Mineral enrichment agent for liquid compositions containing vegetable proteins

Abstract

The purpose of the present invention is to provide a novel technique capable of enriching mineral substances derived from a plant-derived raw material in a soluble fraction of a liquid composition containing a plant-derived protein. The mineral enrichment agent is contained in a soluble fraction of a liquid composition containing vegetable protein, and the active ingredient of the mineral enrichment agent is protein deamidase.

Description

Technical Field

[0001] This invention relates to a processing technique for enriching minerals in soluble fractions of liquid compositions containing plant proteins. Background Technology

[0002] Beverages rich in protein and other nutrients have historically been popular due to their convenient nutritional intake. In recent years, driven by factors such as the rise of vegetarianism, allergy issues, and religious reasons, plant-based milks, made from plant-based ingredients rich in plant protein, such as soybeans, oats, and almonds, have become increasingly popular as an alternative to animal milk, such as cow's milk.

[0003] On the other hand, given that the nutritional composition of plant-based milk differs from that of animal milk, products that have been fortified with calcium by adding calcium to plant-based milk are also sold.

[0004] Furthermore, techniques for nutritional fortification in foods prepared from plant-based ingredients have been reported. For example, Patent Document 1 describes a method for fortifying whole grains and foods rich in dietary fiber while maintaining a low calorie intake, comprising a hydrolyzed whole grain composition and a composition that does not exhibit hydrolytic activity towards dietary fiber in its active state. α - Nutritional products containing amylase or its fragments are formulated with at least two essential minerals and at least four essential vitamins. Additionally, Non-Patent Literature 1 reports a technique for reducing phytic acid levels in food by applying phytase during food processing, and Non-Patent Literature 2 describes the application of this technique to soybean protein isolates, soy milk, pea flour, bread dough, and grains.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Publication No. 2013-513368 Non-patent literature Non-patent literature 1: Biotechnol. Adv. (1991) 122:145-161 Non-patent literature 2: Int.J. Food Sci. Technol. (2002) 37:823-833 Summary of the Invention

[0006] The technical problem that the invention aims to solve The technology described in Patent Document 1 adds minerals from the outside, thus failing to effectively utilize the minerals naturally present in the food ingredients. While the technologies described in Non-Patent Documents 1 and 2 can effectively utilize the minerals naturally present in the food ingredients, they are limited in that the degree to which minerals can be solubilized depends on the amount of phytic acid contained in the food ingredients.

[0007] Therefore, the object of the present invention is to provide a new technology that can enrich minerals derived from plant-based raw materials in the soluble fraction of a liquid composition containing plant-based proteins.

[0008] Technical solutions for solving technical problems The inventors conducted in-depth research and discovered that by treating a liquid composition containing plant-based proteins with a protein deamidase, minerals derived from plant-based ingredients can be enriched in the soluble fraction of the resulting food or beverage containing plant-based proteins. This invention was completed based on further repeated research following this insight.

[0009] That is, the present invention provides an invention in the manner described below.

[0010] Item 1. A mineral enrichment agent for a liquid composition containing plant proteins, which enriches minerals in the soluble fraction of the liquid composition containing plant proteins, said mineral enrichment agent comprising a protein deamidase.

[0011] Item 2. A mineral enriching agent for a liquid composition containing plant-based proteins according to Item 1, wherein the mineral enriching agent is used to increase the amount of soluble minerals.

[0012] Item 3. A mineral enriching agent for a liquid composition containing plant-based proteins according to Item 1 or 2, wherein the mineral enriching agent is used to improve the binding of minerals to soluble proteins.

[0013] Item 4. A mineral enriching agent for a liquid composition containing plant-based protein according to any one of items 1 to 3, wherein the mineral is selected from zinc, iron, calcium, and magnesium.

[0014] Item 5. A mineral enrichment agent for a liquid composition containing plant-based protein according to any one of items 1 to 4, wherein the protein deamidase is a protein glutaminase.

[0015] Item 6. A mineral enrichment agent for a liquid composition containing plant protein according to any one of items 1 to 5, wherein the plant protein is a protein selected from plants of the legume, cereal and seed classes.

[0016] Item 7. A method for enriching minerals in a soluble fraction of a liquid composition containing plant protein, comprising the step of acting a protein deamidase on the liquid composition containing plant protein.

[0017] Item 8. A method for increasing the amount of soluble minerals in a liquid composition containing plant protein, comprising the step of acting a protein deamidase on the liquid composition containing plant protein.

