JP2013074803A - Method for producing gallate-type catechin-containing tofu - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a tofu that has a reduced grassy smell and a smooth texture free from rough touch in spite of containing a gallate-type catechin and soybean protein.SOLUTION: The method for producing a gallate-type catechin-containing tofu is characterized in that the amount of the gallate-type catechin is 0.6-5.0 wt.% based on raw material soybean, and n that soybean milk, obtained by mixing the gallate-type catechin with raw material soybean at a production stage before the raw material soybean is ground, is used as a raw material.

Description

  The present invention relates to a method for producing tofu with reduced blue odor containing gallate catechins.

  Tofu, a processed soybean food familiar to Japan, is rich in high-quality protein, unsaturated fatty acids, vitamins and minerals, and has recently been consumed not only in Japan but also in the US and Asia. It is food.

  Furthermore, recently, physiological functions such as prevention of osteoporosis by soy isoflavone, alleviation of unpleasant symptoms of menopause and prevention of arteriosclerosis are known, and it is one of the health foods that is attracting the most attention now. Nonetheless, tofu is a unique soy odor, making it a barrier to product choice for consumers who value preference over nutritional functionality, and reducing the unpleasant odor of tofu is very important. It has become a challenge.

  Therefore, as a method for masking the odor of soy milk as a raw material for tofu, for example, flavor improvement by adding palatinose (Patent Document 1), unpleasant odor reducing method by adding panose (Patent Document 2), taste improvement by perilla extract (Patent Literature 3), suppression of soybean milk odor by adding yeast extract (Patent Literature 4), and flavor improvement by grape skin extract (Patent Literature 5) have been proposed. However, none of these methods is practically sufficient because the odor masking effect is insufficient or the masking agent itself has a strong flavor.

  The unpleasant odor of tofu is composed of carbonyl compounds such as acetaldehyde, acetone, hexanal and ethyl vinyl ketone, alcohols such as hexanol, amines, phenols and fatty acids. Among them, n-hexanal (1-hexanal) and n-hexanol (1-hexanol), which are known as causative substances of blue odor, are the main causative substances of tofu unpleasant odor, and these reductions are important. It has become a challenge.

  On the other hand, regarding soybean products, low-odor natto using a catechin compound as a deodorizing component (Patent Document 6) and a preservative for tofu food using a catechin compound as an antibacterial component (Patent Document 7) have been proposed. However, these methods have been insufficient in reducing the blue odor of soybeans.

  Regarding the functionality of catechins, which are polyphenols abundant in green tea, not only the deodorizing and antibacterial effects as described above, but also physiological activities such as antioxidant action, cancer suppression action, cholesterol lowering action, inactivation of influenza virus, etc. Is expected.

  Among the catechins, various studies have revealed that gallate catechins having a galloyl group in the molecule, such as epicatechin gallate (ECg) and epigallocatechin gallate (EGCg), exhibit extremely high physiological activity. ing. For example, it has been reported that gallate-type catechins exhibit higher physiological activity than non-gallate-type catechins with respect to the growth inhibitory effect of human lung cancer cell lines, the inactivation of human influenza virus, the inhibitory effect on LDL oxidation, and the like. However, gallate-type catechin has a unique astringency expressed as astringent taste, and has a bitterness two to three times stronger than epicatechin (EC) and catechin (C). Mitigation of this is a very important issue.

  Furthermore, since gallate-type catechins react with proteins and aggregate and precipitate, it is difficult to add to products containing proteins. If soy milk containing such aggregates and precipitates is added to a coagulant or gelling agent If the tofu is made by adding the protein, the gelation of the protein will not be uniform, the texture will be rough and the original smooth texture will not be obtained. Therefore, the method of hydrolyzing gallate catechin by acting tannase has been taken (Patent Document 8).

  In addition, a method using a proteolytic peptide having an average molecular weight of less than 7,000 and a peptide or protein having a molecular weight of 7,000 or more in combination with catechins has been proposed (Patent Document 9). The effect of preventing aggregation precipitation was insufficient.

JP 2003-230365 A JP 2005-137362 A JP 2005-253348 A JP 2002-253163 A JP 2009-189356 A JP-A-8-173077 JP-A-3-65153 JP 2007-319008 A JP 2004-346132 A

  An object of the present invention is to provide a method for producing tofu having a smooth texture without roughness, although the blue odor is reduced and gallate catechin and soy protein are contained.

  In order to achieve the above-mentioned problems, the present inventors have conducted intensive research, and as a result, adjusted the amount of gallate catechin relative to the raw soybean, and in the tofu production process, added the gallate catechin before the raw soybean grinding step. When it was added, it was found that a tofu having a smooth texture without aggregation and roughness was obtained, and the present invention was completed.

