Preparation of high solids and high protein lactose-free aseptic milk concentrate and powder using forward osmosis

Abstract

The present invention discloses a method for preparing a sterile dairy composition by subjecting a dairy product to forward osmosis followed by a heat treatment step, the sterile dairy composition having at least 35% by weight solids, and typically 40 to 50% by weight solids. The heat treatment step may include UHT sterilization via direct steam injection or direct steam injection. Subsequently, the sterile dairy composition may be dried to form a milk powder composition.

Description

[0001] Citation to Related Applications

[0002] This application was filed as a PCT international patent application on December 15, 2020, and claims priority to U.S. Provisional Patent Application No. 62 / 950,161 filed on December 19, 2019, the disclosure of which is incorporated herein by reference in its entirety. Field of the Invention

[0003] The present invention relates generally to concentrated dairy compositions and more particularly to the use of forward osmosis technology for preparing high solids dairy compositions and dry or powdered dairy compositions. Background of the Invention

[0005] Membrane filtration methods are non-thermal fractionation and concentration techniques for fluids. When a fluid is passed through a semipermeable membrane under pressure, the components retained on the membrane surface are referred to as the retentate or concentrate, while the material that passes through the membrane is collectively referred to as the permeate. Membrane techniques generally do not involve heat or chemicals for fractionation or concentration, and therefore do not adversely affect the properties of the fluid, which is beneficial to milk and its components. When fluids (such as milk) are fractionated by these membrane techniques, proteins are generally not denatured, enzymes are not inactivated, vitamins are not destroyed, and no reaction occurs between proteins and sugars. SUMMARY OF THE INVENTION

[0007] This summary is provided to introduce a selection of some concepts further described herein in a simplified form. This summary is not intended to identify required or essential features of the claimed subject matter. This summary is also not intended to be used to limit the scope of the claimed subject matter.

[0008] Consistent with embodiments of the present invention, a method for preparing a sterile dairy composition is disclosed. The method may include (a) subjecting a dairy product to forward osmosis to form a dairy concentrate having at least about 35% by weight solids, and (b) heat treating the dairy concentrate to form the sterile dairy composition. Typically, the dairy concentrate may have about 35 to about 60% by weight solids after step (a), and more often about 40 to about 50% by weight solids, and step (b) may include UHT sterilization using indirect heating, direct steam jet, or direct steam injection.

[0009] Advantageously and unexpectedly, the forward osmosis step can remove more than 50% of the water from the dairy product, and in some cases remove up to 70-80% of the water from the dairy product, resulting in a milk concentrate having a much higher solids content than can be achieved using reverse osmosis. The concentrate can then be dried to form a dry milk powder composition.

[0010] Both the preceding summary and the following detailed description provide examples and are illustrative only. Therefore, the preceding summary and the following detailed description should not be considered restrictive. In addition, features or variations other than those set forth herein may also be provided. For example, certain embodiments may relate to various feature combinations and sub-combinations described in the detailed description.

[0011] definition

[0012] In order to more clearly define the terms used herein, the following definitions are provided. Unless otherwise indicated, the following definitions apply to the present invention. If a term is used in the present invention but is not specifically defined herein, the IUPAC Compendium of Chemical Terminology, 2nd Edition (1997) may be used. nd Ed (1997)), so long as that definition does not conflict with any other disclosure or definition applied herein or render uncertain or unenforceable any claim to which that definition applies. To the extent any definition or usage provided by any document incorporated by reference conflicts with the definition or usage provided herein, the definition or usage provided herein controls.

[0013] In this article, the features of the subject matter are described so that in particular aspects and / or embodiments, combinations of different features can be envisioned. For each aspect and / or embodiment and / or feature disclosed herein, with or without an explicit description of a particular combination, all combinations that do not adversely affect the design, composition, process and / or method described herein are considered. In addition, unless otherwise explicitly stated, any aspect and / or embodiment and / or feature disclosed herein can be combined to describe an inventive design, composition, process and / or method consistent with the present invention.

[0014] In the present invention, although compositions and methods are often described in a manner of “comprising” various components or steps, unless otherwise specified, the compositions and methods may also “consist essentially of” or “consist of” the various components or steps.

[0015] Unless otherwise specified, the terms "a", "an", and "the" are intended to include plural alternatives, such as at least one alternative. For example, unless otherwise specified, disclosure of "an ingredient" is intended to encompass one ingredient, or a mixture or combination of more than one ingredient.

[0016] In the disclosed methods, unless otherwise indicated, the term "combining" encompasses contacting or adding the components in any order, in any manner, and for any length of time. For example, the components can be combined by blending or mixing.

[0017] "Lactose fraction" is meant to encompass fractions of milk (milk) components enriched in lactose or any derivative thereof, e.g., hydrolyzed, unhydrolyzed, epimerized, isomerized or converted to oligosaccharides, as will be appreciated by those skilled in the art. In addition, unless otherwise indicated, the term is also meant to encompass glucose / galactose, such as may be produced by treating lactose with lactase.

[0018] Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the typical methods and materials are described herein.

[0019] A variety of numerical ranges are disclosed herein. Unless otherwise stated, when any type of scope is disclosed or claimed herein, it is intended to disclose or claim individually each possible numeral that such a scope can reasonably cover, including the endpoints of the scope and any sub-range and the combination of sub-ranges covered therein. As a representative example, the application discloses that dairy products can have about 3 to about 10 weight % protein in certain embodiments. By disclosing the protein content of dairy products, it can be in the range of about 3 to about 10 weight %, and it is intended to record that protein content can be any amount in the range, and for example can be equal to about 3, about 4, about 5, about 6, about 7, about 8, about 9 or about 10 weight %. In addition, dairy products can contain the protein amount in any range of about 3 to about 10 weight % (for example, about 3 to about 6 weight %), and this also includes any combination of the scope of about 3 to about 10 weight %. In addition, in all cases, when disclosing "about" specific value, the value itself is disclosed. Therefore, the disclosure of a protein content of about 3 to about 10 wt % also discloses a protein content of 3 to 10 wt % (e.g., 3 to 6 wt %), and this also includes any combination of ranges from 3 to 10 wt %. Likewise, all other ranges disclosed herein should be interpreted in a manner similar to this example.