[0018] Item 9. A method for improving the binding affinity of minerals to soluble proteins in a liquid composition containing plant proteins, comprising the step of acting a protein deamidase on the liquid composition containing plant proteins.

[0019] Invention Effects According to the present invention, minerals derived from plant-based raw materials can be enriched in the soluble fraction of a liquid composition containing plant-based proteins. Detailed Implementation

[0020] 1. A mineral enrichment agent for liquid compositions containing plant-based proteins. The mineral enrichment agent of the liquid composition containing plant protein of the present invention is characterized by containing a protein deamidase for enriching minerals in the soluble fraction of the liquid composition containing plant protein.

[0021] 1-1. Applications The present invention relates to the use of a mineral enriching agent (hereinafter also referred to as "mineral enriching agent") of a liquid composition containing plant proteins for enriching minerals in the soluble fraction of the composition. Soluble fraction refers to water-soluble fraction.

[0022] As one example of an implementation of the use of enriching minerals in soluble fractions (hereinafter also referred to as "first use"), an application that increases the amount of soluble minerals can be cited. Soluble minerals refer to water-soluble minerals. As specific forms of soluble minerals, minerals bound to free minerals and soluble proteins can be cited. Soluble minerals can take the form of at least one of these forms (i.e., any one or two).

[0023] Another example of an implementation method for enriching minerals in soluble fractions (hereinafter also referred to as "secondary use") is the use of improving the binding affinity of minerals to soluble proteins. Soluble proteins refer to water-soluble proteins.

[0024] The minerals targeted for enrichment are not particularly limited, but zinc, iron, calcium, and / or magnesium are preferably included. In the first use, among zinc, iron, calcium, and magnesium, zinc, iron, and / or calcium are more preferably included as the minerals targeted for enrichment, zinc and / or iron are even more preferably included, and zinc and iron are still more preferably included. In the second use, among zinc, iron, calcium, and magnesium, zinc, iron, and / or calcium are more preferably included as the minerals targeted for enrichment, and zinc, iron, and calcium are still more preferably included.

[0025] Mineral enrichment in soluble fractions can be confirmed by the increased amount of minerals in any form present in the soluble fraction compared to the case without the use of protein deamidases (i.e., the case of treating a liquid composition containing plant proteins under the same conditions except without the use of protein deamidases).

[0026] In the first use of the mineral enrichment agent of the present invention, the increase in the amount of soluble minerals can be confirmed by the following: compared with the case where protein deamidase is not used (i.e., the case where a liquid composition containing plant protein is treated under the same conditions except for the absence of protein deamidase), the amount of minerals present in the soluble fraction (specifically, the total amount of free minerals and minerals bound to soluble proteins) increases.

[0027] In a second use of the mineral enrichment agent of the present invention, the increased binding affinity of minerals to soluble proteins can be confirmed by the following: the amount of minerals present in the soluble protein fraction (specifically, the amount of minerals bound to the soluble proteins) increases compared to the case where protein deamidase is not used (i.e., the case where a liquid composition containing plant proteins is treated under the same conditions except for the absence of protein deamidase).

[0028] The mineral enrichment agent of the present invention, the liquid composition containing plant protein that is the object of application, and the specific method of use are described in detail in "2. Method for enriching minerals in the soluble fraction of the liquid composition containing plant protein, method for increasing the amount of soluble minerals in the liquid composition containing plant protein, and method for improving the binding affinity between minerals and soluble proteins in the liquid composition containing plant protein".

[0029] 1-2. Protein deamidases Protein deamidases are the active ingredients of the mineral enrichment agent of the present invention, which contribute to mineral enrichment (more specifically, an increase in the amount of soluble minerals or an improvement in the binding affinity between minerals and soluble proteins). As for protein deamidases, there are no particular limitations on their type or source, as long as they exhibit the function of decomposing the amide-containing side chains of proteins without accompanying peptide bond cleavage or protein cross-linking. Examples of protein deamidases include those disclosed in Japanese Patent Application Publication No. 2000-50887, Japanese Patent Application Publication No. 2001-218590, and International Patent Publication No. 2006 / 075772, which are derived from the genera *Chryseobacterium*, *Flavobacterium*, *Empedobacter*, *Sphingobacterium*, *Aureobacterium*, or *Myroides*. These protein deamidases can be used alone or in combination.

