JPH0257908B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for fractionating soybean components containing water extraction residues. Soybean consists of seed coat, cotyledons and hypocotyl parts. In the production of many soybean products, such as tofu, soymilk drinks, isolated soybean proteins, etc., the soluble portion of cotyledons is primarily used, and water extraction residues are inevitably produced as a by-product. In order to collect the water-soluble part of the cotyledons, except in the case of soybean processing at the manual stage or when producing extremely high value-added processed products, high-quality soybeans are carefully selected and completely dehulled as a pretreatment. Since this is not generally adopted due to cost, the water-extracted residue usually contains a mixture of components derived from the seed coat, cotyledons, and hypocotyl. This water-extracted residue has attracted attention for its physical properties such as water absorption and dispersibility derived from its porous structure, as well as its health and nutritional value as it is rich in coarse grains and protein components that remain uneluted. has been proposed for use. However, there are difficulties in using the water-extracted residue containing the three components mentioned above for these purposes, and the current situation is that a considerable portion is still used for feed with little added value. That is, of the three components mentioned above, those derived from the seed coat and hypocotyl have a rough or rough texture, and are inferior in water absorption and whiteness compared to the parts derived from cotyledons, making them unattractive. . Only the water-extracted residue derived from cotyledons is suitable for human consumption and has high utility value, but if other parts are mixed, there are problems with human consumption and the function of additives. Even if an attempt is made to separate the water-extracted residue consisting of the above-mentioned mixed components into the cotyledon-derived part and other parts by applying acceleration under the aqueous system, the seed coat-derived part is rigid and difficult to break, while the hypocotyl-derived part is brittle. Because it is easily broken when heated, it is deposited in three layers, starting from the upper layer: the seed coat-derived part, the cotyledon-derived part, and the hypocotyl-derived part, and separating only the middle layer requires a significant decrease in yield.
Another disadvantage is that it requires manual operation, or one has to settle for removing only the part derived from the seed coat. Regarding the part derived from the seed coat, we take advantage of the above-mentioned rigidity and resistance to breakage.
There is a known method of classifying and removing the unbroken seed coat components by crushing or grinding, using a wet or dry method.
With this method, it is difficult to remove the brittle hypocotyl-derived portion, and some of the seed coat-derived portions are also broken and mixed in, so it is difficult to adopt this method as a method for collecting only the cotyledon-derived portion. The present inventor has developed a selective, efficient, and industrially advantageous method for extracting a cotyledon-derived portion, which is suitable for human consumption and has high utility value, from a water-extracted residue containing a cotyledon-derived portion and other components. While conducting various studies on the separation of soybeans, we decided to use a screw conveyor-type centrifugal dewatering machine, which was conventionally known as a dehydrator or a filtration machine with relatively low accuracy, and of course had not been used as a treatment machine for water-extracted soybean residue. He discovered that the use of a machine was surprisingly extremely effective, and was able to complete this invention. The gist of this invention is to process an aqueous slurry of soybean ingredients containing water extraction residue with a screw conveyor type centrifugal dehydrator and separate the water extraction residue in the slurry into a cake side and a desorbed slurry side. This invention is a method for fractionating soybean components, and the present invention will be explained in detail below. In this invention, the water-extracted residue contains a cotyledon-derived portion and other components, ie, a seed coat or hypocotyl-derived portion, and the aqueous slurry may contain a water-soluble portion of the cotyledon. Aqueous extraction of soybeans or defatted soybeans is usually uneconomical in that one extraction is insufficient and a large amount of soluble components remain in the raffinate; on the other hand, it is uneconomical to extract virtually all soluble components. Preparing an aqueous slurry by adding water to the hardened extraction residue will unnecessarily increase the number of steps, so the aqueous slurry used in this invention is prepared in multiple stages (multiple times), usually 2 to 3 stages (multiple times). , is preferably an extracted slurry of . Conventionally, there was a method that required a crushing or grinding process for the purpose of removing seed coat components from mixed water extraction residues, but in this invention, a special crushing process is required to fractionate a specific water extraction residue. It is not necessary, and in fact, it is better not to perform any special crushing or grinding extraction in order to avoid contamination with partially crushed seed coat-derived components and hypocotyl-derived components. Therefore, it is a preferred embodiment that the aqueous slurry of soybean ingredients used in the present invention is a multistage (times) stirring extraction slurry of flaked soybeans or defatted soybeans. Here, flake-like particles generally have a particle size of 0.5 mm or more at 70% or more, and the particle size distribution becomes somewhat smaller during stirring and extraction. In the screw conveyor type centrifugal dewatering machine, the screen basket and the screw conveyor are arranged concentrically with a slight clearance, and the dewatered (deslurry) cake remaining on the screen basket is given a slight rotation difference from the basket. The screen basket and the screw conveyor may be either conical or cylindrical, and may be either vertical or horizontal. This device was previously known to have low fractionation accuracy when used as a filter, but this invention marks the first time that this device has been used to fractionate the water-extracted residue of soybeans. Moreover, it is surprising that a portion with high added value in the water extraction residue can be selectively and efficiently fractionated. In general, when similar equipment and methods are used, there is a negative correlation between the yield and selectivity of the fractionated target product, but when using a screw conveyor type centrifugal