[0020] The term "about" means that the amount, size, formula, parameter and other quantities and characteristics are not and need not be exact, but may be approximate, including increasing or decreasing as needed, reflecting tolerances, conversion factors, rounding, measurement errors, etc., and other factors known to those skilled in the art. Generally, whether or not explicitly stated, the amount, size, formula, parameter or other quantity or characteristic is "about" or "approximate". The term "about" also covers differences in quantity due to different equilibrium conditions of the composition obtained from a particular initial mixture. Whether or not modified by the term "about", the claims include equivalents of the quantity. The term "about" can mean within 10% of the reported value, preferably within 5% of the reported value. DETAILED DESCRIPTION OF THE INVENTION

[0022] Methods for preparing high solids sterilized dairy compositions are disclosed and described herein. Such methods can utilize a forward osmosis step to produce a high solids dairy concentrate, followed by a heat treatment step to form a high solids sterilized dairy composition. Optionally, the dairy composition can be dried to form a dried dairy composition (also referred to herein as a milk powder composition).

[0023] Forward osmosis (FO) is a low-pressure membrane process in which the driving force for water transfer is the activity of water passing through a semipermeable membrane. Water transfer passes through a semipermeable membrane from the feed side (low ion concentration or low osmotic pressure) to the draw liquid side (high ion concentration or high osmotic pressure) until the osmotic pressure difference between the two sides is close to zero. Relative to reverse osmosis, the advantages of forward osmosis are many. Forward osmosis uses a low operating pressure, which reduces energy consumption. Compared with the thermal evaporation process, forward osmosis is carried out at a lower temperature (e.g., ambient temperature or lower), so this can prevent the quality deterioration of milk components that may cause discoloration, odor and taste changes. In addition, compared with other filtration technologies, forward osmosis has a higher product recovery rate, making the environmental impact smaller. Compared with other filtration technologies (particularly reverse osmosis), the amount of dirt in forward osmosis is much lower and reversible, thereby saving the cost and time of membrane cleaning and replacement.

[0024] Advantageously and unexpectedly, the milk starting material can be efficiently concentrated to a much higher solids content than can be achieved using reverse osmosis. Because the resulting product has a high solids content, transportation costs are reduced. And finally, the size of a forward osmosis module is smaller than a reverse osmosis and evaporation unit.

[0025] In this article, several examples of forward osmosis methods are disclosed, in which the reverse osmosis step is replaced by the forward osmosis step to concentrate the stream that can be obtained by the classification of milk components. First, raw milk can be subjected to fat separation to obtain cream and skim milk. Then, skim milk can be subjected to ultrafiltration to produce ultrafiltration retentate and ultrafiltration permeate. Then, the ultrafiltration permeate can be subjected to nanofiltration, and then the nanofiltration permeate is subjected to forward osmosis to concentrate minerals. Water diffuses into the draw liquid (e.g., 65% potassium lactate, saline, etc.) through a polymer membrane, and minerals are concentrated on the other side of the membrane. The water in the diluted draw liquid can be removed by reverse osmosis or thermal evaporation. The recovered draw liquid can be recycled for future use. The mineral content in dairy products can usually be doubled, tripled, quadrupled, etc.

[0026] In other examples, the ultrafiltration retentate and permeate can be concentrated to 30-50% by weight solids by forward osmosis to improve the efficiency of operation and transportation. The concentrated ultrafiltration retentate can be characterized as a highly concentrated milk protein concentrate. The nanofiltration retentate can be concentrated to 50% by weight solids or more from less than 15% by weight solids to produce a highly concentrated lactose product. In addition, consistent with the methods disclosed herein, skim milk can be concentrated to up to 48-50% by weight solids by forward osmosis and then spray dried to 95-97% by weight solids.

[0027] According to an embodiment of the present invention, the method for preparing a sterile dairy composition may include the following steps (or consist essentially of the following steps, or consist of the following steps): (a) subjecting a dairy product to forward osmosis to form a milk concentrate having at least about 35% by weight of solids, and (b) heat treating the milk concentrate to form a sterile dairy composition. Generally, the features of these methods (e.g., the characteristics of the dairy product, the characteristics of the milk concentrate, the characteristics of the sterile dairy composition, heat treatment conditions and solid content, etc.) are described independently herein, and these features can be combined in any combination to further describe the disclosed method. In addition, unless otherwise stated, other method steps can be performed before, during and / or after any step listed in the disclosed method. In addition, any sterile dairy composition (e.g., a finished dairy product, ready for consumption) produced according to any disclosed method is within the scope of the present invention and is encompassed herein.

[0028] Filtration techniques (e.g., ultrafiltration, nanofiltration, forward osmosis, etc.) can separate or concentrate components in a mixture (such as milk) by passing the mixture through a membrane system (or selective barrier) under appropriate conditions (e.g., pressure). Concentration / separation can generally be based on molecular size. The stream retained by the membrane is called the retentate (or concentrate).

[0029] The dairy product in step (a) may comprise (or consist essentially of, or consist of) skimmed milk or, alternatively, whole milk. In some embodiments, the method may further comprise the step of separating (e.g., centrifuging) raw or fresh milk (whole milk) into a dairy product (also referred to as skimmed milk) and a fat-rich fraction (also referred to as cream or butter fat). Raw or fresh milk (whole milk) may be cow's milk, which contains approximately 87% by weight of water, 3-4% by weight of protein, 4-5% by weight of carbohydrates / lactose, 3-4% by weight of fat, and 0.3-0.8% by weight of minerals. When fresh milk or a raw milk product is separated into a skim milk product and a fat-rich fraction, the fat-rich fraction generally contains high levels of fat (e.g., 20-50 wt. % fat or 30-50 wt. % fat) and solids (e.g., 30-60 wt. % or 40-55 wt. %), and generally contains approximately 1.5-4 wt. % protein, 2-5 wt. % lactose, and 0.2-0.9 wt. % minerals, but is not limited thereto.