[0030] Examples of protein deamidases include protein glutaminase (EC3.5.1.44) and protein asparaginase, and more broadly, protein arginine deiminase. Among these protein deamidases, protein glutaminase is preferred from the viewpoint of further enhancing mineral enrichment.

[0031] Among these protein deamidases, from the viewpoint of further improving the mineral enrichment effect, protein deamidases derived from the genus *Chlorella* are more preferably cited, protein glutaminases derived from the genus *Chlorella* are more preferably cited, and protein glutaminases derived from the species *Chlorella utilis* are even more preferably cited.

[0032] Protein deamidases can be prepared from the culture medium of microorganisms that serve as the source of the aforementioned protein deamidases. Specific preparation methods include recovering protein deamidases from the culture medium or bacterial cells of these microorganisms. For example, when using protein deamidase-secreting microorganisms, the bacterial cells can be recovered from the culture medium beforehand by filtration, centrifugation, etc., and the enzyme can then be separated and / or purified. Alternatively, when using non-secreting protein deamidase microorganisms, the bacterial cells can be recovered from the culture medium beforehand, and the enzyme can be exposed by pressure treatment, ultrasonic treatment, etc., after breaking down the bacterial cells, and then separated and / or purified. Known protein separation and / or purification methods can be used without particular limitation, such as centrifugation, UF concentration, salting out, and various chromatographic methods using ion exchange resins. The separated and / or purified enzyme can be powdered by freeze-drying, vacuum drying, or other drying methods. Alternatively, appropriate excipients and / or drying aids can be used in these drying methods to achieve powdering. Alternatively, the isolated and / or purified enzyme can be a liquefied enzyme obtained by adding appropriate additives and then filtration sterilization. Furthermore, commercially available products can also be used as protein deamidases.

[0033] The amount of protein deamidase contained in the mineral enrichment agent of the present invention is not particularly limited as long as the effect based on protein deamidase can be effectively obtained when using the mineral enrichment agent of the present invention. For example, 0.1 to 5000 U / g can be listed.

[0034] It should be noted that, regarding the activity of protein deamidases, using benzyloxycarbonyl-L-glutamine glycine (Z-Gln-Gly) as a substrate will release 1 [unit of protein] within 1 minute. μ The amount of enzyme in mol of ammonia is taken as 1 unit (1U).

[0035] 1-3. Other ingredients In the mineral enrichment agent of the present invention, as components other than protein deamidase, it may contain formulation-acceptable additives and / or bases for enzyme preparations, or it may not contain formulation-acceptable additives and / or bases for enzyme preparations. Examples of such additives and bases include excipients, drying aids, buffers, antioxidants, UV stabilizers, preservatives, pH adjusters, dispersants, emulsifiers, solubilizers, carriers, and solvents (water, etc.). These additives and bases may be used individually or in combination of two or more. Furthermore, the content of these additives and bases can be appropriately set according to the type of these components and / or the formulation form.

[0036] The mineral enrichment agent of the present invention, as a component other than protein deamidase, may or may not contain other enzymes. Preferably, the mineral enrichment agent of the present invention does not contain phytase.

[0037] 1-4. Characteristics There are no particular limitations on the properties of the mineral enriching agent of the present invention, for example, dry preparations and liquid preparations in the form of powder, fine granules, or granules can be mentioned.

[0038] 2. A method for enriching minerals in the soluble fraction of a liquid composition containing plant-based proteins; Methods for increasing the amount of soluble minerals in liquid compositions of plant-based proteins, and liquid compositions containing plant-based proteins. Methods to improve the binding affinity of minerals in compounds to soluble proteins As described above, protein deamidases facilitate the enrichment of minerals in liquid compositions containing plant proteins (more specifically, an increase in the amount of soluble minerals or an improvement in the binding affinity of minerals to soluble proteins). Therefore, the present invention also provides a method for enriching minerals in the soluble fraction of a liquid composition containing plant proteins, including the step of acting a protein deamidase on the liquid composition containing plant proteins (more specifically, a method for increasing the amount of soluble minerals in a liquid composition containing plant proteins, including the step of acting a protein deamidase on the liquid composition containing plant proteins; and a method for improving the binding affinity of minerals to soluble proteins in a liquid composition containing plant proteins, including the step of acting a protein deamidase on the liquid composition containing plant proteins).

