Coagulant for soybean curd and production method of soybean curd using the same

Abstract

To provide a technique which suppresses generation of white oil droplets (floating matters) which occur when soybean curd is produced in coagulant for soybean curd in which water-in-oil type emulsion containing polyglycerol condensed ricinoleic acid ester in an oil phase is set to be active ingredients.SOLUTION: Provided are: coagulant for soybean curd sets water-in-oil type emulsion having vegetable oil and polyglycerol condensed ricinoleic acid ester as an oil phase and magnesium chloride aqueous solution as a water phase as active ingredients, the coagulant for soybean curd containing rice bran wax and / or carnauba wax in a mass ratio of 0.01 to 0.12 relative to polyglycerol condensed ricinoleic acid ester in the oil phase; and a producing method of bean curd using the same.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a tofu coagulant in the form of a water-in-oil emulsion and a method for producing tofu using the same. [Background technology]

[0002] Tofu is produced by adding a coagulant such as bittern to soy milk to cross-link the soy protein and create a gel. Magnesium chloride is often used as this coagulant, as it imparts a mild sweetness and enhances the soy flavor of the tofu. However, the coagulation action of magnesium chloride (cross-linking and gelling of soy protein) is very rapid, and the coagulation reaction proceeds quickly before the soy protein can be uniformly dispersed throughout the soy milk. Therefore, to obtain high-quality tofu with a highly uniform gelatinized structure, it is necessary to operate on a small scale and to employ skilled techniques.

[0003] To produce tofu with a uniform cross-linked soy protein gel structure using magnesium chloride as a coagulant, tofu coagulants have been developed that control the immediate effect and the delayed effect by incorporating fats and oils and emulsifiers to form a water-in-oil emulsion with magnesium chloride as the internal phase. Patent Document 1 proposes a water-in-oil emulsion coagulant in which vegetable oils and polyglycerol condensed ricinoleic acid ester are homogeneously emulsified as the oil phase with an aqueous magnesium chloride solution as the water phase. Patent Document 2 also proposes a microparticulated coagulant in which magnesium chloride containing a polyhydric alcohol and dextrin is mixed and dispersed in an oil phase consisting of a propylene glycol fatty acid ester containing polyglycerol condensed ricinoleic acid ester.

[0004] The magnesium chloride coagulant in the form of a dispersion and emulsion in oil described in the above patent documents significantly controls the immediate effect of magnesium chloride in the tofu coagulation process, i.e., it can impart a delayed effect, and coupled with the spread of continuous automatic tofu coagulation and manufacturing systems, mass production of tofu has become established, leading to industrial development of the tofu manufacturing industry over the past 25 years. Furthermore, patent documents 3 and 4 describe efforts to increase the concentration of magnesium chloride in tofu coagulants, which are water-in-oil emulsions.

[0005] In both cases, polyglycerol condensed ricinoleate, a powerful water-in-oil emulsifier with excellent salt tolerance, is essential for emulsion-type coagulant formulations that mainly contain magnesium chloride, and as the magnesium chloride concentration in the coagulant increases, the concentration of polyglycerol condensed ricinoleate in the oil phase must also increase. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-32942 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-101848 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-100280 [Patent Document 4] International Publication No. WO2019 / 224892 Brochure Summary of the Invention [Problem to be solved by the invention]

[0007] Tofu coagulant preparations using polyglycerol condensed ricinoleate can impair the flavor of the tofu due to the off-flavor characteristic of polyglycerol condensed ricinoleate if added in excessive amounts. Furthermore, preparations using polyglycerol condensed ricinoleate are characterized by their strong emulsifying power, making them difficult to disperse in soy milk. Therefore, unless they are stirred with strong shearing force, uneven coagulation occurs, and white oil droplets remain in the tofu (Figure 1), which can adhere in granular form to the film or packaging. Furthermore, when cooked, these particles appear as floating particles in dishes such as boiled tofu, leading to complaints.

[0008] In mass production using a continuous molding line, the slow-acting effect of polyglycerol condensed ricinoleate dramatically increases production efficiency, but in the production of cut silk products and cotton tofu, which undergoes a breaking process, these white oil droplets adhere to the belt line and cause wastewater contamination in the water-washing process, and in large-scale factories today, in particular, huge costs are spent on wastewater treatment.The present applicant was the first to discover that the presence of these white oil droplets causes various problems in tofu production.

