How to make smooth, high-protein soy milk

Abstract

A method for manufacturing smooth, high-protein soy milk includes a soybean cutting step, a peeling step, a grinding and extraction step, and a cooking step. In the cutting step, soybean raw materials are divided and chopped into small pieces, which include coarse pieces that cannot pass through a 5-mesh sieve and fine pieces that can pass through. The total amount of the small pieces is 100 wt%, with the coarse pieces comprising 70 to 90 wt% and the fine pieces comprising 10 to 30 wt%. The small pieces are then peeled by removing the soybean skin and degassed to obtain peeled small pieces. In the grinding and extraction step, the peeled small pieces are ground with grinding water and subjected to a first centrifugation to remove residue, obtaining soy juice. In the cooking step, the soy juice is heated to obtain soy milk. The soy milk has a protein content greater than or equal to 5.5 g / 100 ml and a smooth texture and excellent flavor.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing soy milk, and more particularly to a method for manufacturing a smooth, high-protein soy milk. [Previous Technology]

[0002] In recent years, due to the increased demand for protein intake among sports and fitness groups, consumers are looking for soy milk drinks that are high in protein and taste good.

[0003] The traditional soybean milk production process typically involves washing, soaking, grinding, boiling, and removing residue to prepare the soy milk, using a water-to-soybean ratio to control the concentration. However, high-concentration soy milk has poor extraction efficiency, and higher protein concentrations, coupled with stringent sterilization conditions, can lead to protein precipitation, denaturation, or increased viscosity in packaged soy milk products after sterilization, negatively impacting the taste. While using food additives such as phosphates can increase protein stability, it can also negatively affect food safety perceptions. [Summary of the Invention]

[0004] Therefore, the object of the present invention is to provide a method for manufacturing a smooth, high-protein soy milk that can improve upon at least one of the aforementioned disadvantages.

[0005] Therefore, the method for manufacturing smooth, high-protein soy milk of the present invention includes a soybean cutting step, a peeling step, a grinding and extraction step, and a boiling step.

[0006] In the cutting step, a soybean raw material is divided and chopped into a crushed soybean raw material, which includes a coarse crushed soybean portion that cannot pass through a 5-mesh sieve and a fine crushed soybean portion that passes through a 5-mesh sieve.

[0007] The total amount of the crushed bean raw material is 100wt%, the content of the coarse crushed bean part is 70 to 90wt%, and the content of the fine crushed bean part is 10 to 30wt%.

[0008] In the peeling step, the soybean raw material is peeled by removing the soybean skin and de-peeling by vacuuming to obtain peeled soybeans. In the grinding and extraction step, the peeled soybeans and a grinding solution are ground in a grinding device and centrifuged to obtain soybean juice. In the boiling step, the soybean juice is heated to obtain soy milk, the soy milk having a protein content greater than or equal to 5.5g / 100ml.

[0009] The advantages of this invention are: by controlling the particle size and coarseness ratio of the crushed soybean raw material and peeling the crushed soybean raw material, the grinding and extraction efficiency of protein can be improved, and soy milk with a protein content of more than 5.5g / 100ml, smooth taste and good flavor can be obtained without the use of food additives.

Implementation Method

[0010] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0011] Referring to Figure 1, an embodiment of the method for manufacturing smooth, high-protein soy milk of the present invention includes a soybean cutting step S1, a peeling step S2, a grinding and extraction step S3, a boiling step S4, a degassing step S5, a cooling step S6, and a sterilization step S7.

[0012] In the soybean cutting step S1, a soybean raw material is fed into a cutting machine to be divided and chopped, and the degree of breakage is controlled by screening to obtain a crushed soybean raw material. The crushed soybean raw material includes a coarse crushed soybean portion that cannot pass through a 5-mesh sieve, and a fine crushed soybean portion that passes through a 5-mesh sieve. With the total amount of the crushed soybean raw material being 100wt%, the content of the coarse crushed soybean portion is 70~90wt%, and the content of the fine crushed soybean portion is 10~30wt%. In this embodiment, the soybean is yellow soybean.

[0013] In the peeling step S2, the soybean skin of the crushed soybean raw material is peeled off and the soybean skin is removed by vacuuming to obtain a peeled crushed soybean.