[0039] In the mineral enrichment method of the present invention, the terms "soluble fraction", "mineral enrichment", "increased amount of soluble minerals", "increased binding to soluble proteins", "minerals", "protein deamidase", etc., are as detailed in "1. Mineral enriching agent of liquid composition containing plant protein" above.

[0040] 2-1. A process for subjecting a protein deamidase to a liquid composition containing plant-based proteins. In the process of causing a protein deamidase to act on a liquid composition containing plant protein, a mixture of plant protein containing a liquid composition containing plant protein and a protein deamidase is appropriately prepared and subjected to a treatment that allows the enzyme reaction to proceed.

[0041] 2-1-1. A liquid composition containing plant-based proteins The application of the mineral enrichment agent of the liquid composition containing plant protein of the present invention is not particularly limited to any liquid composition containing plant protein and minerals and containing water.

[0042] 2-1-1-1. Specific forms of liquid compositions containing plant proteins Specific forms of liquid compositions containing plant-based proteins include: (i) a liquid obtained by using dried powder of plant-based raw materials (i.e., organs or parts of the plant from which the plant-based protein is derived) as the plant-based protein material, dispersing the plant-based protein material or its aqueous extract in water, and then, as needed, removing water-insoluble matter derived from the plant-based raw materials by any means such as centrifugal filtration, filtration, filter bags, or sieves; (ii) a liquid obtained by using the plant-based raw material itself or its dried product as the plant-based protein material, breaking down and dispersing the plant-based protein material or its aqueous extract in water, and then, as needed, removing water-insoluble matter derived from the plant-based raw materials by any means such as centrifugal filtration, filtration, filter bags, or sieves; (iii) A liquid obtained by removing water-insoluble matter derived from plant-based raw materials by any means such as centrifugal filtration, filtration, filter bags, or sieves; (iv) A liquid obtained by increasing the content of plant protein by removing at least a portion of the components other than plant protein from the liquid of (i) or (ii) above (which also contains minerals derived from plant-based raw materials); (v) A liquid obtained by using a dried powder prepared from any of the liquids of (i) to (iii) above as a plant protein material, and by dissolving and / or dispersing the plant protein material or its aqueous extract in water.

[0043] Preferred examples of liquid compositions containing plant-based proteins include: (i) liquid obtained by dispersing dried powder of plant-based protein materials or their aqueous extracts in water; (ii) liquid obtained by breaking down and dispersing the plant-based protein materials themselves or their aqueous extracts in water; and (iv) liquid corresponding to the preferred liquids (i) and (ii). A preferred specific example of a liquid composition containing plant-based proteins is plant-based milk.

[0044] 2-1-1-2. Plant-based protein As a plant-based protein, there are no particular restrictions as long as it is derived from any raw material containing plant protein and minerals (plant-based raw materials). Plant-based raw materials that can serve as sources of plant-based protein include, for example: legumes such as soybeans, peas, lentils, chickpeas, black beans, broad beans, mung beans, lupins, and kidney beans; cereals such as wheat, barley, oats, sorghum, rice, rye, buckwheat, barnyard millet, foxtail millet, teff, corn, and potatoes; and seeds such as almonds, coconuts, peanuts, cashews, hazelnuts, pecans, macadamia nuts, pistachios, walnuts, Brazil nuts, pili nuts, chestnuts, sesame seeds, pine nuts, hemp seeds (referring to so-called industrial hemp, specifically varieties that do not contain THC (tetrahydrocannabinol), which causes sensory alterations, or have low THC concentrations. Industrial hemp, because it does not contain THC or has low concentrations, is not effective as a sensory altering agent and will not lead to abuse.), chia seeds, quinoa, amaranth seeds, canary grass seeds, and flax seeds.

[0045] In this invention, the plant protein can be derived from a single plant material or from a combination of two or more of the above-mentioned plant materials.

[0046] From the perspective of further enhancing mineral enrichment, the plant-based proteins mentioned above are preferably derived from legumes, cereals, and seeds, and more preferably from soybeans, peas, lentils, chickpeas, broad beans, mung beans, wheat, barley, sorghum, rice, rye, corn, almonds, coconuts, peanuts, cashews, hazelnuts, pistachios, walnuts, and hemp seeds (industrial hemp).