[0030] Raw milk itself or after pasteurization can be concentrated by forward osmosis to prepare sterile whole milk concentrate or milk powder. The forward osmosis process during powder manufacturing eliminates the step of concentrating milk by thermal evaporation under vacuum, because forward osmosis can match the concentration of milk solids obtained by thermal evaporation. Combining reverse osmosis and thermal evaporation of milk to concentrate milk before milk is spray-dried into milk powder can reduce energy costs and improve milk powder quality. However, forward osmosis can eliminate reverse osmosis and thermal evaporation steps during milk powder manufacturing, which can further reduce energy costs and improve milk powder quality. During thermal evaporation, some volatiles of fresh milk are lost due to heat condensation under vacuum. Since heat or vacuum is not required during forward osmosis treatment, fresh milk volatiles will be retained in the powder finally obtained by using forward osmosis.

[0031] Representative and non-limiting examples of (milk-based) dairy products that can be used in the methods disclosed herein may include whole milk, low-fat milk, skim milk, buttermilk, flavored milk, low-lactose milk, high-protein milk, lactose-free milk, ultrafiltered milk, microfiltered milk, or high-protein lactose-free skim milk, etc.

[0032] Although not limited thereto, the dairy product can have a protein content of about 1 to about 15 % by weight or about 3 to about 10 % by weight. In some embodiments, the dairy product can have a protein content of about 2 to about 8 % by weight, such as about 3 to about 6 % by weight protein. Additionally or alternatively, the dairy product can have a fat content of about 0.05 to about 10 % by weight or about 0.1 to about 5 % by weight fat. Additionally or alternatively, the dairy product can have a mineral content of about 0.5 to about 2 % by weight, about 0.5 to about 1.5 % by weight or about 0.5 to about 1 % by weight minerals. Additionally or alternatively, the dairy product can have a lactose content of less than or equal to about 6 % by weight or less than or equal to about 4 % by weight, and in some embodiments less than or equal to about 1 % by weight or less than or equal to about 0.1 % by weight lactose.

[0033] Before forward osmosis, the typical solid content of the dairy product can be in the range of about 5 to about 15 weight % solids or about 6 to about 12 weight %. In some embodiments, the solid content of the dairy product can be in the range of about 7 to about 10 weight % or about 8 to about 10 weight % solids.

[0034] Representative and non-limiting examples of dairy products consistent with the present invention can contain less than or equal to about 0.5% by weight of fat, about 2 to about 8% by weight of protein, about 0.5 to about 2% by weight of minerals and less than or equal to about 6% by weight of lactose. Another representative and non-limiting example of dairy products consistent with the present invention can contain about 0.5 to about 1.5% by weight of fat, about 2 to about 8% by weight of protein, about 0.5 to about 2% by weight of minerals and less than or equal to about 6% by weight of lactose. In addition, another representative and non-limiting example of dairy products consistent with the present invention can contain about 1.5 to about 2.5% by weight of fat, about 2 to about 8% by weight of protein, about 0.5 to about 2% by weight of minerals and less than or equal to about 6% by weight of lactose. In addition, another representative and non-limiting example of dairy products consistent with the present invention can contain about 2.5 to about 5% by weight of fat, about 2 to about 8% by weight of protein, about 0.5 to about 2% by weight of minerals and less than or equal to about 6% by weight of lactose.

[0035] Optionally, the disclosed method may further comprise the steps of treating (combining) the dairy product with lactase before step (a) to form a dairy product having less than 0.1% by weight of lactose and in some cases less than 0.05% by weight of lactose or less than 0.01% by weight of lactose. Therefore, before forward osmosis, the dairy product may be combined with lactase to form a lactose-free dairy product. Alternatively, after the forward osmosis step (a), but before the heat treatment in step (b), the milk concentrate may be treated with lactase, or after step (b), the aseptic dairy composition may be treated with lactase. After ultra-high temperature heat treatment, lactase may be dosed into the aseptic dairy composition using an aseptic dosing system. Typically, the treatment with lactase is performed before the forward osmosis step.

[0036] In step (a), the dairy product can be subjected to a forward osmosis step to produce a milk concentrate, which generally has at least 35% by weight of solids. In addition, water can be removed from the dairy product in the forward osmosis step to form a dilute draw solution. Forward osmosis is generally carried out at a much lower pressure than standard reverse osmosis (and uses less energy), and utilizes a semi-permeable membrane system, the pore size of which allows water to pass through, while other substances (e.g., protein, fat, lactose or other sugars and minerals) do not pass through. Operating pressure is generally less than or equal to about 75 psig, less than or equal to about 60 psig, less than or equal to about 45 psig, less than or equal to about 30 psig, or less than or equal to about 15 psig. Exemplary and non-limiting ranges of operating pressures for the forward osmosis step include about 0 psig (atmospheric pressure) to about 75 psig, about 0 psig to about 45 psig, about 1 psig to about 60 psig, about 1 psig to about 30 psig, about 1 psig to about 15 psig, about 10 psig to about 75 psig, about 15 to about 60 psig, and the like.

[0037] Although not limited thereto, the forward osmosis step can be performed at a temperature in the following range: about 5 to about 50°C; alternatively, about 10 to about 40°C; alternatively, about 8 to about 25°C; alternatively, about 8 to about 20°C; or alternatively, about 5 to about 15°C. In addition, without limitation thereto, the molecular weight cutoff of the forward osmosis membrane system is much less than 100Da, and thus components other than water (e.g., minerals) can be concentrated during the forward osmosis process. Typically, the forward osmosis comprises a membrane system having a pore size less than or equal to about 0.001 μm.

[0038] Compared to reverse osmosis, the forward osmosis step consistent with the embodiments of the present invention can effectively achieve higher solid content and higher mineral content. In addition, compared to reverse osmosis, there is less fouling during forward osmosis, and the fouling can be easily removed, resulting in lower costs for membrane cleaning and replacement and less downtime. In addition, the size and footprint of the forward osmosis system are generally smaller than the reverse osmosis system, so it can be retrofitted in small or crowded spaces.