[0009] An object of the present invention is to provide a technology for suppressing the generation of white oil droplets (floating matter) that occur during tofu production in a tofu coagulant that contains, as an active ingredient, a water-in-oil emulsion containing a polyglycerol condensed ricinoleate ester as described above in the oil phase. [Means for solving the problem]

[0010] As a result of intensive research to solve the above problems, the present inventors discovered that the generation of white oil droplets during tofu production can be suppressed by adding a specific type of wax in a specific amount to the oil phase, and thus completed the present invention.

[0011] That is, the present invention provides a tofu coagulant containing, as an active ingredient, a water-in-oil emulsion having an oil phase comprising a vegetable oil and a polyglycerol condensed ricinoleate, and an aqueous magnesium chloride solution as an aqueous phase, The tofu coagulant is characterized in that it contains rice bran wax and / or carnauba wax in a mass ratio of 0.01 to 0.12 relative to the polyglycerin condensed ricinoleate in the oil phase.

[0012] The present invention also provides a method for producing tofu, which comprises using the above-mentioned tofu coagulant in the production of tofu. [Effects of the Invention]

[0013] The tofu coagulant of the present invention can suppress the generation of white oil droplets during tofu production, which is useful for improving the quality of tofu products and preventing problems on production lines. Furthermore, the use of the tofu coagulant of the present invention also improves the taste of the tofu produced. [Brief explanation of the drawings]

[0014] [Figure 1] This is a photograph showing white oil droplets (floating matter) rising to the surface of water after silken tofu (400 g) coagulated with a conventional tofu coagulant containing 6% by mass of polyglycerol condensed ricinoleate was crumbled in a 2 L beaker with three turns of a whisk. [Figure 2] FIG. 1 is a diagram showing the state of silken tofu in a mold box after it has been uniformly crumbled with a whisk in Test Example 1. [Figure 3] 1 is a diagram showing white oil droplets (floating matter) collected by separating the supernatant into a mold box in Test Example 1. FIG. [Figure 4] FIG. 1 is a diagram showing white oil droplets (floating matter) recovered and filtered in Test Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0015] The tofu coagulant of the present invention contains, as an active ingredient, a water-in-oil emulsion having an oil phase consisting of vegetable oil and polyglycerol condensed ricinoleate and an aqueous magnesium chloride solution as the water phase, and contains rice bran wax and / or carnauba wax in a mass ratio of 0.01 to 0.12 relative to the polyglycerol condensed ricinoleate in the oil phase.

[0016] The vegetable oil used above is not particularly limited as long as it is edible, and examples thereof include soybean oil, rapeseed oil, cottonseed oil, safflower oil, sunflower oil, rice bran oil, corn oil, coconut oil, palm oil, olive oil, etc. These vegetable oils can be used alone or in combination of two or more. These vegetable oils are limited to those that are liquid at room temperature.

[0017] The polyglycerol condensed ricinoleate used above is called PGPR. There are no particular restrictions on the number of glycerol units in the glycerol polymer constituting the polyglycerol condensed ricinoleate, but from the viewpoint of emulsion stability, it is preferable that the degree of glycerol polymerization (average degree of polymerization) is 4 to 6. From the same viewpoint, it is also preferable that the condensed ricinoleic acid in the polyglycerol condensed ricinoleate has a structure in which 2 to 5 molecules of ricinoleic acid are condensed. These polyglycerol condensed ricinoleic esters can be used alone or in combination of two or more.

[0018] The physical properties of the polyglycerol condensed ricinoleate are not particularly limited, and the acid value, hydroxyl value, iodine value, etc. may be within the general ranges that can be used as a tofu coagulant.

[0019] The polyglycerol condensed ricinoleate ester used above can be synthesized by a conventional method. Alternatively, commercially available polyglycerol condensed ricinoleate esters may be used, such as those available under the trade names MASEMULL PGPR9090 (manufactured by PT. MUSIM MAS), SUNSOLFT No. 818SK (manufactured by Taiyo Kagaku Co., Ltd.), SUNSOLFT No. 818R (manufactured by Taiyo Kagaku Co., Ltd.), SY Glystar CR-500 (manufactured by Sakamoto Pharmaceutical Co., Ltd.), and Poem PR-300 (manufactured by Riken Vitamin Co., Ltd.).