[0047] From the viewpoint of further increasing the amount of soluble minerals, the plant-based proteins mentioned above are preferably legumes, cereals, and seeds, and more preferably plant-based proteins derived from soybeans, peas, lentils, chickpeas, broad beans, mung beans, wheat, barley, sorghum, rice, rye, corn, almonds, coconuts, peanuts, hazelnuts, pistachios, walnuts, and hemp seeds (industrial hemp).

[0048] Among the aforementioned plant-based proteins, from the viewpoint of further improving the binding effect of minerals and soluble proteins, legumes and seeds are preferred examples, and more preferably, plant-based proteins derived from soybeans, peas, lentils, chickpeas, broad beans, coconuts, peanuts, cashews, hazelnuts, and pistachios are preferred examples.

[0049] As a plant-based protein material, the plant-based raw material itself, the dried product of the plant-based raw material, the dried powder of the plant-based raw material, or materials that have been processed to remove at least a portion of the components other than plant-based protein, thereby increasing the content of plant-based protein (including minerals derived from the plant-based raw material), can be used.

[0050] The content of plant-based protein in plant-based protein materials can be, for example, 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 0.5% by weight or more, 1% by weight or more, or 3% by weight or more, further preferably 5% by weight or more, even more preferably 6% by weight or more, 7% by weight or more, 8% by weight or more, 9% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, or 30% by weight or more. There is no particular limitation on the upper limit of this content range; for example, it can be 95% by weight or less, or 90% by weight or less, preferably 80% by weight or less, 70% by weight or less, or 60% by weight or less, more preferably 55% by weight or less, 50% by weight or less, or 45% by weight or less, further preferably 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, or 10% by weight or less.

[0051] The content of plant protein material in the liquid composition containing plant protein can be, for example, 0.1 to 50% by weight, 0.5 to 40% by weight, or 1 to 30% by weight, preferably 2 to 25% by weight or 2.5 to 20% by weight, more preferably 5 to 15% by weight, and even more preferably 8 to 12% by weight.

[0052] The content of plant-based protein in the liquid composition containing plant-based protein is, for example, 0.001% by weight or more, preferably 0.01% by weight or more, more preferably 0.05% by weight or more, 0.1% by weight or more, or 0.3% by weight or more, further preferably 0.5% by weight or more, even more preferably 0.6% by weight or more, 0.7% by weight or more, 0.8% by weight or more, 0.9% by weight or more, 1% by weight or more, 2% by weight or more, or 3% by weight or more. There is no particular limitation on the upper limit of this content range; for example, 9.5% by weight or less, or 9% by weight or less, preferably 8% by weight or less, 7% by weight or less, or 6% by weight or less, more preferably 5.5% by weight or less, 5% by weight or less, or 4.5% by weight or less, further preferably 4% by weight or less, 3.5% by weight or less, 3% by weight or less, 2.5% by weight or less, 2% by weight or less, 1.5% by weight or less, or 1% by weight or less.

[0053] 2-1-1-3. Other ingredients In a liquid composition containing plant-based proteins, in addition to plant-based proteins and minerals derived from plant-based raw materials, other components may include one or more arbitrary components, or may not include any arbitrary components. Examples of other components include components other than proteins and minerals derived from plant-based raw materials, other food ingredients, and food additives. Examples of food additives include thickeners, binders, flavorings, pH adjusters, buffers, colorings, and fragrances.

[0054] 2-1-2. Dosage of protein deamidase As a protein deamidase, the protein deamidase described in "1-2. Protein Deamidase" above is used.

[0055] The amount of protein deamidase used relative to the liquid composition containing plant-based proteins can be appropriately determined by those skilled in the art based on the degree of mineral enrichment effect targeted.

[0056] For example, the amount of protein deamidase used as the amount of plant protein contained in each 1g of liquid composition containing plant protein can be 0.005U or more, or 0.01U or more, preferably 0.05U or more, or 0.1U or more, more preferably 0.5U or more, further preferably 1U or more, even more preferably 2U or more, or 3U or more. There is no particular limitation on the upper limit of this usage range; for example, it can be 5000U or less, or 1000U or less, preferably 500U or less, or 100U or less, more preferably 50U or less, or 25U or less, further preferably 20U or less, 15U or less, or 10U or less, even more preferably 7U or less.