[0039] Any suitable draw solution having a higher solute or ion concentration than the solution from which water is extracted through the semipermeable membrane can be used for the forward osmosis step. Typically, solutions containing high concentrations of monovalent ions, such as sodium, potassium, chloride, etc., and combinations thereof, can be used. Additionally or alternatively, the draw solution may contain high concentrations of any suitable sugar, representative examples of which may include sucrose, glucose, galactose, lactose, fructose, maltose, etc., and combinations thereof. In some embodiments, the draw solution may include potassium lactate, etc., while in other embodiments, the forward osmosis draw solution may include concentrated milk minerals. For example, the forward osmosis draw solution may include about 5 to about 60% by weight of milk minerals; alternatively, about 10 to about 50% by weight of milk minerals; alternatively, about 18 to about 32% by weight of milk minerals; alternatively, about 0.3 to about 5% by weight of milk minerals; alternatively, about 0.3 to about 3% by weight of milk minerals; or alternatively, about 0.4 to about 1.5% by weight of milk minerals. The forward osmosis draw liquid can include, in one embodiment, a RO retentate fraction, in another embodiment, a NF permeate fraction of a UF permeate fraction, or a mixture or combination of a RO retentate fraction and a NF permeate fraction. In another embodiment, for example, the draw liquid can be a mineral concentrate prepared using reverse osmosis or prepared using forward osmosis. In another embodiment, the draw liquid can be a mixture of a NF permeate fraction of a RO mineral concentrate and a UF permeate fraction or a concentrated NF permeate fraction. In yet another embodiment, the draw liquid can be the hydrolysis NF retentate fraction of a UF permeate fraction, optionally concentrated to a higher solid content.

[0040] The concentration difference between the feed stream (e.g., dairy product) and the draw solution is used to remove water from the feed stream. Typically, when there is a semipermeable membrane or barrier (e.g., polymer membrane) between the two solutions, forward osmosis moves water from a lower concentration solution (feed side) to a higher concentration solution (draw solution) by osmotic pressure. Therefore, the solids, minerals and other non-aqueous components of the feed stream (e.g., dairy product) are concentrated in forward osmosis to obtain the milk concentrate described herein.

[0041] In step (a), subjecting the dairy product to forward osmosis can form a milk concentrate and a diluted draw solution. Optionally, the diluted draw solution produced by forward osmosis can undergo a step of removing at least a portion of water from the diluted draw solution to form a draw solution. The draw solution can be reused in the forward osmosis step. In one embodiment, removing at least a portion of water from the diluted draw solution can include subjecting the diluted draw solution to reverse osmosis. Reverse osmosis is a fine filtration process or concentration process, in which substantially all components are retained (retentate) except for water passing through a reverse osmosis membrane. Typically, the molecular weight cutoff of the reverse osmosis membrane system is much less than 100Da, and therefore components other than water (e.g., minerals) are concentrated during the reverse osmosis process. Typically, reverse osmosis includes a membrane system having a pore size less than or equal to about 0.001 μm. The operating pressure is typically in the range of 450-1500 psig or 450-600 psig. A temperature in the range of about 5 to about 45°C or about 15 to about 45°C can typically be used.

[0042] Alternatively, removing at least a portion of the water from the diluted draw solution may include subjecting the diluted draw solution to evaporation. Although not limited thereto, temperatures above 50° C. and pressures below atmospheric pressure are typically employed. Whether evaporation or reverse osmosis, the resulting water fraction is substantially free of all milk components and draw solution components (which come from forward osmosis). Thus, the water fraction may be substantially all water, such as at least about 99% by weight water, at least about 99.5% by weight water, or at least about 99.8% by weight water.

[0043] Advantageously, the milk concentrate (or sterile milk composition) after forward osmosis can have a weight % solid content that is unexpectedly greater than the weight % solid content that can be achieved using reverse osmosis. The milk concentrate (or sterile milk composition) can have at least about 35 weight % solids, at least about 37 weight % solids, at least about 38 weight % solids, at least about 40 weight % solids, or at least about 42 weight % solids, and typically less than or equal to about 60 weight % solids, less than or equal to about 55 weight % solids, less than or equal to about 50 weight % solids, or less than or equal to about 48 weight % solids. Representative and non-limiting ranges of the solid content of the milk concentrate (or sterile composition) can include about 35 to about 60 weight % solids, about 35 to about 50 weight % solids, about 35 to about 48 weight % solids, about 38 to about 48 weight % solids, about 40 to about 55 weight % solids, about 40 to about 50 weight % solids, about 42 to about 55 weight % solids, etc.

[0044] Unexpectedly, the forward osmosis step disclosed herein is a very effective technique for increasing the solid content (or protein content, or mineral content) of an incoming dairy product feed stream. Concentration factors of at least about 2, at least about 3, at least about 3.5, at least about 4, at least about 4.5, and at least about 5 can be achieved via the forward osmosis step disclosed herein, and typically the concentration factor can be as high as about 6, 7, 8, 9, or 10 in a particular embodiment. These concentration factors apply to both a weight % solids basis and a weight % protein and a weight % mineral basis. For example, a dairy product having 0.8 weight % minerals, 3.4 weight % protein, and 9.2 weight % solids is subjected to forward osmosis to obtain a milk concentrate (or sterilized dairy composition) having 3.6 weight % minerals, 17 weight % protein, and 44 weight % solids, which will be converted to a concentration factor of 4.5 based on minerals, a concentration factor of 5 based on protein, and a concentration factor of 4.8 based on solids.

[0045] The forward osmosis step can result in a significant volume reduction of the dairy product (e.g., removal of water therefrom). For example, the volume of the milk concentrate (or sterilized dairy composition) can be less than or equal to about 60% of the volume of the dairy product; alternatively, less than or equal to about 50% of the volume of the dairy product; alternatively, less than or equal to about 40% of the volume of the dairy product; alternatively, less than or equal to about 30% of the volume of the dairy product; or alternatively, less than or equal to about 20-25% of the volume of the dairy product. As shown in a construction example comparing conventional reverse osmosis and forward osmosis (see Table VI), forward osmosis can remove 87% of the water from skim milk, compared to only 67% of the water removed by conventional reverse osmosis.

