-treated aqueous mixture

[0041] After heat treatment, but preferably before adding lipid components, the aqueous mixture can be concentrated. Concentration can be completed by any means known in the art, such as (partial) evaporation or filtration. In one embodiment, the aqueous mixture obtained in step (a) is preferably subjected to partial evaporation of water under reduced pressure and at a relatively low temperature. Preferably, it is concentrated so that before adding the lipid blend, the concentrated aqueous mixture is 35-60% by weight total solids, preferably 35-55% by weight total solids, more preferably 40-55% by weight total solids, more preferably 40-51% by weight total solids, most preferably 45-51% by weight total solids. The inventors of the present invention have found that after adding lipids, this concentration provides the optimal concentration before homogenization and extrusion steps. If concentration occurs after adding the lipid blend, the final concentration may be slightly higher, with a composition of 45-80% by weight total solids, preferably 45-73% by weight total solids, more preferably 53-68% by weight total solids, most preferably 60-65% by weight total solids still fed to the extruder.

[0042] Therefore, in a preferred embodiment, before mixing with the lipid component, the total solid content of the aqueous mixture obtained in step (a) is increased, preferably by an evaporation step. In one embodiment, in the concentration step, the amount of water preferably removed in the evaporator is 200-10000 kg / h, preferably 800-5000 kg / h, most preferably 1500-2500 kg / h.

[0043] Mixing of fat components in step (b)

[0044] In mixing step (b), the aqueous mixture obtained in step (a) is mixed with the lipid component. Mixing can be carried out in any suitable manner, preferably including an online injection system. In one embodiment, the aqueous mixture is fed to step (b) with a flow rate of 300-20000kg / h, preferably 800-10000kg / h, most preferably 1500-5000kg / h. The lipid component added in step (b) is preferably fed to step (b) with a similar flow rate, therefore 300-20000kg / h, preferably 800-10000kg / h, most preferably 1500-5000kg / h. In the context of the present invention, although the temperature for carrying out step (b) is not critical, the temperature of preferred step (b) is 30-75°C, more preferably 50-70°C, most preferably 55-65°C.

[0045] The lipid component is added before homogenization and emulsification. As known in the art, the lipid component generally contains necessary and preferred lipids for the preparation of infant formula. Preferably, it also contains fat-soluble vitamins. Although the lipid component can be added at any point before homogenization, it is added after the heat treatment step. This is because adding the lipid component will increase the total solid content of the mixture, which is undesirable before the heat treatment step. Like this, most of the space for the available solid content in the heat-treated mixture in step (a) is occupied by the protein component, thereby avoiding the unnecessary inclusion of the lipid component at this method stage.

[0046] Mixing the lipid components in step (b) results in an increase in the total solids content of 5 to 25 wt%, preferably 9 to 20 wt%, more preferably 12 to 18 wt%.

[0047] After mixing the lipid components in step (b), a composition having a total solid content of 45-80 wt %. Preferably, after mixing the lipid components, the composition has a total solid content of 45-73 wt %, preferably 53-73 wt % total solids, such as 60-73 wt %, more preferably 53-68 wt %, preferably 60-65 wt %.

[0048] Preferably, the lipid component admixed in step (b) comprises fat-soluble vitamins.

[0049] Step (c) homogenization and emulsification to obtain an oil-in-water emulsion

[0050] In step (c), the aqueous mixture comprising the lipid component, the carbohydrate component and the heat-treated protein component is homogenized and emulsified to obtain a homogenized oil-in-water emulsion having a total solid content of 45-80% by weight, preferably 45-73% by weight total solids, more preferably 53-73% by weight, such as 60-73% by weight, more preferably 53-68% by weight total solids, and most preferably 60-65% by weight total solids. This concentration is particularly desirable for the subsequent extrusion step, wherein due to the limitations of the equipment used to process the oil-in-water emulsion, the solid content should not exceed the specified upper limit and should not be less than the lower limit, because too much water will have to be removed downstream. In one embodiment, the aqueous mixture is fed to step (c) at a flow rate of 800-40000 kg / h, preferably 2000-20000 kg / h, and most preferably 3000-7500 kg / h.

[0051] The aqueous mixture subjected to step (c) preferably contains substantially all the lipids of the final product. The aqueous mixture typically contains carbohydrates such as lactose derived from a whey protein source and / or a milk protein source, but the inventors have found that additional lactose may be added as required during extrusion in step (d).

[0052] The introduced aqueous mixture contains both casein and whey protein, preferably in the ratio required for the final product, preferably a ratio of whey protein to casein of 9 / 1 to 1 / 9, preferably 5 / 1 to 1 / 5, more preferably 3 / 1 to 1 / 1, most preferably about 6 / 4. The presence of both whey protein and casein before homogenization has been found to be advantageous, since after homogenization, preferably before extrusion, the proteins are uniformly distributed in the emulsion as such and ultimately in the infant formula product obtained.

[0053] An advantage of obtaining a uniform oil-in-water emulsion before starting to squeeze out is that uniformly distributed nutrients are obtained throughout the composition, which is easier to achieve than relying on the extrusion step to homogenize and emulsify. In addition, this sequence of steps ensures that the emulsion thus obtained contains lipids protected by a protein layer. This protection is important because dry infant products require consistent components and long-term stability. Importantly, before squeezing out, the free fat (or unencapsulated fat) present is reduced to a minimum and does not change during squeezing out. Therefore, in the early upstream stages of the method, the ingredients of the infant formula have been protected from deterioration (rancid) and oxidation after unnecessary air exposure.

[0054] Homogenization of an aqueous mixture containing a protein component, a lipid component and a carbohydrate component is known in the art, and the exact conditions under which the homogenization is performed are also known to the skilled person.

[0055] Preferably, homogenization is carried out at a temperature of 50 to 80° C., preferably 54 to 76° C., more preferably 60 to 70° C., and preferably within 5 seconds, more preferably less than 3 seconds. The specified range ensures that protein denaturation and degradation of thermolabile components are minimized, but is high enough to still be able to properly carry out step (c) on a product with good viscosity.

