Hardness improver for plant-based milk coagulation foods and method for producing plant-based milk coagulation foods

Abstract

The present invention provides a hardness enhancer for plant-based milk coagulated foods that can improve the hardness of such foods without substantially impairing their flavor, and a method for producing plant-based milk coagulated foods that have higher hardness and a good flavor. [Solution] A hardness enhancer for vegetable milk coagulation foods, comprising oils and fats with a solid fat content of 4% by mass or more at 20°C, and a diglycerin fatty acid ester, wherein the content of the diglycerin fatty acid ester is 0.4 to 3.5% by mass, and the total amount of emulsifier is 5.0% by mass or less.

Description

[Technical Field]

[0001] This invention relates to a hardness enhancer for plant-based milk coagulated foods and a method for producing plant-based milk coagulated foods. [Background technology]

[0002] Because plant-based milk does not contain lactose, it can be consumed by people with lactose intolerance who cannot consume animal-based milk, and many beverages and processed foods using plant-based milk are known. For example, tofu, a soy milk coagulation product, is attracting worldwide attention as a health food containing high-quality plant-based protein. To make processed foods using plant-based milk more easily accessible, a wide variety of products have been developed. For example, Patent Document 1 discloses a method for producing high-calorie tofu that allows for efficient calorie intake with small meal portions, while also improving taste and shelf life by adding the unique functionality of medium-chain fatty acids. Furthermore, the "Tofu Bar" developed by Asahiko Co., Ltd. contains 10g of plant-based protein per bar, making it easy to consume protein while keeping the overall calorie count low. In addition, "Tofu Bars" are being manufactured in various flavors, such as umami kelp and basil salt. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-38575 [Overview of the project] [Problems that the invention aims to solve]

[0004] Plant-based milk curds are generally soft, and chewy varieties are not well known. For example, if the hardness of a food can be controlled to match various flavors, it would be possible to create new flavors of plant-based milk curds, broadening the scope of product development and leading to the expansion of the plant-based milk market. However, it is known that when the hardness of plant-based milk curds (e.g., tofu) is increased using conventional methods (e.g., dehydration by pressing), the leaching of soluble flavor components such as sugars results in a bland taste.

[0005] The present invention aims to provide a hardness enhancer for plant-based milk coagulated foods that can improve the hardness of such foods without substantially impairing their flavor. Furthermore, the present invention aims to provide a method for producing plant-based milk coagulated foods that have higher hardness and a better flavor. [Means for solving the problem]

[0006] In view of the above problems, the inventors conducted extensive research. As a result, they found that when mixing oils with a solid fat content of a certain amount or more with vegetable milk, by reducing the total amount of emulsifier used, using a specific amount of diglycerin fatty acid ester, or increasing the shear force of the mixture, an emulsified dispersion containing fine oil droplets can be prepared, and by coagulating this emulsified dispersion, the hardness of the resulting coagulated vegetable milk food can be increased. Furthermore, they found that the food is less likely to have off-flavors derived from emulsifiers and has superior flavor. The present invention was completed based on these findings and further research. [Effects of the Invention]

[0007] The hardness enhancer for plant-based milk coagulated foods of the present invention, when mixed with plant-based milk, can create an emulsified dispersion with finer oil droplets even under relatively weak shear force. By coagulating this emulsified dispersion, the resulting plant-based milk coagulated food can have higher hardness and better flavor. Furthermore, according to the method for producing plant-based milk coagulated food of the present invention, it is possible to obtain plant-based milk coagulated food with higher hardness and better flavor. [Modes for carrying out the invention]

[0008] Preferred embodiments of the present invention will be described in detail, but the present invention is not limited to the following forms other than those specified herein.