[0020] The rice bran wax and / or carnauba wax used above is not particularly limited, but examples include those having a melting point of 70 to 90° C., preferably 73 to 87° C. Among these, rice bran wax with a melting point of 80° C. and / or carnauba wax with a melting point of 83° C. are preferred. These are commercially available under the trade names Refined Rice Wax S-100 (manufactured by Yokoseki Yushi Kogyo Co., Ltd.) and Refined Carnauba Wax R-100 (manufactured by Yokoseki Yushi Kogyo Co., Ltd.), respectively, and these can be used.

[0021] In the tofu coagulant of the present invention, the content of the polyglycerol condensed ricinoleate in the oil phase is not particularly limited, but is, for example, 6.0 to 20.0 mass% (hereinafter simply referred to as "%"), preferably 8.0 to 16.0%. The content of the polyglycerol condensed ricinoleate in the tofu coagulant is also not particularly limited, but is, for example, 1.8 to 8.0%, preferably 2.4 to 5.0%.

[0022] The oil phase contains rice bran wax and / or carnauba wax in a mass ratio of 0.01 to 0.12, preferably 0.02 to 0.10, relative to the polyglycerol condensed ricinoleate. The oil phase may contain either rice bran wax or carnauba wax, but it is preferable to contain both, and it is particularly preferable to contain rice bran wax and carnauba wax in a mass ratio of 70:30 to 30:70, preferably 70:30 to 50:50.

[0023] The method for incorporating rice bran wax and / or carnauba wax into the oil phase is not particularly limited, but examples include heating a portion of the vegetable oil used to form the oil phase to a temperature above the melting point of the rice bran wax and / or carnauba wax, for example, to 90 to 100°C, dissolving the rice bran wax and / or carnauba wax in the oil, and then rapidly cooling the mixture to 50°C or below. After rapid cooling, microcrystals of the rice bran wax and / or carnauba wax precipitate in the vegetable oil. Here, the term "microcrystals" refers to particles with a median diameter of 100 μm or less, preferably 30 μm or less, as measured using a laser diffraction particle size distribution analyzer SALD-2300 (Shimadzu Corporation).

[0024] The oil phase is prepared by mixing the vegetable oil containing rice bran wax and / or carnauba wax as described above with the remaining vegetable oil mixed separately with polyglycerol condensed ricinoleate in a stirrer or the like.

[0025] The oil phase may contain, if necessary, for example, monoacylglycerol, polyol fatty acid esters such as sorbitan fatty acid esters, etc., but it is preferable that the oil phase consists of the above components.

[0026] The magnesium chloride aqueous solution used above is not particularly limited as long as it is an aqueous solution containing magnesium chloride, but for example, the concentration of magnesium chloride hexahydrate is 50 to 70%, preferably 60 to 70%. Such an aqueous magnesium chloride solution can be prepared by dissolving magnesium chloride hexahydrate in water to the above concentration, and using this as the aqueous phase.

[0027] The aqueous phase may contain inorganic salts such as calcium chloride, if necessary, but it is preferable that the aqueous phase consists of the above components.

[0028] The method for obtaining a water-in-oil emulsion from the oil phase and the aqueous phase is not particularly limited, but a conventional emulsification / dispersion method can be used. For example, a method in which the aqueous phase is added dropwise to a heated oil phase while stirring with a stirrer such as a homomixer can be used. The heating temperature is not particularly limited, but is 40°C or higher, preferably 50 to 70°C. The stirring may be performed in two stages: preliminary emulsification and main emulsification.

[0029] The mass ratio of the aqueous phase to the oil phase in the water-in-oil emulsion is not particularly limited, but for example, the aqueous phase / oil phase ratio is 60 / 40 to 75 / 25, preferably 60 / 40 to 70 / 30.