That is, the gist of the present invention is as follows.
[1] A method for producing tofu containing gallate type catechin, wherein the amount of the gallate type catechin is 0.6 to 5.0% by weight with respect to the amount of raw material soybean, and the raw soybean is polished A method for producing tofu characterized by using soy milk obtained by mixing the gallate-type catechin with raw soybeans in the production stage before crushing,
[2] The method for producing tofu according to [1], wherein the gallate catechin is derived from a tea extract having a gallate catechin purity of 45% by weight or more.

  According to the present invention, there is no bitter astringency or tea taste even when gallate type catechin is added, and the blue odor of tofu due to n-hexanal and n-hexanol can be significantly reduced. In addition, since gallate catechin has high physiological activity, the tofu obtained by the present invention has a very high health promoting effect.

FIG. 1 shows a total ion chromatogram (TIC) obtained by solid phase microextraction-gas chromatograph mass spectrometry (SPME-GC-MS method) for tofu obtained in Comparative Example 1 and Example 1 performed in Test Example 1. ).

Hereinafter, the present invention will be described in more detail.
The term “tofu” as used in the present invention refers to all the raw soybeans added with a coagulant or gelling agent to soy milk and coagulated.

The method for producing tofu is divided into the following steps (1) to (5).
(1) A process in which raw soybeans are soaked in water for a certain period of time (swelling process)
(2) Process of grinding swollen raw material soybeans with a mixer (grinding process)
(3) The process of adding water to the ground soybeans and heating (heating process)
(4) A step of filtering the heat-treated product with a filter cloth or the like and separating it into okara and soy milk (filtering step)
(5) A process in which soy milk is placed in a coagulation container and a coagulant or gelling agent is added to coagulate (coagulation process)

  And in this invention, it is obtained by mixing the said gallate type catechin in the stage before said (2) grinding process, ie, a stage until it grind | pulverizes a swelling process or the raw material soybeans swollen with a mixer etc. In soymilk, protein aggregation / precipitation is remarkably reduced, making it possible to produce tofu with a smooth texture without roughness, despite containing gallate catechins and soy protein.

  Specific examples of the method of adding the gallate catechin to the raw material soybean include a method of adding the raw material soybean in the immersion water, adding it after being immersed in water, and adding it immediately before the grinding step. .

  On the other hand, when gallate catechin is added and mixed in the (3) heating step, (4) filtration step, and soy milk obtained after filtration, aggregation and precipitation occur in the soy milk in any case.

Moreover, in this invention, it is adjusted so that the quantity of gallate catechin may be 0.6 to 5.0 weight% with respect to the quantity of the said raw material soybean, and the blue smell of the tofu obtained becomes notable Can be reduced. When the amount of the gallate catechin is less than 0.6% by weight, the effect derived from the gallate catechin that reduces the blue odor of tofu cannot be sufficiently obtained, and when it exceeds 5.0% by weight, the gallate catechin is not obtained. I strongly feel the bitter taste. The amount of the gallate catechin is preferably 1.0 to 3.0% by weight.
The amount of gallate catechin relative to the amount of raw material soybean indicates the weight of gallate catechin when the soybean (dry weight) used as the raw material is 100% by weight.

  The raw material soybean used in the present invention is not particularly limited as to its production area and variety.

In the present invention, the “gallate catechin” is a catechin having a galloyl group in the molecule, and specifically refers to ECg, EGCg, Cg (catechin gallate), GCg (gallocatechin gallate) and the like. These may be purified products, crude products, natural products containing these, or processed products thereof, but it is preferable to use a tea extract of 45% by weight or more as the purity of gallate catechins. . The purity of the gallate catechin is more preferably 60% by weight or more, and still more preferably 90% by weight or more. Examples of such commercial products of gallate type catechin include Taiyo Kagaku Co., Ltd. “Sunphenon”, Mitsui Norin Co., Ltd. “Polyphenone”, and the like.
In the present invention, by using a tea extract having a gallate catechin purity of 45% by weight or more, not only the masking effect is sufficient, but also the tea flavor is suppressed and the tofu flavor is improved.
The tea extract (tea extract) refers to a product mainly composed of catechins obtained from tea leaves. Specifically, from tea made from leaves of Camellia (Camellia spp.), Extracted with water, acidic aqueous solution, aqueous ethanol, ethanol, aqueous methanol, methanol, acetone, ethyl acetate or aqueous glycerin solution at room temperature, warm temperature or heat It was obtained from what was done.

Further, in the present invention, in the tofu, if desired, an antifoaming agent, a polysaccharide thickener, a sugar, a fruit juice, a vegetable juice, teas, coffee, alcohols, a sour agent, carbon dioxide gas, a fragrance, a coloring agent, You may add arbitrary components, such as dietary fiber, vitamins, minerals, an amino acid, fats and oils, an emulsifier, and a high sweetness degree sweetener (artificial sweetener). By appropriately selecting these optional components, the range of palatability of the tofu obtained can be expanded.
The said arbitrary component should just be used in the range which does not have a bad influence on palatability and physical stability.
In addition, what is necessary is just to add the said arbitrary component in the arbitrary steps of the manufacturing process of said (1)-(5).