[0009] In one embodiment, the present invention provides a hardness enhancer for vegetable milk coagulated foods (the present invention's hardness enhancer for vegetable milk coagulated foods) containing an oil having a certain amount or more of solid fat content and a specific amount of diglycerin fatty acid ester to emulsify and disperse the oil in vegetable milk in the form of fine particles, and a method for producing a vegetable milk coagulated food using the said agent (First Embodiment). In another embodiment of the present invention, the present invention provides a method for producing a vegetable milk coagulated food that includes a step of emulsifying and dispersing an oil having a certain amount or more of solid fat content in vegetable milk with high shear force to obtain a pre-emulsified liquid with small oil droplets, without requiring the use of a specific amount of diglycerin fatty acid ester as an emulsifier (Second Embodiment). In either embodiment, the total amount of emulsifier used is reduced, and the hardness of the resulting vegetable milk coagulated food is further increased. In the present invention and this specification, "plant-based milk" refers to a cloudy liquid extracted from plant seeds, etc. (a plant-derived oil-in-water emulsion composition). Specific examples of plant-based milk include, for example, soy milk, almond milk, oat milk, coconut milk, rice milk, chickpea milk, pea milk, etc., and one or more of these can be used. Among these, the plant-based milk preferably contains soy milk, and more preferably soy milk. For example, by adding the hardness enhancer for plant-based milk coagulation foods of the present invention to plant-based milk to pre-emulsify it, and then coagulating it by a conventional method, such as by adding a coagulant, a plant-based milk coagulation food with increased hardness can be obtained. If soy milk is used as the plant-based milk, the resulting plant-based milk coagulation food will be a tofu-like food. In this specification, the tofu-like food product differs from tofu or tofu products, which are simply made by coagulating soy milk, in that it is made by mixing oil and fat containing a certain amount or more of solid fat with soy milk, and then coagulating the pre-emulsified liquid, in which the oil and fat are emulsified and dispersed into fine particles, with the action of a coagulant. Examples of the tofu-like food product include tofu bars, tofu pudding, tofu cream, tofu mousse, and tofu cheese.

[0010] [Hardness improver for plant-based milk coagulation foods] The hardness improver for plant-based milk coagulated foods of the present invention (hereinafter also referred to as "the hardness improver of the present invention") contains oils and fats with a solid fat content of 4% by mass or more at 20°C, and diglycerin fatty acid ester as an emulsifier, wherein the content of the diglycerin fatty acid ester is 0.4 to 3.5% by mass, and the total amount of emulsifiers including diglycerin fatty acid ester is 5.0% by mass or less. When producing plant-based milk coagulated foods, the hardness of the resulting plant-based milk coagulated foods can be improved by mixing the hardness improver of the present invention with plant-based milk beforehand. The hardness enhancer of the present invention can uniformly emulsify plant-based milk as small-particle emulsion particles with a high particle density (a large number of emulsion particles) even when mixed with plant-based milk and stirred under relatively mild conditions. As a result, it is believed that the hardness enhancer of the present invention strengthens the structure by oil crystals and maintains the gel network, making it possible to obtain a plant-based milk coagulated food with high hardness, a uniform and smooth texture, and a less noticeable off-flavor from the emulsifier, as well as superior flavor. Furthermore, by using soy milk as the plant-based milk and incorporating the hardness enhancer of the present invention, it is possible to effectively mask the grassy taste derived from soy milk (soybeans) in the resulting tofu-like food.

[0011] Each component contained in the hardness improver of the present invention is described in detail below.

[0012] The oils and fats used in the hardness improver of the present invention are oils and fats with a solid fat content of 4% by mass or more at 20°C. From the viewpoint of further improving the hardness of the resulting vegetable milk coagulated food, the solid fat content of the oils and fats at 20°C is preferably 6% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, and still more preferably 15% by mass or more. Furthermore, from the viewpoint of making the resulting vegetable milk coagulated food smoother in texture and further improving hardness, the solid fat content of the oils and fats at 20°C is preferably 60% by mass or less, more preferably 55% by mass or less, even more preferably 50% by mass or less, even more preferably 45% by mass or less, and still more preferably 40% by mass or less. The preferred range for the solid fat content of the oils and fats at 20°C is preferably 4 to 60% by mass, more preferably 6 to 60% by mass, even more preferably 8 to 55% by mass, even more preferably 10 to 50% by mass, even more preferably 15 to 45% by mass, and still more preferably 15 to 40% by mass. The solid fat content of oils and fats is measured according to the method described in section 2.2.9 of the Standard Oil and Fat Analysis Test Method established by the Japan Oil Chemists' Association, specifically the NMR method for measuring solid fat content. The oils and fats may be a single type of oil or fat that satisfies the above-mentioned preferred solid fat content, or they may be a mixed oil or fat obtained by mixing two or more types of oils and fats to satisfy the above-mentioned preferred solid fat content.