dehydrator, there is a negative correlation between the yield and selectivity of the fractionated target product. The precision or yield is superior to the same yield or the same fractionation precision of the fractionation method. This device also has the secondary effect of reducing the cost of dehydrating and drying the soybean water extraction residue. In other words, a decanter is conventionally used as an industrial method for removing residue from an extraction slurry, and the moisture content of the residue separated by a decanter is usually in the range of 83 to 86%, so dehydration and drying are necessary to obtain a dry product for storage. Although the cost was high, this device separates a portion of the residue as a low-moisture cake, significantly reducing dehydration and drying costs. As mentioned above, when similar devices and methods are used, there is generally a negative relationship between the yield and selectivity of the fractionation target. In this invention, the screen opening is 0.35 mm or less. Screen opening, yield (dry weight ratio of the water extracted residue in the desorption slurry to the water extracted residue contained in the aqueous slurry), and the weight ratio of the water extracted residue in the cake using a two-extraction stirred slurry of defatted soybean flakes. Some of the experimental results regarding the relationship with moisture are shown in Figure 1. Of these, the water extraction residue in the desorption slurry can be judged to be suitable for human consumption and has high utility value when the aperture diameter is large. 0.3mm, 0.2mm,
It is fractionated at 0.1mm, and the quality is
The one fractionated at 0.1 mm was the best, and the one fractionated at 0.4 mm was unsatisfactory in terms of quality.
On the other hand, the dehydration efficiency decreases as the opening diameter becomes smaller, but even with an opening diameter of 0.1 mm, when processing with a decanter (as mentioned above, it is usually
Since the moisture content can be reduced by about 5% (from 86% moisture), subsequent drying costs can be reduced. By the way, the effect of reducing water content by about 5% is
This is equivalent to saving 162 KCal of latent heat of vaporization per 1 kg of defatted soybeans processed. In this invention, the aqueous slurry of soybean ingredients is a stirred extraction slurry of flaked soybeans or defatted soybeans, and the most preferable range for fractionating the water extraction residue with the best quality is the fractionated cake side. The ratio of the water extraction residue on the desorption slurry side to the water extraction residue on the desorption slurry side is 50:
50 to 70 to 30, which varies somewhat depending on the clearance between the screw conveyor and the screen basket, but can be achieved when selecting a screen with an opening of approximately 0.08 to 0.25 mm. can. Although many types of sieving devices are known, devices other than the screw conveyor type have the disadvantage of maintaining a constant thickness of the layer of extraction residue that accumulates on the screen. The residue layer itself functions as a kind of sieve, and as a result, the quality of the desorbed slurry is inconsistent and clogging occurs, making it unsuitable for large-scale processing and making continuous operation difficult. . The screw conveyor type dewatering machine does not have such difficulties and can be operated without any problems when the clearance between the screen basket and the screw conveyor is in the range of 0.2 to 0.5 mm. The desorption slurry separated from the cake side by a screw conveyor type centrifugal dehydrator is then separated from the aqueous extraction residue by any known method for separating residue from an aqueous extraction slurry of soybean. This method can also be used. As mentioned above, the aqueous slurry provided to the screw conveyor type centrifugal dehydrator in the present invention is preferably a multi-stage (times) extraction slurry, and the dewatering slurry from the dehydrator contains recoverable water. Since it contains a soluble portion, the liquid portion separated from the residue at this stage can be combined with the soymilk that is the previous (round) extraction liquid to become a part of soymilk. The water extraction residue obtained by this invention is divided into two parts: the cake side is mainly suitable for feed (cows prefer dry soybean water extraction residue), and the other is suitable for human consumption. It has excellent whiteness and physical properties, and can achieve effective use of resources as a whole. The water-extracted residue of any fraction can be freely subjected to processes such as drying, pulverization, and sterilization depending on the final use purpose. This invention will be explained below with reference to Examples. Example: Add 700 kg of water to 100 kg of low-denatured defatted soybean flakes (80% or more of particles with a particle size of 0.5 mm or more), perform the first stage of extraction by stirring at 50°C for 10 minutes at pH 7.0, and mix soy milk with a decanter. It was separated into a water extraction residue. Furthermore, 500 kg of water was added to this water extraction residue,
The second stage of agitation extraction was performed under the same conditions, and the aqueous slurry was processed using a conical horizontal screw conveyor type dehydrator (product name: "Contavex" model H400) (screen opening 0.1 mm, clearance 0.3
mm, winding angle 720℃, 600G) and separated into the cake side and the desorption slurry (cake weight 85Kg, moisture 79%),
The desorption slurry is processed in a decanter and soy milk 380
Kg and a water extraction residue (weight 67 Kg, moisture 85%). As Comparison 1, a 2-extraction slurry obtained in the same manner as in Example was treated in a decanter and separated into 350 kg of soymilk and a water extraction residue (weight 180 kg, moisture 85%). As comparison 2, low modified defatted soybean flour (particle size 0.5mm
When the above (20% or less) was treated in the same manner as in the example, the weight of the cake side was 60 kg, and the weight of the water-extracted residue on the desorption slurry side was 90 kg. The water extraction residues separated from the desorption slurry of this example and comparison 2, and the water extraction residue of comparison 1,
The L value was measured using a color difference meter for each powder that was pulverized with a pulperizer with a diameter of 1.0 mm and dried to a moisture content of 5 to 6%, and the powder that was added with 4.5 times as much water as shown in the table below. As a result of visual observation, the product according to this example had no distribution of black or brownish spots, and was clearly superior in whiteness. On the other hand, in Comparison 2, spots were observed, and the product of Comparison 1 was the most inferior in appearance.