[0056] In a preferred embodiment, the total solids content obtained during steps (a) and (b) is 15-40% by weight, preferably 20-35% by weight, most preferably about 25-32% by weight after step (a); and 45-80% by weight, preferably 45-73% by weight total solids, more preferably 53-68% by weight, or more preferably 60-65% by weight after step (b), wherein the increase in total solids in step (b) is due to the addition of lipid and the optional inclusion of a concentration step prior to the addition of lipid. It is important that the homogenized oil-in-water emulsion is fed to the extruder with a total solids content of 45–80% by weight.

[0057] In one embodiment, the viscosity of the oil-in-water emulsion is from 10 to 2000 mPa.s, preferably from 10 to 1500 mPa.s, more preferably from 50 to 1200 mPa.s, more preferably from 100 to 1000 mPa.s, most preferably from 200 to 700 mPa.s.

[0058] The viscosity referred to herein is measured at 70°C at a shear rate of 1 / 1000s as this temperature is representative of the conditions in an extruder, allowing the skilled person to simulate these conditions on a laboratory scale to quickly assess the performance of a particular infant formula under investigation.

[0059] Viscosity can be measured using any suitable instrument. For the avoidance of doubt, the Anton The viscosity is measured by Physica MCR301 (with cone-plate probe (cone angle 1°), probe number CP50 1 4310) so that the measurement is carried out under the specified conditions. In brief, the viscosity measurement follows a first step procedure, where the shear rate is increased from 1 s -1 Increase to 1000s -1 , followed by a peak hold step at 70 °C for 1000 s -1 The viscosity was measured five times at a shear rate of 1.5 Å and the average value was obtained using the specified instrument.

[0060] Step (d) Extruding the oil-in-water emulsion

[0061] The homogenized oil-in-water emulsion is conveyed or transported to an extruder, and separately from the emulsion, digestible carbohydrates (eg lactose) and optionally dietary fibers are added to the extruder, and the contents of the extruder are extruded to obtain an extruded material.

[0062] In this context, the separate addition of digestible carbohydrates is defined as being added to the extruder through an inlet not used for feeding the oil-in-water emulsion into the extruder. In this context, the separate addition of dietary fiber is defined as being added to the extruder through an inlet not used for feeding the oil-in-water emulsion into the extruder. Although digestible carbohydrates and carbohydrates can be added together through a single inlet of the extruder, they are preferably added through separate inlets.

[0063] Extrusion is well known in the art and any means known to the skilled person may be used. Preferably, extrusion is carried out at a temperature below 75°C, more preferably below 70°C, such as 50-75°C, more preferably 60-70°C, and most preferably 62-68°C. Above these temperatures, proteins may undergo unwanted denaturation, which is undesirable for infant formula. The inventors have found that the specified temperature range does not affect the properties of the final product.

[0064] Typically, the oil-in-water emulsion enters the extruder on one side of the extruder. Inside the extruder, the movement of the screw makes it move forward. The residence time in the extruder is preferably 30 seconds to 3 minutes, for example 50 seconds to 2 minutes. But preferably, compared with the existing extrusion step used in the preparation of the infant formula formula, the time is shortened because the stream introduced is more homogenized and more complete in terms of the required final nutrient composition. Therefore, a preferred residence time is less than 50 seconds, for example 20 to 50 seconds. In one embodiment, the extruder is operated at a flow rate of 2000-60000kg / h, preferably 5000-30000kg / h, most preferably 7500-15000kg / h.

[0065] The pressure exerted on the composition during extrusion is preferably from 20 kPa to 10 MPa.

[0066] The total solids content of the oil-in-water emulsion fed into the extruder is 45-80 wt% total solids, preferably 45-73 wt% total solids, more preferably 53-73 wt%, such as 60-73 wt%, more preferably 53-68 wt% total solids, most preferably 60-65 wt% total solids. The inventors of the present invention have found that this concentration provides the best results both in terms of final product properties as well as process efficiency. It is noteworthy that the amount of water that needs to be added to the aqueous mixture prior to the extrusion step is kept to a minimum, while extrusion is still performed in an optimal manner.

[0067] The inventors of the present invention have found that some solid materials that are usually incorporated into the nutritional composition of the present invention can be advantageously added during the extrusion process. In the infant formula preparation process, ingredients such as lactose and dietary fiber are usually added in solid form. In addition, from a preparation perspective, it is not important to have all lactose and dietary fiber during the homogenization step (c) to obtain the final infant formula product. Therefore, lactose and optional dietary fiber are added during the extrusion process.

[0068] In one embodiment, the amount of lactose added in step (d) is 0 to 70 wt %, preferably 2 to 70 wt % (based on dry weight) of the total amount of lactose contained in the infant formula obtained in step (e). Preferably, the amount is 0 to 50 wt % or 25 to 50 wt %.

[0069] In an alternative embodiment, the amount of lactose added in step (d) is 0 to 40 wt %, preferably 2 to 40 wt % of the total dry weight of the infant formula obtained in step (e). More preferably, the amount is 0 to 30 wt %, most preferably 2 to 30 wt %.

[0070] The digestible carbohydrates added in step (d) preferably comprise or consist of lactose and / or maltodextrin.

[0071] In a preferred embodiment, the digestible carbohydrates (e.g. lactose and / or maltodextrin) fed into the extruder are of (infant) food grade quality and have a purity of greater than 90% by weight, preferably greater than 95%. Purity herein refers to the presence of the intended ingredients expressed as dry weight, so water as an impurity is explicitly excluded. Since lactose and / or maltodextrin are added in dry form, large amounts of water are prevented from entering the preparation process, so there is no need to remove the water again afterwards. Therefore, the management of liquid streams becomes more efficient. Adding these ingredients during the extrusion process reduces the need for water addition and allows for higher total protein solids to be present upstream of the extrusion step.

[0072] The addition point of lactose and / or maltodextrin in the extruder is preferably before the addition of dietary fiber to aid in the dissolution of the digestible carbohydrates. Dietary fibers, such as galacto-oligosaccharides, can be added later in the extrusion process, as these fibers can be added as concentrated liquids.