[0013] As for the oils and fats that can be used in the hardness improver of the present invention, one or more types can be used, selected from animal fats and fats suitable for food, vegetable fats and fats suitable for food, etc., as oily components. Examples of animal fats include lard and beef tallow, and one or more fats selected from these can be used. Examples of vegetable fats include soybean oil, rapeseed oil, corn oil, cottonseed oil, safflower oil, olive oil, palm oil, rice oil, sunflower oil, sesame oil, or hydrogenated oils thereof, transesterified oils thereof, or fractionated oils thereof, and one or more fats selected from these can be used. Furthermore, propylene glycol diester compounds can also be preferably used as oils and fats. The above fats and oils can be used alone or in combination as fats and oils having a solid fat content of 4% by mass or more at 20°C.

[0014] From the viewpoint of reducing the mixing amount with respect to vegetable milk and making a vegetable milk coagulated food with less unpleasant taste of the emulsifier and excellent flavor, the content of the fats and oils in the hardness improver of the present invention is preferably 85% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. Also, the content may be 99% by mass or less, can be 98% by mass or less, and can be 97% by mass or less. When the content is shown in a preferable range, it is preferably 85 to 99% by mass, more preferably 90 to 98% by mass, and further preferably 95 to 97% by mass.

[0015] The hardness improver of the present invention contains diglycerin fatty acid ester as an emulsifier. Diglycerin fatty acid ester has excellent self-emulsifying properties, has fast molecular movement between two phases, and is likely to be oriented at the interface (has a small aggregation energy). Therefore, by blending diglycerin fatty acid ester into the hardness improver of the present invention, the above fats and oils can be emulsified and dispersed uniformly in the form of fine particles in vegetable milk even with a relatively weak shearing force. As a result, the hardness of the obtained vegetable milk coagulated food can be improved.

[0016] ​The content of the diglycerin fatty acid ester in the hardness improver of the present invention is 0.4 to 3.5% by mass. From the viewpoint of making the texture of the obtained plant-based milk coagulated food smoother, the content is preferably 0.6% by mass or more, more preferably 0.8% by mass or more, and even more preferably 1.0% by mass or more. Further, in the obtained plant-based milk coagulated food, from the viewpoint of further suppressing the occurrence of off-flavors derived from the diglycerin fatty acid ester as an emulsifier, the content is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, and even more preferably 2.0% by mass or less. When the content is shown in a preferred range, it is preferably 0.6 to 3.5% by mass, more preferably 0.8 to 2.5% by mass, and even more preferably 1.0 to 2.0% by mass.

[0017] The above diglycerin fatty acid ester preferably has an HLB (Hydrophile-lipophile balance) value of 5 to 10, and more preferably has an HLB value of 4 to 9. The HLB value is a value calculated by the Griffin method (W.C. Griffin, J. Soc. Cosmetic Chemists., 1, 311 (1949)) represented by the following formula. HLB value = 20 × (molecular weight of hydrophilic group part) / (molecular weight of surfactant)

[0018] The above diglycerin fatty acid ester can be synthesized by a usual method and can also be obtained from the market. For example, as commercially available products of diglycerin monooleate, Sansoft No. Q-17D (trade name, manufactured by Taiyo Chemical Co., Ltd.) can be mentioned, and as commercially available products of diglycerin monolaurate, Sansoft No. Q-12D (trade name, manufactured by Taiyo Chemical Co., Ltd.) can be mentioned.

[0019] The hardness improver of the present invention may contain phospholipids as an emulsifier in addition to the above diglycerin fatty acid ester. By the hardness improver of the present invention containing phospholipids, the texture of the obtained plant-based milk coagulated food can be made smoother. As the phospholipids mentioned above, phospholipids derived from natural lecithins such as soy lecithin and egg yolk lecithin, or phospholipids derived from their enzymatic hydrolysates, can be used. Note that commercially available lecithin contains components other than phospholipids (such as oils and fats). However, when using such lecithin, the phospholipids defined in this invention are those contained within the lecithin, and the other components in the lecithin are not included in the phospholipids defined in this invention. For example, if a commercially available lecithin preparation contains oils and fats, these oils and fats are not included in the lecithin defined in this invention, and together with other blended oils and fats (as a mixed oil), they constitute the aforementioned oils and fats (oils and fats with a solid fat content of 4% by mass or more at 20°C). An example of a commercially available lecithin product is Yelkin-TS (trade name, manufactured by Archer Daniels Midland Company).