[0046] Although not limited thereto, the milk concentrate (or sterilized dairy composition) can have a protein content of about 12 to about 32 % by weight or about 14 to about 28 % by weight. In some embodiments, the milk concentrate (or sterilized dairy composition) can have a protein content of about 12 to about 20 % by weight or about 20 to about 30 % by weight protein. Additionally or alternatively, the milk concentrate (or sterilized dairy composition) can have a fat content of about 0.05 to about 10 % by weight or about 0.1 to about 5 % by weight fat. Additionally or alternatively, the milk concentrate (or sterilized dairy composition) can have a mineral content of about 2 to about 5 % by weight, about 2.2 to about 4.8 % by weight or about 2.5 to about 4.5 % by weight minerals. Additionally or alternatively, the milk concentrate (or sterilized dairy composition) can have a carbohydrate content of about 2 to about 30 % by weight, such as about 5 to about 15 % by weight or about 20 to about 30 % by weight carbohydrates.

[0047] As discussed herein, after forward osmosis, the milk concentrate (and therefore the sterilized dairy composition) can have a very high solids content, which generally falls within the range of about 35-60% by weight. For example, in one embodiment, the milk concentrate (or sterilized dairy composition) can have a solids content of about 38 to about 50% by weight, while in another embodiment, the milk concentrate (or sterilized dairy composition) can have a solids content of about 40 to about 55% by weight.

[0048] The mineral content of the milk concentrate (and sterilized dairy composition) is significantly increased via forward osmosis. For specific minerals in the milk concentrate (or sterilized dairy composition), the sodium content can be in the range of about 800 to about 2000 ppm (or about 1000 to about 1800 ppm) by weight, while the potassium content can be in the range of about 5000 to about 9500 ppm (or about 6000 to about 9000 ppm), and the calcium content can be in the range of about 3000 to about 8000 ppm (or about 4000 to about 7000 ppm).

[0049] In step (b) of the method disclosed herein, the milk concentrate may be heat treated to form a sterilized milk composition. In one embodiment, the heat treatment step may include pasteurizing at a temperature in the range of about 80°C to about 95°C for a period of time in the range of less than 1 minute to about 15 minutes, such as about 2 to about 15 minutes. In another embodiment, the heat treatment step may include UHT sterilization at a temperature in the range of about 135°C to about 145°C for a period of time in the range of about 1 to about 10 seconds. In yet another embodiment, the heat treatment step may include UHT sterilization at a temperature in the range of about 148°C to about 165°C for a period of time in the range of about 0.05 to about 1 second, for example, about 150°C to about 155°C for a period of time in the range of about 0.08 to about 0.2 seconds. Other suitable pasteurization or sterilization temperature and time conditions are apparent from the present invention. In addition, the present invention is not limited by the method or equipment used to perform the pasteurization / sterilization process—any suitable technique and apparatus may be employed, whether batch operation or continuous operation.

[0050] Typical UHT sterilization techniques include indirect heating, direct steam injection, direct steam injection, etc. For indirect heating, the dairy concentrate is not in direct contact with a heat source or heating medium, such as a heat exchanger. Due to heat transfer limitations, indirect heating requires a longer sterilization time. Advantageously, in some aspects of the present invention, direct UHT sterilization is used to heat treat the dairy concentrate. In direct steam injection, high temperature steam is sprayed into a pipe or other container containing the dairy concentrate, thereby quickly sterilizing the dairy concentrate. Direct steam injection is usually performed continuously—the continuous flow of the dairy concentrate is combined with the continuous injection of steam. In direct steam injection, the dairy concentrate is sprayed into a chamber containing steam, thereby quickly and evenly sterilizing the dairy concentrate. Like direct steam injection, direct steam injection is usually performed continuously. After the heat treatment step, the sterilized dairy composition can be cooled to any suitable temperature, such as a temperature in the range of about 5°C to about 40°C or about 10°C to about 30°C.

[0051] Optionally, the disclosed method may further include the step of combining ingredients with the sterilized dairy composition. Non-limiting examples of suitable ingredients may include sugars / sweeteners, flavoring agents, preservatives (e.g., to prevent yeast or mold growth), stabilizers, emulsifiers, prebiotic substances, probiotics, vitamins, minerals, ω3 fatty acids, phytosterols, antioxidants or coloring agents, etc., and any mixture or combination thereof.

[0052] Any suitable container and condition can be used for any combination step disclosed herein, and these can be completed in batches or continuously.For example, the sterile dairy composition can be combined with a composition (or multiple compositions) to form a batch of finished dairy compositions in a suitable container (for example, tank, silo, etc.) at atmospheric pressure.As another example, the sterile composition and a composition (or multiple compositions) can be continuously combined under micropressure (for example, 5-50psig) in a pipeline or other suitable container, and the finished dairy composition can be transferred to a storage tank or loaded into a container for retail distribution and sale.Representative systems that can be used for this continuous combination, mixing and / or packaging can include tetra aldose systems and tetraflexidose systems.Other suitable methods, systems and devices for combining sterile compositions and other compositions are apparent according to the present invention.

[0053] In some embodiments of the invention, after the heat treatment step, the method may further include the step of (aseptically) packaging the sterilized dairy composition (with or without additional ingredients) in any suitable container and under any suitable conditions. Any suitable container may be used, such as a container that can be used to distribute and / or sell dairy products in retail channels. Illustrative and non-limiting examples of typical containers include cups, bottles, bags or pouches, etc. The container may be made of any suitable material, such as glass, metal, plastic, etc., and combinations thereof.

[0054] According to an embodiment of the present invention, a method for preparing a milk powder composition is disclosed, and such a method may include (or consist essentially of, or consist of): (a) subjecting a dairy product to forward osmosis to form a milk concentrate having at least about 35% by weight solids, (b) heat treating the milk concentrate to form a sterilized dairy composition, and (c) drying the sterilized dairy composition to form a milk powder composition (or a dried dairy composition). Any milk powder composition (e.g., a milk powder product) produced according to any disclosed method is within the scope of the present invention and is encompassed herein.