[0057] Furthermore, the amount of protein deamidase used as the plant protein material contained in each 1g of the liquid composition containing plant protein is, for example, 0.0005U or more, preferably 0.005U or more, more preferably 0.025U or more, 0.05U or more, or 0.15U or more, further preferably 0.25U or more, and even more preferably 0.3U or more, 0.35U or more, 0.4U or more, 0.45U or more, 0.5U or more, 1U or more, or 1.5U or more. There is no particular limitation on the upper limit of this usage range; for example, 4.7U or less, or 4.5U or less, preferably 4U or less, 3.5U or less, or 3U or less, more preferably 2.7U or less, 2.5U or less, or 2.3U or less, and even more preferably 2U or less, 1.7U or less, 1.5U or less, 1.2U or less, 1U or less, 0.7U or less, or 0.5U or less.

[0058] 2-1-3. Processing Conditions The plant-based protein mixture provides the processing conditions for the enzymatic reaction of mineral enrichment. These conditions can be appropriately determined by those skilled in the art through preliminary experiments, based on the optimal temperature and pH of the protein deamidase used, and the degree of mineral enrichment desired.

[0059] Specifically, the temperature condition can be determined based on the optimal temperature of the protein deamidase used, for example, 20–70°C, preferably 40–60°C, more preferably 45–55°C, and even more preferably 47–53°C. The pH condition can be determined based on the optimal pH of the protein deamidase used, for example, at 25°C, a pH of 4–9, preferably 5–8, and more preferably 6–8. The time condition can be determined based on the reaction scale, for example, 1–48 hours, preferably 1–24 hours, more preferably 8–20 hours, or 10–18 hours.

[0060] 2-2. Other processes The mineral enrichment method for the liquid composition containing plant protein of the present invention may include steps other than the step of acting the protein deamidase, or may not include other steps. Examples of other steps include the step of preparing the liquid composition containing plant protein, the enzyme inactivation step, the filtration step, the concentration step, and the drying step. These other steps may be performed individually or in combination of two or more steps.

[0061] The process for preparing a liquid composition containing plant protein is specifically described in the method for obtaining the liquid described in (i) to (iv) of “2-1-1-1. Specific form of liquid composition containing plant protein” above.

[0062] In the enzyme inactivation process, any method can be used to deactivate the enzyme based on the optimal temperature and pH of the protein deamidase used, with thermal inactivation being preferred. Specific conditions for thermal inactivation include, for example, heating at 90°C to boiling temperature, preferably 95°C to boiling temperature, and more specifically, heating at 95°C to 100°C for 5 to 15 minutes, preferably 7 to 12 minutes.

[0063] In the filtration process, any method can be used to separate the water-insoluble fraction from the water-soluble fraction. Specific examples of this method include centrifugation and pressure filtration.

[0064] In the concentration process, any method can be used to remove at least a portion of the components of the liquid being treated to obtain a concentrate of the liquid or other fluid. Specific examples of this method include concentration methods utilizing water removal, and methods for separating low molecular weight fractions from soluble protein fractions (e.g., ultrafiltration). In the method of the present invention, according to the method corresponding to the second application, minerals can be bound to soluble proteins. Therefore, even when concentrating soluble proteins by using a method for separating low molecular weight fractions and soluble protein fractions as another step, the outflow of minerals into the low molecular weight fraction can be reduced.

[0065] In the drying process, any drying method can be used. Specific examples of such methods include freeze drying, vacuum drying, and spray drying.

[0066] 2-3. Products Depending on the selection of other processes, the processed composition containing plant-based proteins obtained by the method of the present invention can be a liquid or other fluid, or a dried product. In the presence of water, the minerals in the soluble fraction of the processed composition containing plant-based proteins obtained by the method of the present invention are enriched.

[0067] The plant-based protein-containing composition processed by the method of the present invention can, for example, be applied to plant-based dairy products. Examples of plant-based dairy products include, for example, plant-based milk and plant-based butter (including their dried forms), and plant-based fermented milk products (e.g., plant-based cheese, plant-based yogurt, etc.).

[0068] Example The present invention will be specifically described below with examples, but the present invention is not to be construed as being limited to the following examples.

[0069] [A. Plant-based protein material] Use the plant-based protein materials shown in Table 1. It should be noted that, among the plant-based materials listed below, hemp protein materials do not contain THC (tetrahydrocannabinol).

[0070] [Table 1]

[0071] [B. Protein deamidase] As a protein deamidase, a protein glutaminase derived from Chryseobacterium proteolyticum (manufactured by Amano Enzyme Products Co., Ltd.) is used. Hereinafter, this protein deamidase will also be referred to as "PG".

[0072] Protein deamidase activity was determined by the following method.