[0020] When the hardness improver of the present invention contains phospholipids, the phospholipid content in the hardness improver of the present invention is preferably 0.06% by mass or more, more preferably 0.19% by mass or more, and even more preferably 0.32% by mass or more. Furthermore, the content is preferably 2.4% by mass or less, more preferably 1.7% by mass or less, and even more preferably 1.1% by mass or less. Expressed as a preferred range for the content, it is preferably 0.06 to 2.4% by mass, more preferably 0.19 to 1.7% by mass, and even more preferably 0.32 to 1.1% by mass. Furthermore, from the viewpoint of making the texture of the resulting plant-based milk coagulated food smoother, the ratio of the content of diglycerin fatty acid ester to the content of phospholipid (diglycerin fatty acid ester / phospholipid) (mass ratio) is preferably 1 / 2.56 or higher, more preferably 1 / 1.92 or higher, and even more preferably 1 / 1.28 or higher. Furthermore, from the viewpoint of further suppressing the occurrence of off-flavors derived from emulsifiers in the resulting plant-based milk coagulated food, the value of this ratio is preferably 5 / 0.64 or lower, more preferably 4 / 0.64 or lower, and even more preferably 3 / 0.64 or lower. The preferred range for this ratio is preferably 1 / 2.56 to 5 / 0.64, more preferably 1 / 1.92 to 4 / 0.64, and even more preferably 1 / 1.28 to 3 / 0.64.

[0021] The hardness improver of the present invention may contain other emulsifiers in addition to the diglycerin fatty acid ester and phospholipid mentioned above. Examples of such emulsifiers include polyglycerin condensed ricinoleic acid ester, glycerin fatty acid ester, organic acid monoglyceride, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester, and the like, and one or more of these can be used.

[0022] In the hardness improver of the present invention, the total amount of each emulsifier (the sum of the content of diglycerin fatty acid ester, phospholipid, and other emulsifiers) is 5.0% by mass or less. The total amount is preferably 0.4% by mass or more, more preferably 0.6% by mass or more, even more preferably 0.8% by mass or more, and still more preferably 1.0% by mass or more. Furthermore, the total amount of each emulsifier is preferably 4.5% by mass or less, more preferably 4.0% by mass or less, and still more preferably 3.6% by mass or less. The preferred range for the total amount of each emulsifier is preferably 0.4 to 5.0% by mass, more preferably 0.6 to 4.5% by mass, even more preferably 0.8 to 4.0% by mass, and still more preferably 1.0 to 3.6% by mass.

[0023] The hardness improving agent of the present invention is used by being blended into vegetable milk such that its content is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. Alternatively, the hardness improving agent of the present invention is used by being blended into vegetable milk such that its content is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. For example, the hardness improving agent of the present invention is used by being blended into vegetable milk such that its content is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 35% by mass. Furthermore, the hardness improving agent of the present invention can be blended into the vegetable milk such that the oil and fat content in the pre-emulsified liquid is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. Similarly, the hardness improving agent of the present invention can be blended into the vegetable milk such that the oil and fat content in the pre-emulsified liquid is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. The preferred range for the oil and fat content in the pre-emulsified liquid is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 35% by mass. Furthermore, the hardness improving agent of the present invention may be blended into the vegetable milk such that the total amount of emulsifier in the pre-emulsified liquid is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more. Similarly, the hardness improving agent of the present invention may be blended into the vegetable milk such that the total amount of emulsifier in the pre-emulsified liquid is preferably 0.9% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.7% by mass or less. The preferred range for the total amount of emulsifier in the pre-emulsified liquid is preferably 0.1 to 0.9% by mass, more preferably 0.2 to 0.8% by mass, and even more preferably 0.3 to 0.7% by mass.

[0024] The hardness improver of the present invention is mixed with vegetable milk and pre-emulsified. As described above, the hardness improver of the present invention contains diglycerin fatty acid ester, so even when stirred under relatively mild conditions, an emulsified liquid (pre-emulsified liquid) can be obtained in which small-particle-sized emulsion particles are uniformly emulsified in the vegetable milk at a high particle density (a large number of emulsion particles are present). In this pre-emulsified liquid, the median diameter (also called the median diameter of the emulsion particles) of the oil droplets containing the hardness improver of the present invention (meaning oil droplets containing oils and fats derived from the hardness improver of the present invention and oils and fats derived from vegetable milk, etc.) is preferably 60 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. In addition, the particle diameter is usually 1 μm or more, and preferably 5 μm or more. The median diameter can be determined by the method described in the examples below. Furthermore, the stirring conditions described above are not particularly limited, and conditions can be applied that allow the oils and fats contained in the hardness improver of the present invention to be emulsified and dispersed in the vegetable milk in the form of fine particles. For example, by preheating the hardness improver of the present invention to 70-90°C, mixing it with vegetable milk (70-90°C), and stirring it at 500-6000 rpm for 0.5-5 minutes using a known emulsifying and dispersing machine, a preliminary emulsified liquid in which oil droplets are emulsified and dispersed in the form of fine particles can be obtained.