[0014] In the grinding and extraction step S3, the peeled soybeans and a grinding solution enter a grinding device. The peeled soybeans and the grinding solution are sequentially coarsely ground and finely ground, then centrifuged to remove residue, obtaining soybean juice and a first soybean residue. The first soybean residue is discharged from the grinding device and enters a mixing device. The first soybean residue is stirred and mixed with hot water continuously flowing into the mixing device, then centrifuged to remove residue, obtaining a second soybean residue and the grinding solution. The second soybean residue is discharged and discarded, while the grinding solution enters the grinding device to grind the peeled soybeans. The temperature of the grinding solution is 75 to 85°C. The ratio of soybean raw material to grinding solution is in the range of 1:4.6 to 1:5.4, which is beneficial to the grinding and extraction efficiency, obtaining a better soybean juice concentration, and maintaining a smooth texture while avoiding an increase in viscosity while maintaining a high protein content. Specifically, the ratio of soybean raw material to grinding solution is 1:5.

[0015] It should be noted that the peeled and crushed soybeans and the grinding water are continuously fed into the grinding device, while the hot water and the first soybean residue are continuously fed into the mixing device. At the beginning of the production process, the hot water has not yet been mixed with the first soybean residue; the grinding water is simply the hot water. As the first soybean residue begins to enter the mixing device, the hot water begins to extract the residual protein from the first soybean residue, thus becoming the grinding water containing protein. As the protein content of the grinding water gradually increases, the protein content of the soybean juice also increases accordingly.

[0016] In the boiling step S4, steam is directly injected into the soy milk to heat the soy milk to 110~120℃ and maintain it for 1~2 minutes to obtain soy milk.

[0017] In the degassing step S5, the heated soy milk is degassed under reduced pressure to remove excess beany smell from the soy milk.

[0018] In the cooling step S6, the degassed soy milk is cooled.

[0019] In the sterilization step S7, the cooled soy milk is heated and sterilized at 130 to 140°C for a few seconds.

[0020] The soy milk products of Examples 1 and 2 prepared by the manufacturing method of the present invention are shown in Table 1. The difference lies in the heating temperature of the soy milk. The heating temperature of the soy milk in Example 1 is 120°C, and the heating temperature of the soy milk in Example 2 is 110°C. Furthermore, the protein content of both Examples 1 and 2 is greater than or equal to 5.5g / 100ml. Specifically, the protein content of Examples 1 and 2 is 5.8g / 100ml.

[0021] Data from Comparative Examples 1-6 are summarized in Tables 2 and 3. The difference between Comparative Example 1 and Example 1 is that the grinding water temperature is lower, and the soybean raw material is directly subjected to the grinding and extraction step S3 without being crushed in the soybean cutting step S1 or peeled in the peeling step S2. The difference between Comparative Example 2 and Example 1 is that the soybean raw material is directly ground without being crushed in the soybean cutting step S1 or peeled in the peeling step S2. The difference between Comparative Example 3 and Example 1 is that the content of coarsely crushed soybeans screened in the soybean cutting step S1 is lower. The difference between Comparative Example 4 and Example 1 is that the grinding water temperature is lower. The difference between Comparative Example 5 and Examples 1 and 2 is that the grinding water temperature is lower and the heating temperature of the soybean juice in the boiling step S4 is higher. The difference between Comparative Example 6 and Example 1 is that the heating method of the soybean juice in the boiling step S4 is different (heating is performed in a boiling tank), the heating temperature of the soybean juice is slightly lower, but the heating time of the soybean juice is longer.

[0022] Among them, the sugar content was measured using an ATAGO digital custom sugar content meter. The protein content was measured using a Kjeldahl nitrogen analyzer. The viscosity was measured using a Brookfield viscometer with rod #1 at 30 rpm. Centrifugal stability was determined by observing the sedimentation state at the bottom of the centrifuge tube at 2,500 rpm for 5 minutes; the lower the value, the higher the centrifugal stability. The drinking experience was evaluated by a panel of 10 people, who evaluated the bean flavor, oil flavor, richness, smoothness, and overall liking. The scores were out of 5, with 1 being the worst and 5 being the best.