[0073] In one embodiment, some of the protein required for preparing the infant formula is added during the extrusion process. The method of the present invention allows such flexibility because all lipids are fully emulsified with the protein in step (c). Preferably, 0 to 30% by weight of the total protein component of the infant formula product is added in step (d), more preferably 0 to 20 or most preferably 0 to 10% by weight of the total protein.

[0074] In a preferred embodiment, dry lactose powder and / or dry maltodextrin powder is added during the extrusion process.

[0075] In a preferred embodiment, dietary fiber is added in the form of a concentrated liquid or syrup, such as galacto-oligosaccharide.

[0076] In a preferred embodiment, the amount of digestible carbohydrates, mainly lactose and / or maltodextrin and optionally dietary fiber added is such that the total solids content of the material leaving the extruder is 75-90% by weight, preferably 75-88% by weight, more preferably 80-88% by weight, most preferably 83-87% by weight.

[0077] During the extrusion process, gas is injected into the extruder. The gas injection occurs downstream of the two inlets for adding emulsions, carbohydrates and optional dietary fiber and any other substances that can be added to the extruder. In the extrusion step (d), the oil-in-water emulsion is mixed with gas to obtain a uniform aerated structure. Injecting gas during the step of stirring the emulsion ultimately produces an extrudate with an aerated structure. In the context of the present invention, "aeration" refers to a solid or liquid matrix containing bubbles of trapped gas. This gas injection is conducive to obtaining the functional and use characteristics of powdered milk, such as density, porosity, wettability, and complete and instantaneous rehydration capacity. In addition, the aerated structure of the extrudate promotes its subsequent drying by significantly increasing the exchange surface area between the extruded emulsion and the ambient medium, and thereby promoting the transfer of steam. In addition, the aerated extrudate has a lower viscosity and better fluidity than the non-aerated extrudate, which is conducive to further processing, such as drying. The inventors of the present invention have found that aeration increases the fluidity of the extrudate and prevents a pasty structure that is impossible to feed into a spray dryer. As a part of step (e), this pasty extrudate should be converted into powder by air-drying thin layer extrudate (hardening) and grinding dried material. This drying step provides a powder with poorer recovery and dissolution characteristics than spray-dried powder. On the contrary, the aeration of the present invention ensures sufficient fluidity and sufficiently low viscosity so that the extrudate can be fed to the spray dryer to convert the extrudate into powder. In addition, it is found that the aeration of the powder reduces the foaming after the powder is recovered. In the case of infant formula products, foaming is undesirable because the foam sticks to the bottle to a great extent and therefore stays in the bottle during feeding, thereby potentially leaving important nutrients in the bottle. Therefore, from the perspective of user experience, less foam directly after recovery is preferred. In addition, it is preferred that the foam disappears faster so that more nutrients are absorbed by the liquid before the feeding event ends. As shown in the examples, compared with conventional infant formula products, infant formula products of the present invention produce less foam when recovered.

[0078] Such inflation during extrusion can be carried out in an extruder-aerator known in the art, such as an intermeshing twin-screw extruder-aerator. Any suitable gas can be used to inject into the extruder, preferably an inert gas such as nitrogen (N2) or carbon dioxide (CO2), most preferably N2. The use of N2 provides particularly advantageous solubility characteristics. Preferably, 0.3-4.0 L, more preferably 0.5-2.0 L, most preferably 0.8-1.0 L of gas (under ambient conditions) is injected per kg of the total weight of the extruded emulsion, wherein the total weight refers to the total weight of the emulsion, digestible carbohydrates and any other material that can be added separately to the extruder upstream of the gas injection.

[0079] For further guidance on how to perform gas injection, the skilled person may refer to US 8268378 or Bouvier et al. Dairy Sci & Technol. 2013, 93, 387-399, which are incorporated herein by reference.

[0080] Extruded material can also be referred to as extruded aerated material or simply extrudate. The extrudate has a porous structure, usually in the form of foam. The extrudate contains holes or voids of various sizes, in which the gas injected into the extruder is trapped. The extruded material preferably contains substantially all the proteins and / or lipids required for the infant formula nutritionally. In other words, it is not necessary to add lipid and / or protein to the extruded material. Therefore, it is not necessary to dry mix with other protein components such as skim milk, thereby avoiding the end product having an undesirable wide or uneven particle size distribution due to the addition of a product similar to skim milk. In this way, a desirable uniform particle density distribution is obtained. In addition, due to the presence of minerals in this natural product, adding a milk protein source or a cow's milk protein source in the downstream portion of this method can interfere with the mineral composition.

[0081] In the context of the present invention, dietary fiber is synonymous with non-digestible oligosaccharides and polysaccharides, most preferably galacto-oligosaccharides, fructo-oligosaccharides, polyfructose and mixtures thereof.

[0082] Step (e) preparing infant formula from the extruded material

[0083] The extrusion step provides an extrusion material comprising substantially all of the solids that have been charged to the extruder, including the solids of the oil-in-water emulsion and any solids that are additionally charged during the extrusion process. The extrusion material may also be referred to as an extrusion mixture or extrudate, and is typically in the form of small pellets.

[0084] In a preferred embodiment, the extruded material is nutritionally complete when leaving the extruder and meets the requirements of infant formula nutritionally. In this case, the preparation of step (e) includes conventional steps, such as drying, grinding and / or packaging, so that the extruded material is prepared to be sold as an infant formula product. In this case, no further nutritional adaptation is required and is not included in step (e).

[0085] Alternatively, the preparation in step (e) also includes some nutritional supplementation of the extruded material to obtain a nutritionally complete infant formula product. Preferably, the nutritional supplementation includes a dry blend of the missing nutrients or the missing amount of nutrients. Alternatively, any required supplementation is performed at an early stage of the method, for example before step (a), during the mixing period of step (b) and / or during the extrusion period of step (d), so that no further supplementation is required during step (e).

[0086] In one embodiment, such supplementation includes the addition of lactose and / or minerals and / or vitamins as may be required to provide a nutritionally complete formula.