[0025] As described above, the pre-emulsified liquid obtained by stirring can then be coagulated by a conventional method and further aged to obtain a plant-based milk coagulated food. For example, if the plant-based milk is soy milk, a coagulant (nigari) containing magnesium chloride or the like can be added to the obtained pre-emulsified liquid to emulsify and disperse it, and then coagulate and age it to obtain a tofu-like food with increased hardness. In the production of tofu-like foods, in the coagulation step, it is preferable to mix the pre-emulsion and the coagulant so that the magnesium chloride content in the pre-emulsion is about 0.1 to 0.3% by mass. The dispersion of the coagulant in the pre-emulsion can be carried out, for example, by stirring at a desired stirring speed using a stirring device such as a milder (MDN303V, rotor-stator G / M / F, manufactured by Pacific Machine Works Co., Ltd.) or a homomixer (TK homomixer MARKII, manufactured by Primix Corporation). The temperature of this dispersion treatment can be appropriately adjusted within the range of 20 to 90 °C (preferably 90 °C or lower, more preferably 85 °C or lower). Thereafter, the tofu-like food can be obtained by subjecting it to an aging step. For example, after mixing the pre-emulsion and the coagulant within the above temperature range and stirring for several seconds to several tens of seconds, it is filled into a filling container and a continuous molding machine of a desired shape, and heated and aged, for example, at a temperature of about 80 to 90 °C for about 40 to 50 minutes, whereby a tofu-like food can be obtained.

[0026] The hardness improver of the present invention is mixed with vegetable milk to form a pre-emulsion, and the vegetable milk coagulated food obtained using the pre-emulsion has improved hardness, a smooth texture, and excellent flavor. The hardness (breaking stress) of such a vegetable milk coagulated food is preferably 99 gf / cm 2 or more, more preferably 110 gf / cm 2 or more, and even more preferably 118 gf / cm 2 or more. Also, the hardness can be 250 gf / cm 2 or less, may be 230 gf / cm 2 or less, or may be 200 gf / cm 2 or less. The breaking stress can be measured, for example, by the method described in the examples. For example, the hardness of the obtained tofu-like food is preferably 99 to 250 gf / cm 2 and more preferably 110 to 230 gf / cm 2 and even more preferably 118 to 200 gf / cm 2

[0027] ​In addition to the method described above for obtaining a plant-based milk coagulated food using the hardness-improving agent of the present invention, the present invention also provides a method for producing a plant-based milk coagulated food that does not require the use of the diglycerin fatty acid ester described above (a method according to the second embodiment, a second method). Specifically, an oil having a solid fat content of 4% by mass or more at 20°C is heated to 70-90°C and added to plant-based milk. A preliminary emulsified solution is prepared by stirring with a stronger shear force so that the median diameter of the emulsion particles (oil droplets) in the plant-based milk becomes 60 μm or less. This is then usually coagulated by a conventional method, and if necessary, aged by a conventional method to obtain a plant-based milk coagulated food with improved hardness. Even without using an emulsifier, a plant-based milk coagulated food with the desired hardness can be obtained by preparing a preliminary emulsified solution by emulsifying and dispersing with a high shear force. In the second manufacturing method, the type of vegetable milk used, the type of oils and fats added thereto, the content of oils and fats in the mixed solution (pre-emulsified solution) of vegetable milk, and the median diameter of the emulsion particles in the pre-emulsified solution can be referenced from the above-mentioned description in the method for producing vegetable milk coagulated food using the hardness improver of the present invention. Furthermore, the type of emulsifier that can be used as necessary in the preparation of the pre-emulsified solution and the total amount of emulsifier in the pre-emulsified solution can be referenced from the above-mentioned description regarding emulsifiers that can be used with the hardness improver of the present invention and their total amount. Examples of agitators that generate the high shear force mentioned above include Milder (MDN303V, rotor / stator G / M / F, manufactured by Taiheiyo Kiko) and Homomixer (TK Homomixer MARKII, manufactured by Primix). In the process of preparing this pre-emulsified liquid, the plant-based milk is preferably heated to 70-90°C and stirred at 70-90°C for 1-3 minutes at, for example, 5000-14000 rpm. The median diameter of the emulsion particles can be determined by the method described in the examples below.