[0055] In these methods, the drying in step (c) may include any suitable drying technique, such as spray drying. If desired, these methods may also include a dissolution and / or agglomeration step after the drying step. Example

[0056] The present invention is further illustrated by the following examples, which are not interpreted in any way as limiting the scope of the present invention. After reading the description herein, various other aspects, embodiments, modifications and equivalents thereof may be contemplated by those of ordinary skill in the art without departing from the spirit of the present invention or the scope of the appended claims.

[0057] Total solids (wt %) are determined according to procedure SMEDP 15.10 C of a CEM Turbo solids and moisture analyzer (CEM Corporation, Matthews, North Carolina). Ash is the residue remaining after combustion to constant weight at 550° C. in a suitable apparatus; this treatment at 550° C. generally removes all organic matter, while the remaining material is primarily mineral (Standard Methods for the examination of dairy products, 17th edition (2004), American Public Health Association, Washington, D.C.). Ash testing is performed by using a Phoenix (CEM microwave oven), which heats the sample at 550° C. for 30 minutes. Ash content (also referred to herein as mineral content) is determined in wt %.

[0058] Specific Ca, Mg, Na and K contents were determined using a Perkin Elmer atomic absorption spectrophotometer. The samples were treated with trichloroacetic acid to precipitate the protein and the filtrate was analyzed by an atomic absorption spectrophotometer. Phosphorus content was determined by inductively coupled plasma spectroscopy (AOAC Official Methods of Analysis, International 8th Edition, Methods 965.17 and 985.01).

[0059] Example 1

[0060] Example 1 summarizes the experiments for producing high protein milk concentrate. High protein lactose-free skim milk was prepared by membrane filtration (ultrafiltration, nanofiltration, reverse osmosis), pasteurized at 77°C for 15 seconds, then collected in 10-L pre-sterilized plastic bags, and stored at less than 7°C before use. Table I summarizes the composition of high protein skim milk, and Table II summarizes the corresponding Ca, Mg, Na, K and P contents (in ppm by weight) in high protein skim milk. In Table I, the mineral content (in wt%) is essentially the same as the ash content (wt%), and therefore the results of the ash test are used to quantify the total mineral content in the present invention.

[0061] The high protein skim milk was subjected to forward osmosis using an Ederna Micro-Pilot apparatus (Toulouse Cedex 1, France) with an Ederna draw solution containing a high concentration of potassium lactate. The membrane used was a spirally wound cellulose triacetate membrane (Ederna, France). The operating pressure was less than 4 bar and the temperature during forward osmosis was maintained below 14°C. Table I summarizes the resulting composition of the forward osmosis (FO) concentrate of high protein skim milk and Table II summarizes the corresponding Ca, Mg, Na, K and P contents (in ppm by weight) in the FO concentrate. The high protein FO concentrate was sterilized at 142°C for 4 seconds to prepare a sterile high protein composition.

[0062] Advantageously, the protein, mineral and solid contents are significantly increased with the use of a forward osmosis step. As shown in Table I, the high protein skim milk contains 5.7 wt% protein, 0.78 wt% minerals and 9.2 wt% solids, and the FO concentrate contains 25.35 wt% protein, 3.9 wt% minerals and 39.7 wt% solids. This translates to unexpectedly high concentration factors of 4.4 on a protein basis, 5 on a mineral basis, and 4.3 on a solid basis. In addition, the corresponding mineral contents of the FO concentrate in Table II are also significantly increased: unexpectedly high concentration factors of 5.2 on a calcium basis, 5.9 on a sodium basis, and 5.3 on a potassium basis.

[0063] The solids content of the FO concentrate in Example 1 was about 40 wt%. Using the same high protein skim milk starting material, similar experiments using reverse osmosis instead of forward osmosis could only achieve about 20-22 wt% solids. Thus, unexpectedly, forward osmosis can provide 80-100% higher concentrations (much higher solids content, mineral content, protein content, etc.) than reverse osmosis.

[0064] Example 2

[0065] Example 2 summarizes the experiment of producing milk powder from forward osmosis concentrate. Forward osmosis was performed as described in Example 1. As shown in Table III, high protein lactose-free skim milk was concentrated from 9.2% solids by weight to 26.8% solids by weight (concentration factor of 2.9 based on protein, 3 based on minerals, and 2.9 based on solids) by forward osmosis process, and the FO concentrate was warmed to 40°C, stirred to obtain a uniform mixture, and then spray dried (inlet temperature of dryer 185°C; outlet temperature 85-90°C; wheel speed 25,000 rpm; feed rate 260 mL / min). Table IV summarizes the corresponding Ca, Mg, Na, K and P contents (in ppm by weight). The dried product is a free-flowing powder without lumps, off-flavors or discoloration. The color of the product is light grayish white. There were a small number of brown, charred particles at the bottom of the powder bag, which was most likely due to overheating of the milk / milk powder particles during the drying process, usually due to burn-on, friction effects in the atomizer area and rotary valve, deposits adhering to the dryer chamber walls and / or around the air distributor. The high protein, lactose-free skimmed milk powder was stored in cool and dark conditions until reconstitution. Importantly, no thermal evaporation or related techniques were used to concentrate the milk product prior to spray drying, only forward osmosis was used.

[0066] This high protein lactose-free skimmed milk powder was reconstituted by recombining with water and cream to produce high protein lactose-free milk and compared with a commercial fluid high protein milk (control). The composition was very similar.

[0067] Example 3

[0068] Example 3 summarizes an experiment to produce a concentrated skim milk product from conventional skim milk. Forward osmosis was performed as described in Example 1, except that the temperature was 45°C. Table V summarizes the composition of conventional skim milk and a high solid skim milk concentrate prepared by forward osmosis. Advantageously, the protein, mineral and solid contents are significantly increased using a forward osmosis step. As shown in Table V, skim milk contains 3.36% by weight of protein, 0.78% by weight of minerals and 9.34% by weight of solids, and the FO concentrate contains 16.1% by weight of protein, 3.59% by weight of minerals and 44.57% by weight of solids. This translates to an unexpectedly high concentration factor of 4.8 based on protein, 4.6 based on minerals, and 4.8 based on solids. The skim milk FO concentrate was sterilized at 142°C using direct UHT sterilization for 4 seconds to prepare an aseptic high solid composition. Subsequently, the high solid and high protein milk concentrate was dried to obtain a high protein milk powder.