[0073] Add 0.1 mL of the sample solution containing protein deamidase to 1 mL of 0.2 M phosphate buffer (pH 6.5) containing 30 mM Z-Gln-Gly, incubate at 37°C for 10 minutes, then add 1 mL of 0.4 M TCA solution to stop the reaction. As a blank, add 1 mL of 0.4 M TCA solution to 1 mL of 0.2 M phosphate buffer (pH 6.5) containing 30 mM Z-Gln-Gly, then add 0.1 mL of the sample solution containing protein deamidase, and incubate at 37°C for 10 minutes.

[0074] For the solution obtained above, use (Fujifilm and Wako Pure Chemical Industries, Ltd.) The amount of ammonia generated in the reaction solution was determined. The ammonia concentration in the reaction solution was determined by using a standard curve showing the relationship between ammonia concentration and absorbance (630 nm) prepared using an ammonia standard solution (ammonium chloride).

[0075] 1 will be generated within 1 minute μ The enzyme activity of protein deamidase is calculated using the following mathematical formula, where mol of ammonia is taken as 1 unit (1U). In the formula, the reaction solution volume is 2.1, the enzyme solution volume is 0.1, and Df is the dilution factor of the enzyme solution. Additionally, 17.03 is the molecular weight of ammonia.

[0076] [Number 1] Protein deamidase activity (U / mL) =Ammonia concentration in reaction solution (mg / L) × (1 / 17.03) × (reaction solution volume / enzyme solution volume) × (1 / 10) × Df [C. Preparation of liquid compositions containing plant-based proteins by mineral enrichment processing] 40g of each of the plant protein materials described in "A. Plant Protein Material" above were added to 360mL of water and soaked overnight to soften the plant protein materials. Then, the entire mixture containing the plant protein materials and water was added to a stirrer to break down the plant protein materials, thereby obtaining a liquid composition containing plant protein. PG was added to the liquid composition containing plant protein at a concentration of 5.0U per 1g of plant protein, and the mixture was reacted overnight at 50°C. After the enzyme reaction, the mixture was treated in a boiling water bath for 10 minutes to thermally inactivate it.

[0077] [C1. Used to evaluate samples with increased soluble mineral content] After heat inactivation, the solid components (water-insoluble fraction) are removed by centrifugation (15000 rpm, 5 minutes) to obtain a processed liquid composition containing plant protein (hereinafter referred to as "PG-treated plant milk"). Alternatively, the same operation is performed on the liquid composition containing plant protein without adding PG to obtain a processed liquid composition containing plant protein without PG treatment (hereinafter referred to as "PG-untreated plant milk").

[0078] [C2. Samples used to evaluate increased binding to soluble proteins] The obtained PG-treated plant-based milk and PG-untreated plant-based milk were concentrated 10-fold using a 3000 NMWL centrifugal ultrafiltration filter. This yielded a fraction of soluble protein that was concentrated (hereinafter referred to as "soluble protein fraction") and a low molecular weight fraction that passed through the filter (hereinafter referred to as "low molecular weight fraction").

[0079] [D. Mineral enrichment evaluation] For the obtained PG-treated plant-based milk, the enrichment of zinc, iron, calcium, and / or magnesium was evaluated using the following mineral assay kit.

[0080] [Table 2]

[0081] [D1. Evaluation of increased soluble mineral content] The mineral content of PG-treated and untreated plant-based milk obtained in “C1. Samples for evaluating increased soluble mineral content” above was determined. Based on the measured values, the rate of increase in soluble mineral content was calculated using the following mathematical formula. A larger value indicates a greater increase in soluble mineral content (an increase in the amount of minerals present in the soluble fraction compared to the case without PG), thus indicating mineral enrichment in the soluble fraction of the liquid composition containing plant proteins. The results are shown in Table 3.

[0082] [Number 2]

[0083] [Table 3]

[0084] As shown in Table 3, the amount of soluble minerals increased after PG treatment, thus confirming the mineral enrichment of plant-based milk.

[0085] Specifically, zinc enrichment (increased soluble zinc content) was confirmed in plant-based milks from wheat, corn, sorghum, barley, rice, rye, lentils, soybeans, mung beans, chickpeas, broad beans, peas, peanuts, pistachios, hemp seeds, walnuts, and hazelnuts, with particularly significant enrichment (increased soluble zinc content) in plant-based milks from wheat, corn, and broad beans.

