JPH0448417B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a soybean processing method. More specifically, it provides soybean cotyledons with improved flavor and color tone and high NSI (protein water solubility index), including isolated soybean protein, polysaccharides, oligosaccharides, soybean milk, textured or fibrous, etc. The present invention provides soybean cotyledons that are excellent as raw materials for protein foods. (Prior Art) Many methods have been known for peeling soybeans as raw materials for tofu and the like. Among them, methods for heating and peeling soybeans include, for example,
84644, 58−71858, 59−147647, 59−150550, 59
-150661 etc. The main difference between the present invention and the prior art is that the present invention removes moisture from soybeans in the process of sorting, heating drying, splitting them into two, peeling, and sieving to obtain soybean cotyledons.
The surface of the soybeans is evenly heated and dried by adjusting the soybean temperature to 70 to 80℃, making it easier to molt and remove the hypocotyls, generate less fine powder (grips), and increase the The aim is to obtain high yields of soybean cotyledons that retain NSI. (Problems to be Solved by the Invention) Soybeans are composed of skin, hypocotyls, and cotyledons, and dust and the like adhere to the skin, which deteriorates the color tone and flavor of soybean products (products obtained using soybeans). In addition, the hypocotyl contains a large amount of saponin and polyphenol compounds, which deteriorate the flavor of soybean products. Therefore, the present inventors aimed to remove these soybean hulls and soybean hypocotyls to obtain soybean cotyledons that have improved flavor and color and retain high NSI. In line with the above purpose, soybeans were split into two, and attempts were made to molt the soybean and remove the hypocotyl. However, (a) it is difficult to split into two and remove the skin, (b) finely pulverized parts (grits) are likely to occur due to splitting, (c) it is difficult to separate the hypocotyl and cotyledons, and ( d) Dehulling to keep the NSI of soybean cotyledon protein high
I encountered a problem in which it was difficult to set the conditions for removing hypocotyl. (Means for solving the problem) Conditions for obtaining soybean cotyledons by sorting raw soybeans, splitting them into two using a splitting means such as a grinder, wind-selecting, removing the skin, and sieving to achieve the above purpose. While conducting various studies, we found that soybeans, which normally have a moisture content of about 12 to 15%, were adjusted in advance to below 12% moisture, and the temperature of the soybeans (actual temperature measured using a soybean thermometer) was By uniformly heating the soybeans in a relatively short period of time to 70-80℃, the surface of the soybeans can be dried uniformly, and the inside of the soybeans can be heated to a temperature at which the soybeans remain soft. It can be easily cracked and peeled, (b) finely pulverized parts (grits) are not easily generated even when split in two and sieved, (c) hypocotyls and cotyledons can be easily separated, and (d) split in half and sieved. The separated soybean cotyledon having some skin can be easily removed using a peeling means, and (e) the NSI of the soybean cotyledon protein that has been peeled off and dehulled and hypocotyl can be obtained. The present invention was completed based on the knowledge that it is possible to maintain a high temperature. That is, the present invention includes a process of adjusting the moisture content of soybeans to 12% or less, heating and drying the soybeans to a temperature of 70 to 80°C, and splitting the soybeans into two, and a process of peeling the split soybeans. This is a soybean processing method characterized by obtaining soybean cotyledons by combining the following. Known soybeans can be used as the soybeans used in the present invention. Normally, raw soybeans contain immature beans, impurities, etc., so it is preferable to sort them to make the particle size uniform, as this makes subsequent processing easier. As a method of sorting, known sorting means such as sieve sorting, roll sorting, wind sorting, density sorting, etc. can be used. The present invention involves a process of adjusting the moisture content of soybeans to 12% or less, a process of heating and drying the soybeans to a temperature of 70 to 80℃, and splitting the dried soybeans into two. It is characterized by combining the process of peeling the soybeans (if they contain some skin). The purpose can be achieved by such a combination. First, reduce the moisture content of soybeans to 12% or less (preferably 8 to 12%).