[0028] For example, if the plant-based milk is soy milk, an oil having a solid fat content of 4% by mass or more at 20°C is heated to 70-90°C and added to the soy milk. The mixture is then stirred to prepare a preliminary emulsified solution, and typically, a coagulation step is performed by dispersing a coagulant (such as nigari) containing magnesium chloride or the like in the preliminary emulsified solution to solidify it. This is followed by a maturation step involving heat treatment, which increases the hardness and provides a good flavor, thereby obtaining a tofu-like food product. The coagulation and maturation steps in the production of the tofu-like food product by the second method can be appropriately adapted from the description of the method for producing a tofu-like food product using the hardness-improving agent of the present invention described above.

[0029] The present invention will be described in more detail below based on examples, but the present invention is not limited thereto. [Examples]

[0030] <Method for measuring solid fat content> The solid fat content (SFC) (20°C) of the oils and fats used in this example was measured in accordance with the method described in section 2.2.9 Solid Fat Content (NMR Method) of the Standard Oil and Fats Analysis Test Method established by the Japan Oil Chemists' Society, as follows. NMR measuring device for solid fat content measurement (MQC + SFC was measured using a benchtop TD-NMR spectrometer (OXFORD INSTRUMENTS). The sample and control sample (pharmacopoeial olive oil), packed in test tubes, were heated in an 80°C constant temperature bath to homogenize them, then placed back into separate test tubes and sealed with rubber stoppers. The sample and control samples packed in test tubes were held at 60°C for 30 minutes, then at 0°C for 30 minutes, then at 25°C for 30 minutes, then at 0°C for 30 minutes, and finally at 20°C for 30 minutes. From the NMR signals of each sample, SFC(20°C) was calculated using the following formula. SFC(20℃)(%)=[1-{(A / B)×(D / C)}]×100 A: Reading of the NMR signal of the control sample at 60°C. B: Reading of the NMR signal of the sample at 60°C C: Reading of the NMR signal of the control sample at 20°C D: Reading of the NMR signal of the sample at 20°C.

[0031] (Examples 1-14, Comparative Examples 1-4) The hardness improvers for Examples 1-14 and Comparative Examples 1-4 were obtained by mixing the raw materials according to the formulations (unit: parts by mass) shown in Tables 1 and 2 below. The raw materials used for each hardness improver were as follows. -Oils- • Oil A: A mixture of transesterified oils of palm oil, coconut oil, and super olein, super olein, and refined rapeseed oil, SFC (20℃) 11% • Oil B: A blend of palm oil and superolein, SFC (20℃) 19% • Fats and Oils C: A mixture of hydrogenated coconut oil, palm oil, transesterified palm oil, rapeseed oil, and high-erucine rapeseed oil, SFC (20℃) 49% • Corn oil: Nissin Corn Oil (S) (product name), manufactured by Nissin Oillio Group Ltd., SFC (20℃) 0% -emulsifier- • Diglycerin fatty acid ester A: Diglycerin monooleate, Sunsoft No. Q-17D (product name), HLB 6.5, manufactured by Taiyo Kagaku Co., Ltd. • Diglycerin fatty acid ester B: Diglycerin monolaurate ester, Sunsoft No. Q-12D (product name), HLB 8.5, manufactured by Taiyo Kagaku Co., Ltd. • Lecithin: Yelkin-TS (brand name), phospholipid content 64% by mass, manufactured by Archer Daniels Midland Company.