[0030] Preferred embodiments of the water-in-oil emulsions described above include the following. Oil phase: Consists of vegetable oil, polyglycerol condensed ricinoleate, rice bran wax, and carnauba wax, and contains rice bran wax and carnauba wax in a mass ratio of 0.01 to 0.12 relative to the polyglycerol condensed ricinoleate, with the mass ratio of rice bran wax and carnauba wax being 70:30 to 50:50. Aqueous phase: Consists of an aqueous magnesium chloride solution. The concentration of magnesium chloride hexahydrate in the aqueous phase is 60 to 70 mass %, the concentration of polyglycerol condensed ricinoleate in the oil phase is 6 to 20 mass %, and the aqueous phase / oil phase ratio is 60 / 40 to 70 / 30.

[0031] The tofu coagulant of the present invention may contain the water-in-oil emulsion obtained as described above as an active ingredient, and may be diluted as appropriate.

[0032] The tofu coagulant of the present invention can coagulate proteins by adding it to heated soy milk, and can therefore be used in the production of tofu simply by replacing conventional tofu coagulants. The tofu for which the tofu coagulant of the present invention can be used is not particularly limited, and examples include firm tofu, silken tofu, and packed tofu. When using the tofu coagulant of the present invention in the production of tofu, the amount added can be appropriately determined depending on the type of tofu to be produced, and the tofu coagulant of the present invention can be added in the same amount as conventional soy milk coagulants, for example, based on the amount of magnesium chloride.

[0033] The tofu coagulant of the present invention can suppress the generation of white oil droplets (floating matter) that occur during tofu production, thereby improving the quality of tofu products and suppressing problems on production lines. Whether the generation of white oil droplets (floating matter) has been suppressed can be confirmed, for example, by repeatedly breaking down the tofu after production, adding water, leaving it to stand, and separating the supernatant, recovering the white oil droplets (floating matter), and measuring the amount of the recovered white oil droplets (floating matter).

[0034] Furthermore, the tofu produced using the tofu coagulant of the present invention has an improved flavor as compared to tofu produced using only polyglycerol condensed ricinoleate.

[0035] Furthermore, this tofu may be processed into, for example, grilled tofu, fried tofu, fried tofu, ganmodoki, thick fried tofu, etc. [Example]

[0036] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0037] Manufacturing Example 1 Oil phase sample preparation: An oil phase sample was prepared by blending 30% PGPR oil, 5% WAX oil, and rapeseed oil as shown in Table 1. Nissin Rapeseed Salad Oil S (manufactured by Nissin Oillio) was used as the rapeseed oil. MASEMUUL PGPR9090 (manufactured by PT. MUSIM MAS) (acid value 0.70, hydroxyl value 86, iodine value 85) was used as the polyglycerol condensed ricinoleate (abbreviated as PGPR). First, 30% PGPR was dissolved in rapeseed oil to prepare 30% PGPR oil.

[0038] The 5% wax oil used above was prepared as follows: 30 g of rice wax and 20 g of carnauba wax were blended with 450 g of rapeseed oil and heated to 90°C until completely dissolved. The rapeseed oil in which the waxes had been completely dissolved was mixed with 500 g of rapeseed oil cooled to below 5°C under stirring, and the mixture was rapidly cooled to below 50°C to prepare a 5% wax oil containing 5% wax microcrystals (median diameter: 10-15 μm). Refined rice wax S-100 (manufactured by Yokoseki Yushi Kogyo Co., Ltd.; melting point 80°C) was used as the rice bran wax, and refined carnauba wax R-100 (manufactured by Yokoseki Yushi Kogyo Co., Ltd.; melting point 83°C) was used as the carnauba wax.

[0039] [Table 1]

[0040] Examples 1 to 8, Comparative Examples 1 to 7 Tofu coagulant preparation: Tofu coagulants (Inventions 1-8, Comparative Examples 1-7) consisting of water-in-oil emulsions were prepared with the blending compositions (mass %) shown in Table 2. For the 70% magnesium chloride aqueous solution shown in Table 2, Soft Wafer (trade name: manufactured by Ako Kasei) was used as magnesium chloride hexahydrate (MgCl2·6H2O).

[0041] The aqueous phase (70% magnesium chloride solution) and the oil phase sample (oil phase sample) were heated to 60°C. The 70% magnesium chloride solution was added dropwise to the oil phase sample while stirring at 5500 rpm for 5 minutes using a homomixer (TK homomixer MARK II, manufactured by Primix) to obtain a water-in-oil pre-emulsion. This pre-emulsion was passed through a Milder (MDN303, manufactured by Pacific Machinery Works) once at a generator (Δ / G / M) of 9000 rpm and a flow rate of 600 ml / min to obtain a water-in-oil emulsion for tofu coagulation.