%, more preferably 10 to 11%). Normally, soybeans contain 12 to 15% moisture, so by slowly drying them at low temperatures (usually 60 to 70°C), the moisture content of soybeans can be adjusted to below 12%. A moisture content of 8 to 12% is suitable for compressing the harvested cotyledons to extract soybean oil. When the soybean moisture content is less than 8%, the resulting soybean cotyledons tend to crumble when pressed, which is not preferable. Soybeans already within this moisture range do not require moisture adjustment. In addition, it is preferable to adjust the moisture content of soybeans with a moisture content of less than 8% to 8 to 12% by over-humidifying the soybeans. Also, if the moisture content of soybeans exceeds 12%, splitting and peeling of the soybeans cannot be performed properly, which is undesirable. A known drying method can be used to adjust the soybean moisture content to 12% or less. For example, a ventilated vertical dryer,
Countercurrent multistage dryer, ventilation rotary dryer, etc. It tends to be preferable for the drying temperature to be relatively low (usually about 60 to 70°C) and the drying time to be relatively slow (usually about 30 to 60 minutes). Next, it is important to dry the soybeans whose moisture content has been adjusted to 12% or less so that the soybean temperature is 70 to 80°C. If the temperature of the soybean is less than 70°C, the heat drying and flexibility of the soybean will not be sufficient, and the generation of grits will increase in the next halving process, which will deteriorate the yield of soybean cotyledons, which is undesirable. Also, the temperature of soybeans
If the temperature exceeds 80°C, the NSI of the obtained soybean cotyledons decreases, which is not preferable. Soybeans with a temperature of 70 to 80°C have the appropriate flexibility to be broken into two, can be crushed with less grit, and can be easily removed.
This is suitable because it does not cause a decrease in NSI.
The moisture range in which soybeans maintain appropriate flexibility when heated to 70 to 80°C can be set at approximately 7 to 11%.
If the soybean is too dry, it tends to lose its flexibility when heated and increase the occurrence of grits during the halving process. Drying means suitable for maintaining the appropriate flexibility inside the soybean and uniformly drying the surface of the soybean include:
For example, fluidized bed drying, airbed drying, rotary kiln, etc. can be used. Among them, fluidized bed drying is the most suitable because it is suitable for uniform surface drying of soybeans. For example, the conditions for fluidized bed drying are usually a hot air temperature of 80°C.
°C to 90 °C, temperature inside the bed 75 °C to 85 °C, residence time 3 to 4
Approximately a minute is suitable, and the conditions can be changed as appropriate depending on the scale and purpose. Next, the soybeans that have been dried and have appropriate internal flexibility and surface brittleness are split into two. A known coarse crusher (for example, a grinder, a rubber roll, a cracking roll, etc.) can be used to divide the mixture into two. For example, when using a grinder, it is preferable to use a grinder with a grindstone spacing slightly wider than the soybean grain size. If a grinder with a grinding wheel spacing narrower than the soybean grain size is used, the soybean cannot be split into two properly, resulting in increased occurrence of grits and poor cotyledon yield. Moreover, if the distance between the grinding wheels is too wide, the amount of unbroken soybeans will increase, which is not preferable. For example, when splitting soybeans with a grain size of 6.5 mmφ into two, the appropriate distance between grinding wheels is about 7 mm. When splitting into two, it is preferable to prevent the temperature of the soybeans from dropping, and even if it does, it is preferably 50°C or higher. As the temperature drops, soybeans become harder and tend to crack into two, causing more grit. Once the temperature drops, soybeans tend to become hard and difficult to split in half and remove the skin, so it is better to heat them again. Further, when using a grinder, the generation of grit tends to be reduced when the rotation speed of the grindstone is relatively low. In addition, the soybeans that have been split into two are wind-selected and the skins are removed.
It is possible to repeatedly split the un-halved soybeans obtained by sieving (usually, about one episode occurs; if this does not occur, there is no need to split the soybeans into two again). Normally, it can be completely split into two by re-splitting process. Breaking into two can be done in the same way as the above-mentioned splitting of soybeans into two.