[0032] [Preparation Example 1] Production of tofu-like food using a hardness improver (1) Soy milk (soybean variety 2021 Ginga, Brix 11.9) and each hardness improver from Examples 1-14 and Comparative Examples 1-4 were heated to 80°C. 100g of each hardness improver was added to 400g of the soy milk and stirred at 3000rpm for 1 minute using a homomixer (product name: TK Homomixer MARK II, manufactured by Primix Corporation) to obtain a preliminary emulsified solution. The obtained pre-emulsified solution (temperature adjusted to 60°C) and a coagulant (Magnesfine TG, manufactured by Kao Corporation) were mixed using a homomixer (product name: TK Homomixer MARK II, manufactured by Primix Corporation) at 5000 rpm for 20 seconds to disperse the coagulant in the pre-emulsified solution (magnesium chloride concentration in the emulsified solution: 0.3%), and then coagulated. After that, the mixture was aged at 80°C for 40 minutes and cooled at 5°C for 24 hours to obtain each of the tofu-like food products in Preparation Examples 1 to 18. The following tests were performed on each of the obtained tofu-like food products. For reference, the same tests were also conducted on tofu produced without the use of a hardness improver.

[0033] [Test Example 1] Compression fracture test of tofu-like food product Each tofu-like food product from Preparation Examples 1-18 was placed in a cylinder with a diameter of 28 mm and a height of 15 mm (top surface area of ​​the sample: 6.15 cm²). 2 Four pieces were cut from the sample, and a compression fracture test was performed using a small benchtop testing machine (Ez-TEST, manufactured by Shimadzu Corporation). The test was conducted using a 50 mm diameter plastic plunger. The maximum strength (test force, gf) was measured when the plunger was lowered to the 60% strain point at a speed of 30 mm / min during the compression fracture test, and the fracture stress was calculated using the following formula (Equation 1). The average of the four calculated values ​​obtained was used to determine the hardness (gf / cm²) of the tofu-like food product. 2 The results are shown in Tables 1 and 2. Breaking stress [gf / cm] 2 ] = Test force [gf] / Sample area [cm²] 2 ]...(Formula 1)

[0034] [Test Example 2] Sensory evaluation of tofu-like food products The flavor of each tofu-like food product (Preparation Examples 1-18) was scored according to the evaluation criteria below, and the average scores of three expert panel members were compared. The evaluation results of all three panel members were identical. The results are shown in Tables 1 and 2. -Flavor Evaluation Criteria- 4. No off-flavors from emulsifiers are detected. 3: There is almost no off-flavor from the emulsifier. 2: I can detect an off-flavor from the emulsifier, but it's not too bothersome. 1: The off-flavor derived from the emulsifier is more strongly noticeable.

[0035] Furthermore, if succinic acid monostearate, monooleic acid ester, pentaglycerin trioleate, pentaglycerin trimyristate, decaglycerin monooleate, polyglycerin condensed ricinoleate, sorbitan monostearate, or polyoxyethylene sorbitan monostearate is used instead of diglycerin fatty acid ester as the emulsifier in the hardness improver of Example 2, the breaking stress of the resulting tofu-like food product will be 99 gf / cm². 2 The result was less than the desired hardness improvement effect.

[0036] [Table 1]

[0037] [Table 2]

[0038] Table 1 shows that the reference example tofu, produced without a hardness improver, did not exhibit any off-flavors derived from the emulsifier, but its fracture stress was low. Furthermore, the tofu-like foods produced using the hardness improvers in Comparative Example 1 (which did not contain diglycerin fatty acid ester) and Comparative Example 3 (which did not contain solid fat) (Preparation Examples 1 and 6) did not achieve a sufficient level of fracture stress. Moreover, the tofu-like food produced using the hardness improver in Comparative Example 2 (Preparation Example 5), which contained more diglycerin fatty acid ester than the specified amount, exhibited a stronger off-flavor derived from the emulsifier. In contrast, the tofu-like foods (Preparation Examples 2-4, 7-10) obtained using the hardness improvers of Examples 1-7 that satisfy the provisions of the present invention all exhibited sufficiently increased hardness, and off-flavors derived from emulsifiers were hardly noticeable. Furthermore, compared to the hardness improvers of Comparative Examples 1, 3, and 4, the tofu-like foods obtained using the hardness improvers of Examples 1-7 had a smoother texture, and there was almost no grassy odor derived from soybeans.

[0039] Furthermore, as shown in Table 2, in Comparative Example 4, which used the hardness improver from Example 2 but with the same amount of lecithin instead of diglycerin fatty acid ester, the tofu-like food product (Preparation Example 11) produced using this product did not show a sufficient improvement in fracture stress, nor did it have a smooth texture. In contrast, the tofu-like foods (Preparation Examples 12-18) produced using the hardness improvers from Examples 8-14, which contained lecithin in addition to diglycerin fatty acid ester, all tended to exhibit higher hardness. The tofu-like foods produced using the hardness improvers from Examples 8-14 all showed a smoother texture and had almost no grassy odor derived from soybeans.