[0023] Table 1 Example 1 2 Peeling yes yes Coarsely ground bean content (wt%) 70~90 70~90 How to heat soy milk Steam injection Steam injection Heating temperature of soy milk (°C) 120 110 Soy milk heating time (min) 1~2 1~2 Grinding ratio of soybeans to water 1:5 1:5 Grinding water temperature (°C) 75~85 75~85 Sugar content (°bx) 13.4 13.4 Ph value 6.67 6.70 Viscosity (cps) 10~30 10~30 Protein content (g / 100ml) 5.8 5.8 Centrifugal stability <0.1 <0.1 bean flavor 4 4 Oil flavor 2 2 Intense 4 4 Smoothness 5 5 Overall Preference 5 5

[0024] Table 2 Comparative example 1 2 3 Peeling none none yes Coarsely ground bean content (wt%) Unbroken beans Unbroken beans 50~70 How to heat soy milk Steam injection Steam injection Steam injection Heating temperature of soy milk (°C) 110 110 110 Soy milk heating time (min) 1~2 1~2 1~2 Grinding ratio of soybeans to water 1:5 1:5 1:5 Grinding water temperature (°C) 50 75~85 75~85 Sugar content (°bx) 12.1 12.4 12.6 Ph value 6.65 6.60 6.65 Viscosity (cps) 60~100 30~60 10~30 Protein content (g / 100ml) 5.2 5.3 5.4 Centrifugal stability >0.3 0.1~0.2 <0.1 bean flavor 3 3 4 Oil flavor 3 2 2 Intense 3 4 3 Smoothness 2 4 5 Overall Preference 2 3 4

[0025] Table 3 Comparative example 4 5 6 Peeling yes yes yes Coarsely ground bean content (wt%) 70~90 70~90 70~90 How to heat soy milk Steam injection Steam injection Boiling Pot Heating temperature of soy milk (°C) 110 125 105 Soy milk heating time (min) 1~2 1~2 3~5 Grinding ratio of soybeans to water 1:5 1:5 1:5 Grinding water temperature (°C) 70 70 75~85 Sugar content (°bx) 13.0 13.0 13.3 Ph value 6.61 6.61 6.61 Viscosity (cps) 10~30 10~30 >100 Protein content (g / 100ml) 5.6 5.3 5.7 Centrifugal stability 0.1~0.2 <0.1 0.1~0.2 bean flavor 4 3 3 Oil flavor 5 2 3 Intense 3 4 4 Smoothness 4 4 2 Overall Preference 2 4 3

[0026] Referring to Table 1, in Examples 1 and 2, the content of coarsely broken soybeans that cannot pass through a 5-mesh sieve is controlled to be between 70 and 90 wt%, which is beneficial for subsequent grinding and improves protein extraction efficiency. This is because excessively finely divided soybeans or fine powder are removed during the peeling and degassing process in the peeling step S2 and do not enter the grinding system, resulting in protein loss. Insufficiently divided soybeans with larger particles have soybean skins that are difficult to peel off, and the remaining soybean skins reduce grinding extraction efficiency and affect the taste. Furthermore, since the grinding water extracts the protein from the first soybean residue, it can further increase the protein content of the ground soybean juice.

[0027] Furthermore, grinding soybeans with high-temperature grinding water can avoid the enzymatic action of soybeans and reduce the oily flavor of the soy milk. In the soy milk production process, the purpose of boiling the soy milk is to inactivate enzymes (such as lipoxygenase) and destroy factors that negatively affect absorption (such as trypsin inhibitors), thereby improving protein utilization. At the same time, the boiling process reduces the microbial content, preventing the soy milk from developing off-flavors due to oxidation or becoming rancid due to microbial action. Therefore, using direct steam injection to rapidly and directly heat the soy milk at high temperatures for a short time can reduce protein denaturation and reduce the dilution of the soy milk by condensed steam, thus preventing a decrease in protein content and increasing the protein content to 5.8g / 100ml.

[0028] The short heating process can also avoid damaging the protein structure, thereby reducing the viscosity of the soy milk and improving its smoothness. This results in the soy milk having a lower oil flavor in the evaluation, and achieving better scores in terms of richness, smoothness, and overall likability.

[0029] Referring to Tables 2 to 3, the differences between Comparative Examples 1 to 6 and Examples 1 and 2 are explained below.

[0030] The soybean raw material of Comparative Example 1 was not peeled and the grinding water temperature was low, resulting in poor protein extraction and low content, and the viscosity was high, resulting in low smoothness.