[0069] The solids content of the FO concentrate in Example 3 was 44-45 wt%. Using the same skim milk starting material, similar experiments using reverse osmosis instead of forward osmosis could only achieve about 20-22 wt% solids. Thus, unexpectedly, forward osmosis is able to provide 100% higher concentrations (much higher solids content, mineral content, protein content, etc.) than reverse osmosis.

[0070] Construction Example 4

[0071] Example 4 was constructed to compare the amount of water that can be removed from skim milk using forward osmosis as described herein versus conventional reverse osmosis in the dairy industry. Table VI summarizes the calculations based on reverse osmosis (concentration factor of 2.55) and forward osmosis (concentration factor of 4.94). Not only is the wt % solids of forward osmosis almost twice that of reverse osmosis, but forward osmosis can remove 87 wt % of the water from skim milk, compared to only 67 wt % of the water removed by conventional reverse osmosis.

[0072] Table I. Summary of the composition of Example 1.

[0073]

[0074] Table II. Summary of mineral components of Example 1.

[0075]

[0076] Table III. Summary of Example 2 compositions.

[0077]

[0078] Table IV. Summary of mineral components of Example 2.

[0079]

[0080] Table V. Summary of Example 3 compositions.

[0081]

[0082] Table VI. Summary of Construction Example 4

[0083]

Claims

1. A method for preparing a sterile milk composition, the method comprising: (a) subjecting a dairy product to forward osmosis using a membrane system having a pore size of less than or equal to 0.001 μm to form a milk concentrate having at least 35% by weight solids; as well as (b) heat treating the milk concentrate to form the sterilized dairy composition, wherein step (a) is carried out under the following conditions: the concentration factor is at least 2 and less than or equal to 10 based on the weight % of the mineral matter.

2. The method according to claim 1, wherein the milk concentrate and the sterilized dairy composition contain: At least 37 wt % solids, at least 38 wt % solids, at least 40 wt % solids, or at least 42 wt % solids; and Less than or equal to 60 wt% solids, less than or equal to 55 wt% solids, less than or equal to 50 wt% solids, or less than or equal to 48 wt% solids.

3. The method according to claim 1 or 2, wherein step (a) is carried out under the following conditions: Pressure less than or equal to 15 psig; Pressure less than or equal to 30 psig; Pressure less than or equal to 45 psig; Pressure less than or equal to 60 psig; or Pressure less than or equal to 75 psig.

4. The method according to claim 1, wherein step (a) is carried out under the following conditions: Temperature ranges from 5 to 50°C; Temperature ranges from 10 to 40°C; Temperature ranges from 8 to 25°C; Temperature ranges from 8 to 20°C; or The temperature ranges from 5 to 15°C.

5. The method according to claim 1, wherein step (a) is carried out under the following conditions: a concentration factor of at least 2, a concentration factor of at least 3, a concentration factor of at least 3.5, a concentration factor of at least 4, a concentration factor of at least 4.5, or a concentration factor of at least 5, based on weight percent solids; and Based on weight % solids, a concentration factor less than or equal to 10, a concentration factor less than or equal to 8, a concentration factor less than or equal to 7, or a concentration factor less than or equal to 6.

6. The method according to claim 1, wherein step (a) is carried out under the following conditions: a concentration factor of at least 3, a concentration factor of at least 3.5, a concentration factor of at least 4, a concentration factor of at least 4.5, or a concentration factor of at least 5, based on weight percent mineral matter; and A concentration factor less than or equal to 8, a concentration factor less than or equal to 7, or a concentration factor less than or equal to 6, based on weight % mineral matter.

7. The method according to claim 1, wherein step (a) is carried out under the following conditions: a concentration factor of at least 2, a concentration factor of at least 3, a concentration factor of at least 3.5, a concentration factor of at least 4, a concentration factor of at least 4.5, or a concentration factor of at least 5, based on weight % protein; and Based on weight % protein, a concentration factor less than or equal to 10, a concentration factor less than or equal to 8, a concentration factor less than or equal to 7, or a concentration factor less than or equal to 6.

8. The method according to claim 1, wherein the volume of the milk concentrate is: Less than or equal to 60% by volume of the dairy product; Less than or equal to 50% by volume of the dairy product; Less than or equal to 40% by volume of the dairy product; Less than or equal to 30% by volume of the dairy product; or The volume of the dairy product is less than or equal to 25%.

9. The method of claim 1, wherein the heat treatment step comprises UHT sterilization at a temperature in the range of 135°C to 145°C for a time period in the range of 1 to 10 seconds.

10. The method of claim 1, wherein the heat treatment step comprises UHT sterilization at a temperature in the range of 148°C to 165°C for a time period in the range of 0.05 to 1 second.

11. The method of claim 1, wherein the heat treatment step comprises UHT sterilization at a temperature in the range of 150°C to 155°C for a time period in the range of 0.08 to 0.2 seconds.

12. The method of claim 1, wherein the heat treating step comprises UHT sterilization using indirect heating.

13. The method of claim 1, wherein the heat treatment step comprises UHT sterilization using direct steam injection.

14. The method of claim 1, wherein the heat treating step comprises UHT sterilization using direct steam injection.

15. The method of claim 1, wherein the heat treatment step comprises pasteurizing at a temperature in the range of 80°C to 95°C for a period of time in the range of 2 to 15 minutes.

16. The method according to claim 1, wherein the dairy product is whole milk, low-fat milk, skim milk, buttermilk, flavored milk, low-lactose milk, high-protein milk, lactose-free milk, ultrafiltered milk, microfiltered milk, or high-protein lactose-free skim milk.