Moreover, the immersion time and temperature of the raw material soybean in water in the (1) immersion step,
(2) Kind of mixer in grinding process, temperature at grinding, soybean state after grinding,
In the (3) heating step, the quantitative ratio of ground soybean and water, heating temperature and heating time,
For each condition such as the size and shape of the soymilk coagulation container in the (4) filtration step, the type of filter cloth, the squeezing force in the temperature filtration, and the temperature in the (5) coagulation step. There is no particular limitation as long as it is the same as the tofu production conditions.

  In addition, as the coagulant used in the (5) coagulation step, organic acids such as bittern (magnesium chloride), bran powder (calcium sulfate), glucono delta lactone (GDL), calcium chloride, magnesium sulfate, citric acid, Examples of the transglutaminase and the gelling agent include gelatin, agar, carrageenan, pectin, and starch.

  Moreover, what is necessary is just to give a well-known process for the process after the said (5) coagulation | solidification process according to the kind of desired tofus, such as silken tofu, cotton tofu, and filling tofu.

  As described above, it is possible to efficiently produce a tofu having a smooth texture without roughness, although the blue odor is reduced and the gallate catechin and soy protein are contained.

  In addition, the tofu obtained in the present invention can be easily processed into frozen tofu, cancer, deep-fried, deep-fried, tofu hamburger and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the description of the following examples, “part” means part by weight.

(Comparative Example 1)
20 parts of soybean were immersed in 80 parts of water overnight at room temperature to swell. Subsequently, the whole amount was ground with a mixer, 40 parts of water was added, 0.4 part of an antifoaming agent (trade name: Creton Power, manufactured by Kao Corporation) was added, and the mixture was heated at 80 ° C. for 1 hour. . Thereafter, the squeezed and filtered portion was removed using a filter cloth to obtain 100 parts of soy milk. The obtained soymilk was cooled to room temperature, and a solution obtained by dissolving 0.3 part of a coagulant (trade name: Fuji Glucon, manufactured by Fuso Chemical Industry Co., Ltd.) in 5 parts of water was added and mixed. The mixed solution was filled and sealed in a plastic container and heated at 90 ° C. for 30 minutes to obtain filled tofu. The obtained tofu had a uniform fine texture and had a smooth texture, but was a tofu with a blue odor peculiar to soybeans.

Example 1
20 parts of soybeans are soaked overnight at room temperature in 80 parts of water in which 0.4 parts of tea extract (trade name: Sanphenon 90S, gallate type catechin purity 66% by weight, manufactured by Taiyo Kagaku Co., Ltd., the same shall apply hereinafter) is dissolved. And swollen. Subsequently, the whole amount was ground with a mixer, 40 parts of water was added, 0.4 part of an antifoaming agent (trade name: Creton Power, manufactured by Kao Corporation) was added, and the mixture was heated at 80 ° C. for 1 hour. . Thereafter, the squeezed and filtered portion was removed using a filter cloth to obtain 100 parts of soy milk. Filled tofu was obtained from the obtained soy milk in the same manner as in Comparative Example 1. The obtained tofu had no blue odor or bitter taste, formed a uniform fine texture, and had a smooth texture.

(Example 2)
20 parts of soybean were immersed in 80 parts of water overnight at room temperature to swell. Subsequently, 0.4 part of tea extract was added and mixed, the whole amount was ground with a mixer, 40 parts of water was added, and the mixture was heated at 80 ° C. for 1 hour. Thereafter, the squeezed and filtered portion was removed using a filter cloth to obtain 100 parts of soy milk. Filled tofu was obtained from the obtained soy milk in the same manner as in Comparative Example 1. The obtained tofu had no blue odor or bitter taste, formed a uniform fine texture, and had a smooth texture.

(Comparative Example 2)
20 parts of soybean were immersed in 80 parts of water overnight at room temperature to swell. Subsequently, the entire amount was ground with a mixer, and then 0.4 part of tea extract was added and mixed, 40 parts of water was added, and the mixture was heated at 80 ° C. for 1 hour. Thereafter, the squeezed and filtered portion was removed using a filter cloth to obtain 100 parts of soy milk. Filled tofu was obtained from the obtained soy milk in the same manner as in Comparative Example 1. The tofu thus obtained had a uniform and fine texture and had a smooth texture but had a blue odor. .