[Table] The above powder products were also measured by their water retention capacity (according to the measurement method stipulated in the "Japan Agricultural Standards for Vegetable Proteins and Seasoned Vegetable Proteins"), and the results shown in the table below were obtained. It was clear that the material was superior in terms of yield and physical properties.

【table】 [Brief explanation of drawings]

Figure 1 shows the screen opening diameter and the proportion of water extraction residue fractionated from the aqueous slurry into the desorption slurry when an aqueous slurry containing soybean water extraction residue is processed using a screw conveyor type centrifugal dehydrator. It is a graph showing the relationship between (dry matter weight percentage) and water content in the cake.

Claims (1)

[Claims] 1. Treating an aqueous slurry of soybean components containing water extraction residue with a screw conveyor type centrifugal dehydrator to separate the water extraction residue in the slurry into a cake side and a desorption slurry side. A method for fractionating soybean components, characterized by: 2. The fractionation method according to claim 1, wherein the aqueous slurry of soybean components is a multistage (times) stirring extraction slurry of flaky soybeans or defatted soybeans. 3. The fractionation method according to claim 1 or 2, wherein the opening of the dehydrator screen is 0.35 mm or less. 4. The fraction according to claim 3, wherein the ratio of the water extraction residue on the cake side separated by the dehydrator to the water extraction residue on the desorption slurry side is from 50:50 to 70:30 in terms of dry weight. Painting method. 5. The fractionation method according to claim 2, wherein the desorption slurry is separated into soy milk and water extraction residue.