[0042] [Table 2]

[0043] Test Example 1 Evaluation of coagulation of soy milk using tofu coagulant and recovery of white oil droplets (floating matter): Tofu was produced using the Brix 12 soy milk obtained from soybeans (2022 Canadian W4 white) and the tofu coagulant prepared above. Specifically, using a coagulant dispersion system mag (model: TK-42, manufactured by Earth System 21), 36 g of tofu coagulant equivalent to magnesium chloride hexahydrate was continuously added to 10 kg of soy milk maintained at 82°C through a flow pipe. Immediately after addition, the soy milk / tofu coagulant dispersion was dispersed at high speed using a TK homomixer. The resulting mixture was poured into a mold box (430 x 300 x 120 mm, made of stainless steel). After the entire amount was poured, it was aged for 20 minutes to produce silken tofu.

[0044] At this time, the time (delayed action: in seconds) until the fluidity of the dispersion in the mold box after the entire amount was poured (the soy milk began to coagulate) was set to 25 seconds, and silken tofu was produced at a level equivalent to that of delayed action. The state of coagulation of the silken tofu in the mold box was evaluated for hardness using a round (stick) Marucho type simple hardness tester. The results are shown in Table 3.

[0045] Next, the silken tofu in the mold box was uniformly broken down using a whipper 10 times, pressed under pressure, reshaped, soaked in water, cut, and packed to obtain firm tofu. During this process, the silken tofu in the mold box was uniformly broken down using a whipper (Figure 2: the white part is tofu). Water was added, the mixture was allowed to stand, and the supernatant was separated. All of the white oil droplets (floating matter) that rose to the surface were collected. Figure 3 shows the white oil droplets (floating matter) collected by separating the supernatant in the mold box. The supernatant containing the white oil droplets (floating matter) was filtered out using a glass filter. The filtered white oil droplets (floating matter) were transferred to a petri dish (Figure 4) and air-dried overnight. The mass of the white oil droplets (floating matter) in the contents was measured. The results are also shown in Table 3.

[0046] [Table 3]

[0047] The amount of white oil droplets generated increased with the PGPR content in the tofu coagulant. Comparisons between Examples 2 and 4 and Comparative Examples 2 and 3 revealed that a lower PGPR concentration in the oil phase reduced the amount of white oil droplets generated. Furthermore, the presence of rice bran wax and / or carnauba wax in a mass ratio of 0.12 to 0.01 relative to PGPR maintained the firmness of silken tofu while reducing the generation of white oil droplets to 1 / 3 to 1 / 5. Tofu coagulants containing 4.8% or less PGPR in the coagulant were particularly effective in suppressing the generation of white oil droplets, and are useful for improving the quality of tofu products and preventing problems on production lines. Furthermore, the flavor of the tofu produced using the tofu coagulants of Examples 1 to 8 was improved compared to that of Comparative Examples 1 to 8.

[0048] When the white oil droplets (floating matter) from the above examples and comparative examples were freeze-dried and their moisture content was measured, they were found to contain 86 to 96% moisture, and it is estimated that the white oil droplets (floating matter) are aggregates of a highly water-in-oil emulsion. [Industrial Applicability]

[0049] The tofu coagulant of the present invention can be used in the production of tofu.

Claims

1. A tofu coagulant containing, as an active ingredient, a water-in-oil emulsion having an oil phase composed of vegetable oil and polyglycerol condensed ricinoleate and an aqueous magnesium chloride solution as an aqueous phase, A tofu coagulant comprising rice bran wax and / or carnauba wax in a mass ratio of 0.01 to 0.12 relative to the polyglycerol condensed ricinoleate in the oil phase.

2. The tofu coagulant of claim 1, wherein the concentration of magnesium chloride hexahydrate in the aqueous phase is 50 to 70% by mass, the concentration of polyglycerol condensed ricinoleate in the oil phase is 6 to 20% by mass, and the ratio of aqueous phase / oil phase is 60 / 40 to 75 / 25.

3. 3. A method for producing tofu, comprising using the tofu coagulant according to claim 1 or 2.

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