[0087] In a preferred embodiment, digestible carbohydrates (preferably lactose, but also maltodextrin) and / or micronutrients are added to the extruded material to provide an infant formula. Lactose and / or maltodextrin are added to the infant formula product to provide an infant formula and can be advantageously completed using a source of distribution with a fully overlapping particle size distribution or a distribution falling within the distribution of the extruded material, so that the unbalanced distribution that adversely affects the properties and behavior of the powder particles (e.g., fluidity) is not caused, which may be caused by adding a milk protein source at this stage of the method. The particle size distribution of commercially available lactose or maltodextrin is easily controlled by the supplier as required, and can be easily determined by a technician. The amount of lactose and / or maltodextrin added to the extruded material is 0 to 40% by weight based on the dry weight of the final infant formula obtained, preferably 0 to 30% by weight. Alternatively, the amount of lactose added to the extruded material is 0 to 70% by weight based on the total amount of lactose in the final infant formula obtained, more preferably 0 to 50% by weight. For maltodextrin, a more preferred amount added to the extrusion material is 1 to 20 wt%, preferably 1 to 15 wt%, based on the dry weight of the final infant formula obtained.

[0088] The total solids content of the extruded material is typically 75-90 wt%, preferably 75-88 wt%, more preferably 80-88 wt%, most preferably 83-87 wt%.

[0089] In a preferred embodiment, as part of step (e), the extruded material is subjected to a drying step to further reduce the moisture content. This drying can be carried out by any means known in the art, such as flash drying, vacuum drying, belt drying, microwave drying, infrared drying and spray drying. This drying step can be carried out at a flow rate of 2000-40000 kg / h, preferably 4000-20000 kg / h, and most preferably 6000-12000 kg / h. The final moisture content after drying is preferably 0.5-5% by weight, preferably 1-4% by weight, more preferably 2-3.5% by weight, and most preferably 2.5-3% by weight, based on the total weight of the product. This low moisture content allows the infant formula product to have a longer shelf life, for example at least 12 months.

[0090] In a preferred embodiment, step (e) includes a spray drying step. It was found that spray drying further increased the porosity of the powder particles, thereby increasing their solubility. Spray drying can be carried out by any means known in the art. Typically, the spray dryer is carried out at an inlet temperature of 170-220°C and an outlet temperature of 40-90°C. In a preferred embodiment, the outlet temperature is 45-85°C. The residence time of the spray dryer can be as low as 10-20s, because the porous structure of the extrudate allows faster moisture transfer, thereby faster drying. In addition, the outlet temperature can be reduced compared to conventional spray dryers that are usually operated at 55-95°C.

[0091] During the spray drying process, the gas trapped within the bubbles of the extrudate expands, thereby forming hollow particles. Due to the presence of many small bubbles in the extrudate, highly porous particles are formed during the spray drying process.

[0092] The above-mentioned other types of drying are also feasible. Due to the gas injection in step (d), the porosity of the obtained product will still increase, but the additional increase in porosity achieved by the spray dryer is not achieved. Nevertheless, such products are suitable as infant formula products.

[0093] In a preferred embodiment, as part of step (e), the extruded material, preferably the dried extruded material, is ground. Preferably, grinding is performed to obtain a free-flowing powder. Grinding is particularly preferred if the drying step is not performed by spray drying but, for example, using a belt dryer or a flash dryer. When spray drying is used, the grinding step can advantageously be omitted.

[0094] Hence, the product of the process according to the invention is an infant formula product and is preferably nutritionally complete when it leaves the extruder.Preferably, the infant formula product is an infant formula, a follow-on formula, a toddler milk or a growing-up milk.

[0095] A nutritionally complete formula or infant formula product is a dry powder that requires only reconstitution in a specified amount of water to give a ready-to-feed product suitable for feeding from a baby bottle.

[0096] Infant formula product of the present invention is in powder form, and is intended to be reconstituted with liquid (usually water) to obtain an infant formula product that can be used to provide nutrition to an infant. Powder is advantageously a free-flowing powder so that it can be easily scooped out and measured. Product of the present invention is easily dissolved in water at ambient temperature to prepare the ready-to-eat product for immediate consumption. Ready-to-eat products are stable within the time required for infant consumption, and particularly they contain stable emulsions. In addition, based on total lipid content, it is desirable that the free fat present is lower, usually less than 2 % by weight or even less than 1.5 % by weight or less than 1 % by weight. Since free fat is easily oxidized during storage, its content is preferably as low as possible. It should be noted that the free fat content observed after the homogenization step is expected to remain very low after extrusion and other steps of the method of the present invention. These low free fat contents depend on the final product.

[0097] Preferably, the product obtained by the process of the present invention is an infant formula. Infant formula herein is defined as a nutritionally complete formula and includes infant formula (meaning for infants aged 0 to 6 months), follow-on formula (meaning for infants aged 6 to 12 months) and toddler milk or growing-up milk (meaning for toddlers or children aged 1 to 3 years).

[0098] The infant formula of the present invention comprises or preferably consists of the essential macronutrients and micronutrients specified by law. Such requirements are usually specified by regulatory agencies, such as EU Directives 91 / 321 / EEC and 2006 / 141 / EC or US Food and Drug Administration 21 CFR Ch 1 Part 107.

[0099] Infant formula products directly obtained or obtainable by the method of the present invention or infant formula obtained or obtainable by the method of the present invention are also part of the present invention. The typical feature of the infant formula product of the present invention is the increased porosity compared to the milk-based powders of the prior art. Typically, the porosity is 30-75%, preferably 45-70%, most preferably 55-65%. The porosity of conventional spray-dried milk-based powders can be as low as 20–25%. In this article, porosity is defined as the percentage of pore volume to the total volume of the powder. Porosity can be determined by scanning electron microscopy, for example as defined in US 5596815.

[0100] Taking into account the increased porosity compared to the prior art milk powder, the infant formula product of the present invention exhibits excellent solubility. Additionally or alternatively, the infant formula product of the present invention may be made of 150-650 kg / m 3 , preferably 200-400kg / m 3 , more preferably 250-350kg / m 3 The bulk density is limited.