(Comparative Example 3)
20 parts of soybean were immersed in 80 parts of water overnight at room temperature to swell. Subsequently, the entire amount was ground with a mixer, 40 parts of water was added, and the mixture was heated at 80 ° C. for 1 hour. Thereafter, when 0.4 part of tea extract was added and mixed, aggregation / precipitation occurred in the mixture. Subsequently, the obtained mixture was squeezed and filtered using a filter cloth to remove the residue and obtain 100 parts of soy milk. The obtained soy milk was light in color, and did not coagulate even in the same manner as in Comparative Example 1, and did not become tofu.

(Comparative Example 4)
The soy milk obtained in Comparative Example 1 was cooled to room temperature, and a mixture of 0.3 part of a coagulant (trade name: Fuji Glucon, manufactured by Fuso Chemical Co., Ltd.) in 5 parts of water was added and mixed with 100 parts of soy milk. Subsequently, 0.4 part of tea extract was added and mixed with 4 parts of water. Aggregation then occurred. The mixed solution was filled and sealed in a plastic container and heated at 90 ° C. for 30 minutes to obtain filled tofu, but the obtained tofu was not uniform and protein aggregation was partially observed.

[Test Example 1]
Each sample (tofu) obtained in Comparative Example 1 and Example 1 was analyzed by solid phase microextraction-gas chromatograph mass spectrometry (SPME-GC-MS method) shown below. FIG. 1 shows a comparison of the obtained total ion chromatogram (TIC). The ionic strength of each chromatogram is set so that 1.3 × 10 ⁸ is 100%. Each peak is the following component.
Retention time: component << 5:21 >>: n-hexanal << 10:08 >>: 2-pentylfuran << 14:03 >>: n-hexanol << 16:43 >>: 1-octen-3-ol

  From FIG. 1, it can be confirmed that the peaks of n-hexanal and n-hexanol are clearly reduced in Example 1 (No. 2) compared to Comparative Example 1 (No. 1).

  Subsequently, 1.0 ppm of cyclohexanone as an internal standard substance was added to each sample (tofu) of Comparative Examples 1 and 2 and Examples 1 and 2, and analysis was performed according to the following analysis method. Based on the peak area value of the internal standard substance in the obtained chromatogram, n-hexanal and n-hexanol were quantified from each peak area value. The amount of each component was evaluated by a relative value when the value of Comparative Example 1 was 100. The results are shown in Table 1.

<Analysis method>
Measurement method: Sample 4.00 ± 0.04 g was finely crushed, collected in a headspace vial (20 mL capacity), and sealed with a cap with a septum. Next, SPME fiber was put into the head space portion of the vial bottle to extract volatile components. Thereafter, the SPME fiber was put into the sample inlet of the GC-MS meter, the extraction component was introduced into the capillary column, and mass spectrometry was performed.

SPME conditions: Fiber (50/30 μm, DVB / CAR / PDMS, manufactured by Spelco), preheating (65 ° C., 3 minutes), adsorption time (30 minutes), desorption time (5 minutes), inlet temperature (250 ℃)
GC-MS conditions: GC-MS meter (JMS-Q1000GC K9, manufactured by JEOL Ltd.), column (Inter-cap WAX, 0.25 mmid × 30 m, film thickness 0.25 μm, manufactured by GL Sciences), temperature condition ( 5 minutes at 40 ° C. → 230 ° C. 5 minutes / minute → 230 ° C. for 5 minutes), split (ratio: 5.6), carrier gas (helium)

[Test Example 2]
A sensory test of soybean odor (blue odor) was conducted by five panelists. The results obtained by the sensory evaluation method shown below are shown in Table 1.
<Sensory evaluation method>
Five panelists evaluate the intensity of soybean odor according to the contents shown below in three stages, and the average value is rounded off and expressed as an integer.
Strength: Content 1: Little soy odor is felt.
2: A soybean odor is felt.
3: Strongly felt soy odor.

From the results shown in Table 1, in the tofu obtained in Examples 1 and 2, the amounts of n-hexanal and n-hexanol, which are blue odor components, are significantly reduced compared to those in Comparative Example 1. I understand that. This result coincides with the sensory evaluation result, and it is understood that the soybean odor is reduced by the reduction of the blue odor component. From these results, it can be said that it is effective to add gallate-type catechins at a stage before grinding raw material soybeans in order to reduce soybean odor.
Moreover, from the results of Comparative Examples 3 and 4, it can be seen that addition of gallate catechins after grinding causes aggregation of soybean protein.

Claims (2)

  A method for producing tofu containing gallate catechins, wherein the amount of gallate catechins is 0.6 to 5.0% by weight based on the amount of raw soybeans, and before the raw soybeans are ground A method for producing tofu characterized by using, as a raw material, soy milk obtained by mixing the gallate-type catechin with a raw material soybean in the production step.   The method for producing tofu according to claim 1, wherein the gallate catechin is derived from a tea extract having a gallate catechin purity of 45% by weight or more.

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