For example, when using a grinder, the grain size of unsplit soybeans is usually about 5 mm, so the distance between the grinding wheels of the grinder is preferably about 5.5 mm.
In addition, if the soybeans are to be split into two again, there is no need to separately heat and dry the unbroken soybeans. The soybean split in two can be wind-selected to remove the skin, if desired, and sieved to remove the hypocotyl and grits to obtain the soybean cotyledon. Normally, the soybean cotyledons that have been split into two and sieved often still have about 20% of the skin attached (based on the skin of the whole soybean).
It is preferable to cool the sieved soybean cotyledon to 40° C. or below (preferably 30° C. or below) and then peel and remove the skin using a peeling means. As the peeling means, known means such as a grinder, a peeling machine, and hand kneading can be used. When using a grinder, it is preferable that the distance between the grinding wheels be wider than the diameter of the soybean particles split into two. The peeling effect of the peeling means tends to increase as the soybean cotyledon containing the skin is cooled;
Below that, the peeling effect reaches approximately equilibrium. for example
From 60°C to 30°C, the peeling rate (weight ratio of peeled skin to whole soybean skin) tends to increase by about 8%. Note that known means such as left cooling, forced cooling (for example, mechanical means such as an oscillating draft cooler and a rotary draft cooler) can be used as the cooling means. As described above, the soybean cotyledon obtained by splitting the soybean into two, peeling, and dehulling/dehulling the hypocotyl contains almost no skin or hypocotyl, and can be used as a soybean cotyledon that meets the purpose. In addition, the skin removal after splitting in two and the skin removal after peeling are as follows:
Known means (eg, aspirator, wind classifier, etc.) can be used. In addition, a known sieving machine (for example, a rotary shifter, a vibrating sieve, etc.) can be used for sieving after the above-mentioned halving. The cotyledon obtained through the above process has a high yield (usually about 85% or more for soybean, 95% or more for soybean cotyledon), has improved flavor and color, and has an extremely low degree of denaturation, so it is NSI (usually less than about 2% decrease in NSI), isolated soy protein, polysaccharides, oligosaccharides,
It is excellent as a raw material for protein foods such as soy milk, textured or fibrous protein foods. (Example) Embodiments of the present invention will be described below with reference to Examples. Example 1 American soybeans (moisture 12%) were sorted using a sieve with a mesh size of 4.8 x 12 mm, and the average particle size was 6.6 mm.
Soybeans of φ (particle size 5.4 to 8.4 mmφ) were obtained. Pre-drying the sorted soybeans (30 minutes with hot air at 70℃)
The moisture content was adjusted to 11%. 5000 parts by weight (hereinafter referred to as "parts") of soybeans with a moisture content of 11% were heated with hot air at a speed of 3.4 m/cm using an experimental fluidized bed dryer.
sec, heated and dried under the conditions shown in Table 1,
Grinder for immediate tofu production (Kurihara Iron Works Co., Ltd.)
It was divided into two pieces with a grindstone spacing of 7 mm using a grinding wheel (manufactured by J.D. Co., Ltd.), and the skin was removed using a wind classifier (wind speed of 3 to 5 m/sec).
part), use a 4.3 x 19 mm sieve to sieve and separate the unhalved soybeans (500 parts), and separate the soybeans with a grinding wheel spacing of 5.5 mm.
The soybeans were split into two again using a mm grinder, and the skin was removed in the same way (39 parts) to obtain split soybeans. Split soybeans were separated into cotyledons (4422 parts), hypocotyl parts and grit parts (total 250 parts) using an 8-mesh sieve.
). The cotyledon part was cooled to 30℃ using an aspirator, passed through the grinder again (7 mm distance between grinding wheels), screened and sieved to remove the skin part (66 parts) and grit part (24 parts), resulting in 4324 parts of the cotyledon part. won. Dehulling rate of soybean, hypocotyl removal rate, and obtained cotyledon part
NSI is shown in Table-1.