[0101] Thus, the process of the present invention provides an extruded infant formula product having improved solubility compared to conventional extruded infant formulas as well as conventional spray dried formulas.Thus, the advantages associated with the process of the present invention are combined with the preparation of a product having superior properties.

[0102] Modular system for carrying out the preparation method of the present invention

[0103] Another aspect of the invention relates to a modular system for carrying out the method steps for preparing an infant formula according to the appended claims.

[0104] In another aspect, the present invention relates to a modular system for preparing an infant formula, comprising:

[0105] - a thermal treatment module for thermally treating an aqueous mixture having a protein component and a carbohydrate component,

[0106] - a mixing module for mixing the aqueous mixture with the lipid component,

[0107] - a homogenization and emulsification module for homogenizing and emulsifying an aqueous mixture comprising a lipid component, a carbohydrate component and a heat-treated protein component to obtain a homogenized oil-in-water emulsion,

[0108] an extrusion module comprising an inlet for receiving a homogenized oil-in-water emulsion, a separate inlet for adding digestible carbohydrates and optionally dietary fibers to the extrusion module and an outlet for discharging the extruded material, and a gas injection inlet,

[0109] - Drying module, used to dry the extruded material,

[0110] - and optionally a module for grinding and / or packaging the material obtained.

[0111] In a preferred embodiment, the aqueous mixture comprising the protein component and the carbohydrate component is subjected to a heat treatment step using a module designed to obtain a microbiologically safe protein component and an infant formula product with a good shelf life. Any suitable type of heat treatment module known in the art may be used, such as pasteurization, such as HTST, ESL or UHT, or sterilization, such as dry heat or moist heat sterilization.

[0112] In a preferred embodiment, the modular system includes a module for the aqueous mixture obtained after the concentration step (a). This concentration can be completed by any means known in the art, for example, using (partial) evaporation or filtering modules. In one embodiment, the aqueous mixture obtained in step (a) preferably uses a suitable module to carry out the partial evaporation of water under reduced pressure and relatively low temperature. Preferably, the concentration module is configured to or is suitable for concentrating the aqueous mixture before adding the lipid mixture, to reach a concentration of 35-60% by weight total solids, preferably 40-55% by weight total solids, most preferably 45-51% by weight total solids.

[0113] Therefore, in a preferred embodiment, the total solid content of the aqueous mixture obtained in step (a) is preferably increased using an evaporation module, which is included before the mixing module for mixing in the lipid component.

[0114] The modular system comprises a mixing module for performing a mixing step (b), wherein the aqueous mixture obtained in step (a) is mixed with the lipid component. The mixing can be performed in any suitable manner, preferably comprising a module for an online injection system. Preferably, the mixing module comprises a device for heating the aqueous mixture obtained in step (a), the lipid component or a mixture thereof, preferably at a temperature of 30-75°C, more preferably 50-70°C, most preferably 55-65°C.

[0115] Prior to the homogenization and emulsification modules, a mixing module is included for mixing in the lipid component. Although the lipid component can be added at any point prior to homogenization, it is included after or downstream of the heat treatment module.

[0116] The modular system of the present invention comprises a homogenization and emulsification module for carrying out step (c). It is capable of obtaining a homogenized oil-in-water emulsion having a total solids content of 45-80 wt %, preferably 45-73 wt % total solids, more preferably 53-68 wt % total solids, and most preferably 60-65 wt % total solids.

[0117] The homogenization and emulsification module is configured to operate at a temperature of 50 to 80° C., preferably 54 to 76° C., more preferably 60 to 70° C., and preferably obtains a homogenized emulsion within 5 seconds, more preferably less than 3 seconds. In addition, the homogenization and emulsification module is preferably configured to operate with an oil-in-water emulsion having a viscosity of 10 to 2000 mPa.s, preferably 10 to 1500 mPa.s, more preferably 50 to 1200 mPa.s, more preferably 100 to 1000 mPa.s, and most preferably 200 to 700 mPa.s.

[0118] The homogenized oil-in-water emulsion is conveyed or transported to an extrusion module, which may also be referred to as an extruder. The module includes an inlet for receiving the emulsion, and an inlet independent of it for adding digestible carbohydrates (e.g., lactose), and optionally an inlet for adding dietary fiber. The extrusion module also includes a gas injection inlet for injecting gas into the extruder.

[0119] Suitable extrusion modules or extruders are well known in the art and known to the skilled person. Preferably, the extruder is configured to operate at an extrusion temperature below 75°C, more preferably below 70°C, such as 50-75°C, more preferably 60-70°C, most preferably 62-68°C.

[0120] Typically, the oil-in-water emulsion enters the extruder on one side of the extruder and exits as the extruded material on the opposite side so that it passes through the entire path of the extruder. Inside the extruder, the material contained therein is moved forward by the movement of the screw. The extruder is configured to operate at a residence time of preferably 30 seconds to 3 minutes, for example 50 seconds to 2 minutes. However, preferably, a shortened residence time of less than 50 seconds, for example 20 to 50 seconds, is also feasible.

[0121] Furthermore, the extruder is preferably configured to apply a pressure of 20 kPa to 10 MPa to the composition during extrusion.

[0122] The extruder is preferably configured to run with an oil-in-water emulsion having a total solids content of 45-80 wt% total solids, preferably 45-73 wt% total solids, more preferably 53-68 wt% total solids, most preferably 60-65 wt% total solids.

[0123] Any drying module for drying extruded material may be used. In a preferred embodiment, the drying module is a spray dryer.

[0124] In a preferred embodiment, the modular system further comprises a dry blending module for dry blending ingredients into the material obtained prior to packaging the infant formula.

[0125] Such a dry blending module is only required if the extruded material does not nutritionally meet the requirements of the infant formula according to the invention and needs to be supplemented with powdered ingredients, such as digestible carbohydrates, preferably lactose and / or maltodextrin.

[0126] In modular system of the present invention, independent module fluid is connected to allow material (aqueous mixture or the infant formula product in preparation) to pass into another module from one module, so that modular system can run smoothly as a whole. In one embodiment, modular system is used to prepare infant formula product of the present invention. In one embodiment, modular system is used to carry out method of the present invention.