[0031] The soybean raw material of Comparative Example 2 was not dehulled. Although its viscosity was lower than that of Comparative Example 1, it was still higher than that of Examples 1 and 2, and its protein content was also lower. This is because the main function of soybean seed coat is to protect soybeans, and its main component is fiber, which does not help with grinding and extracting protein, thereby reducing the protein extraction rate.

[0032] The coarse bean content of Comparative Example 3 is 50-70%. The low proportion indicates that the proportion of fine bean content is high. In the fine bean content, the finely broken beans and fine powder will be removed during the degassing process, resulting in protein loss. Therefore, the protein content still cannot reach 5.5g / 100ml.

[0033] The grinding water temperature of Comparative Example 4 was relatively low, which led to an increase in the enzyme activity of the soy milk, which greatly increased the oil flavor and seriously affected the drinking experience.

[0034] The steam heating temperature of Comparative Example 5 is relatively high, meaning that more steam needs to be injected to reach the required temperature. At this point, steam condensation will produce more water that enters the soy milk, thus diluting its concentration. Furthermore, excessively high boiling temperatures can significantly affect or damage the protein structure, thereby affecting the detection of protein in the soy milk. Therefore, the protein content of Comparative Example 5 is low.

[0035] Comparative Example 6 heats the soy milk indirectly by means of a boiling pot. The heating and cooling time is longer, resulting in a longer overall heating time. This causes the protein to undergo a long heat treatment process, which causes greater damage to the tertiary structure of the protein, leading to protein denaturation and increased viscosity, thus reducing the smoothness of the texture.

[0036] In summary, the method for manufacturing smooth, high-protein soy milk of the present invention, by controlling the particle size and coarse-to-fine ratio of crushed soybean raw materials and peeling the crushed soybean raw materials, can improve the grinding and extraction efficiency of protein. Soy milk with a protein content of more than 5.5g / 100ml and a smooth taste and good flavor can be obtained without the use of food additives, thus achieving the purpose of the present invention.

[0037] However, the above description is only an embodiment of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the scope of the patent application and the contents of the patent specification of the present invention shall still fall within the scope of the patent of the present invention. [Simplified Explanation of the Diagram]

[0038] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the figures, wherein: Figure 1 is a flowchart of an embodiment of the method for manufacturing smooth, high-protein soy milk of the present invention.

Claims

1. A method for manufacturing a smooth, high-protein soy milk, comprising: a soybean cutting step, wherein a soybean raw material is divided and chopped into a chopped soybean raw material, the chopped soybean raw material comprising a coarse chopped soybean portion that cannot pass through a 5-mesh sieve and a fine chopped soybean portion that passes through a 5-mesh sieve, wherein the total amount of the chopped soybean raw material is 100wt%, the content of the coarse chopped soybean portion is 70 to 90wt%, and the content of the fine chopped soybean portion is 10 to 30wt%; and a peeling step, wherein the chopped soybean raw material is subjected to soybean skin peeling and deskinning by vacuuming to obtain a peeled chopped soybean. The process includes a grinding and extraction step in which peeled soybeans and ground soybean water are ground in a grinding device and centrifuged to obtain soybean juice. The ratio of soybean raw material to ground soybean water is between 1:4.6 and 1:5.4, and the temperature of ground soybean water is between 75 and 85°C. The process also includes a boiling step in which steam is directly injected into the soybean juice to heat it to 110-120°C and maintain it for 1 to 2 minutes to obtain soy milk. The soy milk has a protein content of ≥5.5g / 100ml.

2. The method for manufacturing smooth, high-protein soy milk as described in claim 1, wherein, The viscosity of this soy milk is 10~30 cps.

3. The method for manufacturing smooth, high-protein soy milk as described in claim 1, wherein in the grinding and extraction step, a first soybean residue is obtained, the first soybean residue is mixed with a heated mixing device and centrifuged to remove residue to obtain grinding water, the grinding water is introduced into the grinding device and ground with the peeled and crushed soybeans.

4. The method for manufacturing smooth, high-protein soy milk as described in claim 1, wherein, Following the boiling step, the process includes a degassing step, a cooling step, and a sterilization step. In the degassing step, the soy milk is degassed under reduced pressure. In the cooling step, the soy milk is cooled. In the sterilization step, the soy milk is heated to 130 to 140°C.

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