[Table] However, (A) is the heating drying temperature (heating time was 3 minutes), (B) is the soybean product temperature, (C) is the soybean dehulling rate *1, and (D) is the hypocotyl removal rate * 2. (E) represents NSI*2. Also, *1: Soybean hull removal rate (%) = 100 x (weight of remaining soybean hulls in the product) / (weight of sorted soybeans x 0.08)
(Calculated assuming the percentage of soybean hulls is 8%.) *2: De-hypocotyl rate (%) = 100 x (weight of residual soybean hull hypocotyl in product) / (weight of sorted soybeans x 0.025)
(The ratio of soybean hypocotyl was calculated as 2.5%.) *3: NSI is the ratio (%) of water-soluble protein to total protein, and was determined by a known measurement method. Application example 1 4000 parts by weight of the cotyledon obtained in the same manner as No. 5 of Example 1 was pressed, extracted twice with n-hexane (10 times) and air-dried to obtain a defatted cotyledon (residual oil content of approximately 0.5%). ) was adjusted. Add 10 times the amount of water to this defatted cotyledon and heat at 40°C.
After stirring and extracting the soymilk for 40 minutes and removing okara, the obtained soymilk was subjected to isoelectric precipitation (PH4.5) using hydrochloric acid, and the resulting curd was neutralized using caustic soda to make a 10% solution. UHT type high temperature instant sterilization (10 at 135℃
) and spray dried to obtain isolated soybean protein. Comparative Example 1 Soybeans were treated in the same manner as in Example 1 to prepare defatted soybeans, and in the same manner as in Example 1, isolated soybean protein was obtained. Experimental Example 1 Isolated soybean protein obtained in Example 1 and Comparative Example 1
A 10% solution of each of the isolated soybean proteins obtained in the above was prepared, and a panel of 10 people tested the flavor, etc. The results are shown in Table-2.

[Table] However, A is the isolated soybean protein of Example 1, and B is the isolated soybean protein of Comparative Example 1. Application example 2 20% by weight of defatted cotyledons obtained in the same manner as application example 1
using an experimental twin-screw extruder at a screw rotation speed of 570 R.PM and a barrel temperature of 170°C.
It was extruded through a die (5 mmφ) to obtain a textured protein with an excellent fibrous structure. Next, the defatted soybean used in Comparative Example 1 was treated in the same manner to obtain a textured protein with an excellent fibrous structure. After soaking each obtained tissue protein in hot water and draining the water,
Flavor etc. were tested by 10 panelists. The results are shown in Table-3.

[Table] However, A is the textured protein of defatted soybean cotyledons, and B is the textured protein of defatted soybean. (Effects) As detailed above, the present invention makes it possible to obtain soybean cotyledons with improved flavor and color tone and high NSI at a high yield. Furthermore, soybean cotyledons, which are excellent raw materials for protein foods such as isolated soybean protein, polysaccharides, oligosaccharides, soymilk, and textured or fibrous products, can be used to (a) easily split and peel soybeans; (b) Finely pulverized parts (grits) are difficult to form, (c)
This enables a method of molting and removing hypocotyl that facilitates the separation of hypocotyls and cotyledons. Although soybean dehulling is generally effective by aging the soybean, the present invention does not require any special aging. As explained above, the present invention greatly contributes to the development of industry.

Claims (1)

[Claims] 1. Adjusting the moisture content of soybeans to 12% or less, heating and drying the soybeans to a temperature of 70 to 80°C, and splitting the soybeans into two, and peeling the split soybeans. A soybean processing method characterized by obtaining soybean cotyledons by combining steps. 2. The aspect of splitting into two is that soybeans that have been dried to a temperature of 70 to 80°C are put through a grinder with a grindstone spacing wider than the soybean grain size.
Soybean processing method described in section. 3 The method of peeling is to cut the soybeans into two at 30°C.
The method for treating soybeans according to claim 1 or 2, wherein the soybean is cooled and then peeled using a peeling means. 4. The soybean processing method according to claim 1, in which the unhulled soybean that has been split into two and sieved is split into two again.