[0040] [Preparation Example 2] Production of tofu-like food using a hardness improver (2) Tofu-like food products were prepared in the same manner as in Preparation Example 1 (Preparation Examples 19-22), except that the amount of hardness improver added to soy milk was as shown in Table 3 below. Fracture stress measurements and sensory evaluation tests were performed on the obtained tofu-like food products in the same manner as above. The results are also shown in Table 3 below.

[0041] [Table 3]

[0042] As is clear from Table 3, the tofu-like foods prepared in Examples 19-22, obtained by adding the hardness improver of Example 1 to the soy milk in an amount of 10-40% by mass to obtain a preliminary emulsified solution, all showed increased fracture stress in a dosage-dependent manner and had good flavor.

[0043] [Preparation Example 3] Production of tofu-like food by the method according to the second embodiment The soy milk and oil A were mixed so that the oil A content in the soy milk was 20% by mass. The mixture was then emulsified using a homomixer (Primex TK Homomixer MARK II) under the stirring conditions (3000-8000 rpm, 1-2 minutes) described in Table 4 below to obtain a preliminary emulsified solution. Using the obtained preliminary emulsified solution, each tofu-like food product (Preparation Examples 23-25) was obtained in the same manner as in Preparation Example 1. A fracture stress test was performed on each of the obtained tofu-like food products in the same manner as described above. The results are also shown in Table 4 below.

[0044] [Test Example 3] Median diameter of oils and fats in pre-emulsified solution For the above-mentioned preliminary emulsified solution, the median diameter (volume-based, refractive index 1.70-0.20i) of the emulsion particles was measured using a laser diffraction particle size distribution analyzer (SALD-2100, Shimadzu Corporation). Ion-exchanged water was used as the dispersion medium, and measurements were performed using the flow cell method in the range of 20°C to 25°C. The results are shown in Table 4 below.

[0045] [Table 4]

[0046] Table 4 shows that in the pre-emulsified liquid prepared by stirring with a TK mixer at 3000 rpm for 1 minute, the particle size of the emulsion particles was large, and the tofu-like food obtained using this pre-emulsified liquid did not show sufficient improvement in fracture stress (Preparation Example 23). In contrast, in the pre-emulsified liquid prepared under stronger stirring conditions, the particle size of the emulsion particles was smaller, and the tofu-like food obtained using this pre-emulsified liquid showed good flavor while exhibiting sufficiently high fracture stress (Preparation Examples 24, 25). Furthermore, the tofu-like food products of Preparation Examples 24 and 25 also had a smooth texture.

[0047] In summary, it has been shown that by preparing a pre-emulsified solution by emulsifying and dispersing an oil or fat having a certain amount of solid fat content in plant-based milk, and by controlling the particle size of the emulsion particles in the pre-emulsified solution to be smaller, the hardness of the plant-based milk coagulated food obtained using the pre-emulsified solution can be increased, and the flavor can also be improved.

Claims

1. A hardness enhancer for vegetable milk coagulation foods, comprising oils and fats with a solid fat content of 4% by mass or more at 20°C, and a diglycerin fatty acid ester, wherein the content of the diglycerin fatty acid ester is 0.4 to 3.5% by mass, and the total amount of emulsifier is 5.0% by mass or less.

2. It contains phospholipids, The hardness enhancer for plant-based milk coagulation foods according to claim 1, wherein the ratio of the content of the diglycerin fatty acid ester to the content of the phospholipid is 1 / 2.56 or more by mass.

3. The hardness improver for plant-based milk coagulation foods according to claim 2, wherein the content of the hardness improver for plant-based milk coagulation foods in the plant-based milk is 10 to 40% by mass.

4. The hardness enhancer for plant-based milk coagulated foods according to claim 3, wherein the plant-based milk is soy milk.

5. A method for producing a plant-based milk coagulated food, comprising the step of mixing a hardness improver for plant-based milk coagulated foods according to claims 1 to 4 with plant-based milk to prepare a pre-emulsified solution.

6. The process includes adding an oil having a solid fat content of 4% by mass or more at 20°C to vegetable milk after adjusting the temperature to 70-90°C, and stirring the mixture so that the median diameter of the emulsion particles in the vegetable milk is 60 μm or less to prepare a preliminary emulsified solution. A method for producing plant-based milk coagulated food products.

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