[0086] Iron enrichment (increased soluble iron content) was confirmed in plant-based milks from wheat, corn, sorghum, barley, lentils, soybeans, mung beans, chickpeas, broad beans, peas, peanuts, pistachios, coconuts, and almonds. Iron enrichment (increased soluble iron content) was particularly significant in plant-based milks from wheat, corn, sorghum, lentils, and chickpeas.

[0087] Calcium enrichment (increased soluble calcium content) was confirmed in plant-based milks made from rye, lentils, soybeans, peanuts, and pistachios. Magnesium enrichment (increased soluble magnesium content) was confirmed in plant-based milks made from rye and peanuts.

[0088] In addition, all four minerals were found to be enriched in peanut milk (with an increased amount of soluble minerals).

[0089] [D2. Evaluation of improved binding to soluble proteins] The mineral content of the soluble protein fraction and the low molecular weight fraction obtained in “C2. Samples for evaluating improved binding to soluble proteins” above was determined. Based on the measured values, the binding rate to soluble proteins was calculated using the following mathematical formula.

[0090] [Number 3]

[0091] Using the obtained binding rate with soluble proteins, the enhancement rate of binding with soluble proteins was calculated using the following mathematical formula. A higher value indicates a greater degree of binding between the mineral and the soluble protein (an increase in the amount of mineral present in the soluble protein fraction compared to the case without PG), thus indicating mineral enrichment in the soluble fraction of the liquid composition containing plant proteins. The results are shown in Table 4.

[0092] [Number 4]

[0093] [Table 4]

[0094] As shown in Table 4, PG treatment improved the binding of soluble proteins, thus confirming the mineral enrichment of plant-based milk.

[0095] Specifically, zinc, iron, and calcium were enriched in plant-based milks made from grains and seeds such as lentils, soybeans, chickpeas, broad beans, peas, peanuts, pistachios, hazelnuts, coconuts, and cashews (with increased binding to soluble proteins); zinc, iron, calcium, and magnesium were enriched in plant-based milks made from lentils, peas, pistachios, hazelnuts, and cashews (with increased binding to soluble proteins).

[0096] In particular, zinc was significantly enriched (with increased binding to soluble proteins) in plant-based milk from soybeans, chickpeas, peas, and cashews; iron was significantly enriched (with increased binding to soluble proteins) in plant-based milk from peas, peanuts, and cashews; calcium was significantly enriched (with increased binding to soluble proteins) in plant-based milk from peas, peanuts, hazelnuts, and cashews; and magnesium was significantly enriched (with increased binding to soluble proteins) in plant-based milk from pistachios.

[0097] In addition, all four minerals were found to be enriched in plant-based milks made from lentils, peas, pistachios, hazelnuts, and cashews (with increased binding to soluble proteins).

Claims

1. A mineral enrichment agent comprising a liquid composition containing plant-based proteins, characterized in that, Minerals in the soluble fraction of the liquid composition containing plant-based proteins are enriched, wherein the mineral enriching agent comprises a protein deamidase.

2. The mineral enrichment agent of the liquid composition containing plant protein according to claim 1, wherein, The mineral enrichment agent is used to increase the amount of soluble minerals.

3. The mineral enrichment agent of the liquid composition containing plant protein according to claim 1, wherein, The mineral enrichment agent is used to improve the binding affinity between minerals and soluble proteins.

4. The mineral enriching agent of the liquid composition containing plant protein according to claim 1, wherein, The minerals are selected from zinc, iron, calcium, and magnesium.

5. The mineral enrichment agent of the liquid composition containing plant protein according to claim 1, wherein, The protein deamidase is a protein glutaminase.

6. The mineral enrichment agent of the liquid composition containing plant protein according to claim 1, wherein, The plant protein is selected from plants of the legume, cereal and seed categories.

7. A method for enriching minerals in a soluble fraction of a liquid composition containing plant-based proteins, characterized in that, The process includes the step of applying a protein deamidase to a liquid composition containing plant-based proteins.

8. A method for increasing the amount of soluble minerals in a liquid composition containing plant-based proteins, characterized in that, The process includes the step of applying a protein deamidase to a liquid composition containing plant-based proteins.

9. A method for improving the binding affinity of minerals to soluble proteins in a liquid composition containing plant-based proteins, characterized in that, The process includes the step of applying a protein deamidase to a liquid composition containing plant-based proteins.

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