[0127] Attached photos

[0128] Figure 1 and Figure 2 The present invention has been illustrated and preferred embodiments of the process of the present invention have been described.

[0129] Figure 1 A preferred embodiment of the process of the present invention is described, wherein (a), (b), (c), (d) and (e) represent steps (a), (b), (c), (d) and (e) as defined herein. (1) = introduction of a source of protein and digestible carbohydrates; (2) = optional introduction of a second source of protein and digestible carbohydrates; (3) = introduction of a lipid component; (4) introduction of a digestible carbohydrate component; (5) = optional introduction of a dietary fiber component; (6) = discharge of an infant formula product. Gas injection into the extruder is not shown.

[0130] Figure 2 A preferred embodiment of the process of the present invention is described, wherein (a), (b), (c) and (d) represent steps (a), (b), (c) and (d) as defined herein, (a') represents a step as defined herein in which the total solids content of the aqueous mixture is increased; (e1) represents a drying step as defined herein; (e2) represents a grinding step as defined herein. (1) = introduction of a source of protein and digestible carbohydrates; (2) = optional introduction of a second source of protein and digestible carbohydrates; (3) = introduction of a lipid component; (4) introduction of a digestible carbohydrate component; (5) = optional introduction of a dietary fiber component; (6) = discharge of an infant formula product. Gas injection into the extruder is not shown.

[0131] Example

[0132] The following examples illustrate the invention.

[0133] Example 1

[0134] A method flow for preparing an infant formula is produced, the infant formula being intended for infants aged 0 to 6 months. In a first step, demineralized whey (Demin Whey, flow rate 3166 kg / h), liquid whey protein concentrate 80 (WPC80, flow rate 430 kg / h), water (flow rate 677.2 kg / h) and a desired amount of micronutrients (i.e., vitamins and minerals) are mixed at a temperature of 35°C to form an aqueous liquid having a total solid content (% TS) of 25, and processed at a flow rate of 4419 kg / h.

[0135] The aqueous liquid was then heat treated at 121.0°C with a residence time of 2.89 seconds to obtain an F0 of 2.4. After cooling, the heated solution was then fed to an evaporator for concentration, during which water was removed at a flow rate of 1943.5 kg / h. After evaporation, the % TS of the aqueous solution was 44.6 and was delivered to an oil injector at a temperature of 60°C at a flow rate of 2475.5. The oil required for the preparation of the infant formula was injected into the aqueous stream at a flow rate of 2337.32 kg / h to obtain a % TS of 71.5. The solution was then fed to a homogenizer for homogenization and emulsification at 60°C using a flow rate of 4812 kg / h. The homogenized oil-in-water emulsion was delivered to an extruder.

[0136] During extrusion, whey protein concentrate (WPC35, flow rate 388.8 kg / h), whey protein concentrate powder (WPC80, flow rate 91.2 kg / h), skim milk powder (SMP, flow rate 1349.3 kg / h), lactose (1417.4 kg / h) and GOS (Vivinal GOS; 75% by weight of concentrated liquid, flow rate 1685.9 kg / h) were added. GOS was added as the final ingredient during extrusion. Extrusion was carried out at 63°C at a flow rate of 9745.6 kg / h. The extrudate obtained contained 80% TS and was ready to be dried using known techniques, such as flash drying or vacuum belt drying, to finally obtain a nutritional composition with a % TS of 97.5, which was prepared at a flow rate of 7996.4 kg / h. No dry mixing of other ingredients was required. A powdered composition ready for packaging was obtained.

[0137] Example 2

[0138] A method flow for preparing an infant formula is produced, which is intended for infants aged 6 to 12 months. In the first step, liquid whey protein concentrate 35 (WPC35, flow rate 1019.4 kg / h), water (flow rate 3140.7 kg / h) and a required amount of micronutrients (i.e. vitamins and minerals) are mixed at a temperature of 35°C to form an aqueous liquid having a total solid content (% TS) of 25 and processed at a flow rate of 4236.5 kg / h. The protein content of the aqueous liquid is 8.44% by weight.

[0139] The aqueous liquid was then heat treated at 121.0°C with a residence time of 2.89 seconds to obtain an F0 of 2.4. After cooling, the heated solution was then fed to an evaporator for concentration. After evaporation, water was removed during this period at a flow rate of 1703.1 kg / h, the % TS of the aqueous solution was 41.8, and it was delivered to an oil injector at a flow rate of 2533.4 at a temperature of 60°C. The oil required for the preparation of the infant formula was injected into the aqueous stream at a flow rate of 2029.82 kg / h to achieve a % TS of 67.69. The solution was then fed to a homogenizer and homogenized and emulsified at 60°C using a flow rate of 4563.2 kg / h. The homogenized oil-in-water emulsion was delivered to an extruder.

[0140] During extrusion, skimmed milk powder (SMP, flow rate 1633.45 kg / h), lactose (2472.24 kg / h) and GOS (Vivinal GOS; 75 wt% concentrated liquid, flow rate 1084.8 kg / h) were added. GOS was added as the final ingredient during extrusion. Extrusion was carried out at 65°C with a flow rate of 9753.68 kg / h. The extrudate obtained contained 80% TS and was ready to be dried using known techniques, such as flash drying or vacuum belt drying, to finally obtain a nutritional composition with a % TS of 97.5, which was prepared at a flow rate of 8003.0 kg / h. No dry blending of other ingredients was required. A powdered composition ready for packaging was obtained.

[0141] Example 3

[0142] The data mentioned in Examples 1 and 2 were generated using the gPROMS gFormulatedProducts 1.2.2 simulation model purchased from Process Systems Enterprise (PSE). The mass balance model used was steady-state, which means that time integration was not applied. The model was applied at the macro level without any discretization method.

[0143] For evaporation / concentration, the mass balance of equation (1) was used.

[0144]

[0145] It indicates the amount of water that evaporates or is otherwise removed from a stream. The amount of the outlet plus flow should be equal to the inlet flow. From this point of view, the outlet total solids are calculated by equation (2):

[0146]

[0147] This is applied under the assumption that the extracted water extracted by evaporation or any other technique is pure water.