17. The method of claim 1, wherein the dairy product has: 0.05 to 10% fat content by weight; or Fat content of 0.1 to 5% by weight.

18. The method of claim 1, wherein the dairy product has: 1 to 15% protein content by weight; 3 to 10% protein content by weight; 2 to 8% protein content by weight; or 3 to 6% protein content by weight.

19. The method of claim 1, wherein the dairy product has: 0.5 to 2% mineral content by weight; 0.5 to 1.5% mineral content by weight; or 0.5 to 1% mineral content by weight.

20. The method of claim 1, wherein the dairy product has: A lactose content of less than or equal to 6% by weight; A lactose content of less than or equal to 4% by weight; A lactose content of less than or equal to 1% by weight; or Lactose content less than or equal to 0.1% by weight.

21. The method of claim 1, wherein the dairy product has: 5 to 15% solids content by weight; 6 to 12% solids content by weight; 7 to 10% solids content by weight; or 8 to 10% solids content by weight.

22. The method of claim 1, wherein the dairy product contains less than or equal to 0.5 wt% fat, 2 to 8 wt% protein, 0.5 to 2 wt% minerals, and less than or equal to 6 wt% lactose.

23. The method of claim 1, wherein the dairy product contains 0.5 to 1.5 wt% fat, 2 to 8 wt% protein, 0.5 to 2 wt% minerals, and less than or equal to 6 wt% lactose.

24. The method of claim 1, wherein the dairy product contains 1.5 to 2.5 wt% fat, 2 to 8 wt% protein, 0.5 to 2 wt% minerals, and less than or equal to 6 wt% lactose.

25. The method of claim 1, wherein the dairy product contains 2.5 to 5 wt% fat, 2 to 8 wt% protein, 0.5 to 2 wt% minerals, and less than or equal to 6 wt% lactose.

26. The method of claim 1, wherein the forward osmosis step utilizes a forward osmosis draw solution comprising sodium, potassium, chloride, or a combination thereof.

27. The method of claim 1, wherein the forward osmosis step utilizes a forward osmosis draw solution comprising sucrose, glucose, galactose, lactose, fructose, maltose, or a combination thereof.

28. The method of claim 1, wherein the forward osmosis step utilizes a forward osmosis draw solution comprising potassium lactate.

29. The method of claim 1, wherein the forward osmosis step utilizes a forward osmosis draw solution comprising milk minerals.

30. The method of claim 1, wherein the forward osmosis step utilizes a forward osmosis draw solution comprising: 0.4 to 1.5% by weight of milk minerals; 0.3 to 3% by weight of milk minerals; 0.3 to 5% by weight of milk minerals; 18 to 32% by weight of milk minerals; 10 to 50% by weight of milk minerals; or 5 to 60% by weight of milk minerals.

31. The method of claim 1, wherein the forward osmosis step utilizes a forward osmosis draw solution comprising a RO retentate fraction, a UF permeate fraction, a NF permeate fraction, or a combination thereof.

32. The method of claim 1, wherein: Step (a) comprises subjecting the dairy product to forward osmosis to form the dairy concentrate and a diluted draw liquor; and The method also includes (c) removing at least a portion of the water from the diluted draw solution to form a draw solution.

33. The method of claim 32, wherein removing at least a portion of the water from the diluted draw solution comprises subjecting the diluted draw solution to reverse osmosis.

34. The method of claim 33, wherein the reverse osmosis comprises a membrane system having a pore size less than or equal to 0.001 μm.

35. The method of claim 32, wherein removing at least a portion of the water from the diluted draw solution comprises subjecting the diluted draw solution to evaporation.

36. The method of claim 35, wherein evaporating comprises a temperature greater than 50°C and a pressure less than atmospheric pressure.

37. The method of claim 1, wherein the milk concentrate and the sterilized dairy composition have: 0.05 to 10% fat content by weight; or Fat content of 0.1 to 5% by weight.

38. The method of claim 1, wherein the milk concentrate and the sterilized dairy composition have: 12 to 32% protein content by weight; 14 to 28% protein content by weight; 12 to 20% protein content by weight; or 20 to 30% protein content by weight.

39. The method of claim 1, wherein the milk concentrate and the sterilized dairy composition have: 2 to 5% mineral content by weight; 2.2 to 4.8% mineral content by weight; or 2.5 to 4.5% mineral content by weight.

40. The method of claim 1, wherein the milk concentrate and the sterilized dairy composition have: 2 to 30% carbohydrate content by weight; 5 to 15% by weight carbohydrate content; or 20 to 30% carbohydrate content by weight.

41. The method of claim 1, wherein the milk concentrate and the sterilized dairy composition have: 35 to 60% solids content by weight; 38 to 50% solids content by weight; or 40 to 55% solids content by weight.

42. The method of claim 1, wherein the milk concentrate and the sterilized dairy composition have: 800 to 2000 ppm sodium content; 5000 to 9500 ppm potassium content; 3000 to 8000 ppm calcium content; or any combination thereof.

43. The method according to claim 1, further comprising the steps of: Ingredients are combined with the sterilized dairy composition, wherein the ingredients include flavoring agents, preservatives, stabilizers, emulsifiers, prebiotic substances, probiotics, vitamins, minerals, omega 3 fatty acids, phytosterols, antioxidants, coloring agents, or any combination thereof.

44. The method of claim 43, wherein the ingredient comprises a sweetener.

45. The method of claim 43, wherein the ingredient comprises sugar.

46. ​​The method of claim 1, further comprising combining the dairy product with lactase prior to step (a) to form the dairy product having less than 0.1 wt% lactose prior to forward osmosis.

47. The method according to claim 1, further comprising the steps of: The sterilized dairy composition is packaged in a container.

48. A sterile dairy composition prepared by a method according to any one of the preceding claims.

49. A method for preparing a milk powder composition, the method comprising: The method according to any one of claims 1 to 47; as well as (c) drying the sterilized dairy composition to form the milk powder composition.

50. The method of claim 49, wherein drying comprises spray drying.

51. A dry milk powder composition prepared by the method according to claim 49 or 50.

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