[0148] The same method is used for mixing the different streams during mixing (i.e. preparation of the aqueous mixture before heat treatment step a), fat injection (i.e. step b) or extrusion (step d). Equation (3) applies to the overall mass balance:

[0149]

[0150] Where multiple inlet streams are used, the solids outlet volume for any mixer and / or extruder is calculated by adjusting equation (3):

[0151]

[0152] For the drying step, independent of the drying technique, equations 1 and 2 were applied to calculate the evaporation capacity of water.

[0153] These equations are applied in the construction of the flowsheet. The information transferred between the models for the product streams is the mass flow rate and composition (kg / kg).

[0154] Example 4

[0155] A method flow for preparing an infant formula is generated, and the infant formula is intended for infants aged 0 to 6 months. First, at a temperature of 29° C., 40 kg of a mixture of desalted whey and minerals (95% TS) is mixed into 35 kg of water to obtain a solution having a total solid content of 51% TS. The wet phase is then fed into an oiler and a homogenizer. The 39 kg of oil required for preparing the infant formula is injected into an aqueous stream to obtain an emulsion of 113 kg of 68% TS. The solution is then homogenized at 60° C. The viscosity of the homogenized emulsion is measured to be 107 kcP (measured at 42° C. in a rotational viscometer).

[0156] The homogenized oil-in-water emulsion was fed to the extruder at a flow rate of 12.2 kg / h. During extrusion, GOS (Vivinal GOS; 75% TS concentrated liquid, flow rate 3.3 kg / h), lactose (95% TS; 2.6 kg / h) and skim milk powder (SMP, 95% TS; 1.8 kg / h) were added. The extruder was heated at 550 rpm and 55°C → 65°C → T g Extrusion was performed under a temperature gradient, using 30 L / h N2 or 50 L / h CO2 as the inflation gas. gThe gas was injected at 60°C for N2 and 35°C for CO2. The viscosity of the N2-aerated extrudate was measured to be 4.2 kcP (measured in a rotational viscometer at 53°C), and the viscosity of the CO2-aerated extrudate was measured to be 8.4 kcP (measured in a rotational viscometer at 46°C). The extrudate obtained contained 75% TS and was spray-dried at a rate of 20 kg / h at 125-130°C and 8 bar atomizing pressure to finally obtain an infant formula base powder containing 98% TS.

[0157] Example 5

[0158] The bulk volume and granule density of the infant formula base powder obtained in Example 4 and the control infant formula base powder not subjected to extrusion were measured. The bulk volume was determined according to IDF guideline ISO8967, and the granule density was determined using a gas pycnometer UltraPyc1200E.

[0159] The bulk volume indicates the amount of volume occupied by 100 g of powder in ml, while the particle density indicates the porosity of the powder. Both can be used as an indicator of the wettability of the powder. The table below shows that the pouring and loose bulk volumes of the aerated powders are not strongly affected by the process of the present invention compared to the spray-dried control powders. In addition, aeration with N2 does not affect the particle size density of the powders, while the powders aerated with CO2 have lower particle density and therefore higher porosity.

[0160] Powder Characterization

[0161]

[0162] Example 6

[0163] The free fat content of the infant formula base powder obtained in Example 4 and a control infant formula base powder which was not extruded was measured following the instructions in the GEA Niro analytical method Nr.A 10b.

[0164] It is preferred that the amount of free fat is as low as possible, as free fat is susceptible to oxidation during storage. From the table below it can be observed that both powders aerated with N2 or CO2 have free fat levels below 2%, thus meeting the preferred requirements for a stable infant formula powder.

[0165] Free fat analysis

[0166] Free fat (%) <![CDATA[N2 gas injection]]> 1.5 <![CDATA[CO2 gas injection]]> 1.9 Comparison 0.5

[0167] Example 7

[0168] The wettability and reconstitution properties of the infant formula powder obtained in Example 4 and of a control infant formula which was not extruded were measured following the guidelines in the GEA Niro analytical method Nr. A 5b and the IDF guidelines.

[0169] Wettability refers to the time required for a powder to sink into water upon reconstitution and represents an important feature of the user experience (see Example 9 below). Powders aerated with CO2 gas had a wettability of more than 120 seconds, while powders aerated with N2 had improved wettability compared to the control. In addition, the reconstitution analysis showed that the reconstitution behavior was adequate for all powders tested, with the aerated powders of the present invention performing slightly better than the control powders. Reconstitution values ​​of 1 or less correspond to excellent reconstitution properties. In summary, the powders obtained by the method of the present invention exhibited the desired reconstitution behavior without undesirable agglomeration or adhesion.

[0170] Wettability and recovery properties

[0171] Average wettability(s) Average recovery <![CDATA[N2 gas injection]]> 7 1 <![CDATA[CO2 gas injection]]> >120 0.5 Comparison 12 1

[0172] Example 8

[0173] The infant formula powder obtained in Example 4 and a control infant formula without extrusion were further tested in the user experience evaluation. A dedicated milk panel consisting of 8 members developed specific language for testing 16 attributes. A total of 5 attribute generation and training sessions were conducted, followed by 1 analysis session, in which 16 attributes of 3 products were evaluated blindly.

[0174] In most attributes, there were no significant differences in the performance of the three test formulas, but some notable differences were observed in terms of foaming behavior and sinking speed. The formation of foam after reconstitution of the powder is undesirable for the user because the foam remains in the bottle to a large extent during the feeding event. In addition, a faster collapse of the foam is preferred because the user usually does not wait for the foam to collapse before starting to feed the baby. From the following table, it can be concluded that the aerated powder obtained according to the present invention results in a reduction in the total amount of foam compared to the control formula. In addition, the foam seems to be less stable when using the method of the present invention because the amount of foam decreases rapidly over time. Both aerated formulas of the present invention are superior to the control formula, with the performance of the CO2 aerated formula being slightly better than the N2 aerated formula.

[0175] The sinking speed of the powdered infant formula is comparable to the wettability described above. The sinking speed is measured as the speed at which the powder sinks through the water in the bottle after the sixth scoop is added. The lower the sinking speed, the faster the powder sinks in the fluid. The powder aerated with CO2 gas has the highest sinking speed, i.e., sinks the slowest, while the powder aerated with N2 gas sinks the fastest. These results are consistent with the results obtained in the wettability experiment.

[0176] User experience results

[0177]

Claims

1. A method for preparing an infant formula product, comprising the steps of: (a) subjecting an aqueous mixture having a protein component and a carbohydrate component to a heat treatment step, (b) mixing the aqueous mixture with a lipid component, (c) subjecting the aqueous mixture comprising the lipid component, the carbohydrate component and the heat-treated protein component to a homogenization and emulsification step to obtain a homogenized oil-in-water emulsion having a total solid content of 45-73% by weight; (d) conveying the homogenized emulsion into an extruder, independently adding a digestible carbohydrate and optionally a dietary fiber into the extruder, and extruding the contents of the extruder to obtain an extruded aerated material, wherein a gas is injected into the extruder; (e) preparing an infant formula product from the extruded aerated material; wherein the entire process, except for the heat treatment in step (a), does not exceed 75°C; and Therein, the extruded aerated material contains substantially all the protein and / or lipid required nutritionally for the infant formula.

2. The method of claim 1, wherein step (e) comprises spray drying the extruded material.

3. The method according to claim 1 or 2, wherein the weight ratio of whey protein to casein of the protein component of the infant formula is from 9 / 1 to 1 / 9.

4. The method according to claim 1 or 2, wherein the weight ratio of whey protein to casein of the protein component of the infant formula is 5 / 1 to 1 / 5.

5. The method according to claim 1 or 2, wherein the weight ratio of whey protein to casein of the protein component of the infant formula is 3 / 1 to 1 / 1.

6. The method according to claim 1 or 2, wherein the weight ratio of whey protein to casein of the protein component of the infant formula is 6 / 4.

7. The method according to claim 1 or 2, wherein the total solid content of the homogenized oil-in-water emulsion in step (c) is 53-68% by weight.

8. The method according to claim 1 or 2, wherein the total solid content of the homogenized oil-in-water emulsion in step (c) is 60-65% by weight.

9. The method according to claim 1 or 2, wherein in step (d) the digestible carbohydrates are added in the form of a dry powder and the dietary fiber is added in the form of a dry powder or a concentrated liquid.

10. The method according to claim 1 or 2, wherein the digestible carbohydrate is lactose and / or maltodextrin.

11. The method according to claim 10, wherein in step (d) the digestible carbohydrates are added in the form of a dry powder and the dietary fiber is added in the form of a dry powder or a concentrated liquid.

12. The method according to claim 1 or 2, wherein the heat treatment of step (a) is designed to obtain a microbiologically safe protein component.

13. The method according to claim 1 or 2, wherein the heat treatment of step (a) is designed to obtain a microbiologically safe protein component and is performed by pasteurization, UHT, HTST or ESL.

14. The method according to claim 1 or 2, wherein the total solid content of the aqueous mixture in step (a) is 15-40% by weight.

15. The method according to claim 1 or 2, wherein the total solid content of the aqueous mixture in step (a) is 20-35% by weight.

16. The method according to claim 1 or 2, wherein the total solid content of the aqueous mixture of step (a) is 25-32% by weight.

17. The method of claim 1 or 2, wherein the aqueous mixture subjected to step (b) has a total solids content of 35-60 wt% prior to mixing with the lipid component.

18. The method of claim 1 or 2, wherein the aqueous mixture subjected to step (b) has a total solids content of 40-55 wt% prior to mixing with the lipid component.

19. The method of claim 1 or 2, wherein the aqueous mixture subjected to step (b) has a total solids content of 45-51 wt% prior to mixing with the lipid component.

20. The method according to claim 1 or 2, wherein the total solid content of the aqueous mixture obtained in step (a) is increased before mixing with the lipid component.

21. The method according to claim 1 or 2, wherein the total solid content of the aqueous mixture obtained in step (a) is increased by an evaporation step before mixing with the lipid component.

22. The method according to claim 1 or 2, wherein skim milk and / or whey protein concentrate (WPC) is used as a source of the protein component and the carbohydrate component of the aqueous mixture subjected to step (a).

23. The method of claim 1 or 2, wherein the carbohydrate component in step (a) comprises lactose, which accounts for 15 to 75% by weight of the total lactose content of the infant formula product prepared in step (e).

24. A method according to claim 1 or 2, wherein the carbohydrate component in step (a) comprises lactose which constitutes 15 to 75 wt% of the total lactose content of the infant formula product prepared in step (e), and wherein the remaining lactose is added in step (d) and / or step (e).

25. The method according to claim 1 or 2, wherein the digestible carbohydrates added during step (d) comprise lactose, and the amount of lactose added during step (d) is 0 to 80 wt.% (on a dry weight basis) of the total amount of lactose contained in the infant formula product obtained in step (e).

26. The method according to claim 1 or 2, wherein the digestible carbohydrates added during step (d) comprise lactose, and the amount of lactose added during step (d) is 25 to 50 wt.% (on a dry weight basis) of the total amount of lactose contained in the infant formula product obtained in step (e).

27. The method according to claim 1 or 2, wherein the digestible carbohydrates added during step (d) comprise lactose, and the amount of lactose added during step (d) is 0 to 40 wt. % based on the total dry weight of the infant formula product obtained in step (e).

28. The method according to claim 1 or 2, wherein the digestible carbohydrates added during step (d) comprise lactose, and the amount of lactose added during step (d) is 0 to 30 wt. % based on the total dry weight of the infant formula product obtained in step (e).

29. An infant formula product obtainable by the process according to claim 1.

30. An infant formula product obtainable by the process according to claim 2.

31. An infant formula product according to claim 29 or 30 which is an infant formula, a follow-on formula, a toddler milk or a growing-up milk.

32. An infant formula product according to claim 29 or 30, wherein the extruded material is nutritionally complete when it leaves the extruder and nutritionally meets the requirements of an infant formula.

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