JPS6057822B2 - Method for producing soybean flour from which odor components have been removed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing soybean flour from which unpleasant odor and bitter taste are removed.

When soybean protein is used as food, its unique unpleasant odor and bitterness limit its use.

This unpleasant odor and bitter components (hereinafter referred to as odor components).
) has been proposed in the past, but one way to indicate the degree of denaturation of soybean protein is to use NSI (
While maintaining the quality of soybean-containing components such as fat and protein to meet the intended use without reducing the NitrogenSolubilityIndex (percentage of soluble nitrogen to total nitrogen), soybeans from which odor components have been removed can be used for industrial purposes as protein products. The conventional method for removing odor components is to heat-treat raw soybeans or powdered soybean flour with dry heat. Methods such as steam treatment and methods of extracting and removing odor components using hydrophilic solvents such as alcohol or non-hydrophilic solvents such as benzene are known.

However, when odor components are removed by dry heat or steam treatment, proteins are denatured due to excessive treatment and NS
This is unavoidable since the I value decreases, and even in the method using the above-mentioned solvent, the treatment temperature, the time, and the temperature at which the solvent attached to the soybeans is finally evaporated and removed,
There were drawbacks such as the NSI value decreasing with time. The present invention has improved these drawbacks, and uses soybean flour obtained by dehulling and pulverizing raw soybeans as a raw material, adding alcohol or an alcohol aqueous solution to this, stirring and mixing it to form a slurry. , reduce pressure and heat to evaporate and remove low-boiling components and evaporate odor components together with alcohol and water to obtain soybean flour from which odor components have been substantially removed, while removing moisture and odor contained in the evaporation condensate. It is characterized by removing components, increasing the purity of alcohol, and reusing it.

Further, according to the above treatment, the NSI value of the soybean flour from which odor components have been removed is not substantially lowered.

In this evaporation step, in order to avoid protein denaturation, it is desirable to complete the process at as low a temperature as possible and in a short time. In the present invention, in order to promote evaporation at temperatures below 100°C, the pressure is reduced and the evaporated vapor is transferred to an indirect cooling type exchanger (hereinafter referred to as a condenser).

), cooled and condensed, and recovered as a condensate. This condensate has alcohol as its main component, and also contains water and odor components. Normally, the raw soybean flour contains moisture derived from the moisture content in the raw soybean and moisture absorbed during the powdering process, and the amount thereof is about 5 to 8% by weight. When the above treatment is performed using alcohol, a portion of this water is azeotroped with the alcohol and transferred to the condensate.

The odor components also evaporate together with the alcohol or water, and a portion of the odor components migrates into the condensate, while the remainder does not condense in the condenser and is discharged from a vacuum generating device such as a vacuum pump together with non-condensable gases. Therefore, if the alcohol recovered as a condensate is repeatedly used as raw alcohol, the purity of the alcohol will gradually decrease and the moisture and odor components will increase, resulting in a decrease in the odor component removal effect. Furthermore, since the price of alcohol is higher than that of soybean flour, it is necessary to recover alcohol at a high yield and reuse it for industrial use. FIG. 1 shows a process diagram of the present invention.

The raw soybean flour is made by dehulling and crushing raw soybeans.
Although a drying step is performed as necessary to ensure efficient dehulling and pulverization, the raw soybean flour usually contains 5 to 8% by weight of water. As the raw alcohol, ethanol with a purity of 95% by weight or more (water content of 5% by weight or less) is initially used. After mixing and stirring the two to form a uniform slurry, the container is heated and depressurized to evaporate the ethanol content. It is simple and reliable to use a container with a sealed structure equipped with a stirrer whose walls can be heated with a heating medium and perform the above treatment in a batch manner, but it is also possible to carry out continuous treatment using a continuous extraction dryer. can. The evaporated vapor is directed to a condenser where most of the ethanol and water and some of the odor components are condensed. The non-condensable gas containing the remainder of the odor components is discharged from a vacuum generating device such as a vacuum pump to maintain the internal pressure of the container and condenser at a reduced pressure. The soybean flour from which the ethanol content has been evaporated is taken out from the container, cooled and sieved as needed to produce a product. In the soybean flour of this product, odor components have been substantially removed, and the NSI value is not substantially lower than that of the raw soybean flour. The condensed and recovered alcohol contains ethanol, water, and odor components, so it is sent to an alcohol purification equipment.
Improves the purity of ethanol by removing moisture and odor components.

FIG. 2 shows an example of an alcohol purification apparatus.

Water substantially free of ethanol is taken out from the bottom 12 of the distillation column 11, and an aqueous ethanol solution with a purity of 90% or more is taken out from the top 13. Among the odor components, the high boiling point components are taken out together with the water at the bottom 12 of the column, and the low boiling point components are discharged from the top 13 of the column. Separate.

14 is a condensate, 15 is a cooling water vibrator, 16 is a non-condensable gas, 17 is a vacuum pump, 18 is a purified alcohol tank,
19 is a condensed and recovered alcohol supply pipe, 20 is a heating steam pipe, and 21 is a waste water tank.

In this way, an aqueous ethanol solution with a purity of 90% or more and a low content of odor components can be recovered as purified alcohol. The purified alcohol is then reused as raw alcohol. FIG. 4 shows a process diagram for carrying out the present invention, in which 41 is a jacketed stirring dryer, 42 is an electric motor with a speed reducer, 50 is a product soybean flour hopper, 44 is a condenser, 4
8 is a condensation recovery alcohol tank, 11 is a distillation column, 14 is a condenser, 21 is a waste water tank, and 18 is a purified alcohol tank.

Examples are shown below.

Example 1 200y1 raw soybean powder was obtained by dehulling and pulverizing American soybeans, and 180cc of ethanol with a purity of 99.5% or higher was used as raw material alcohol, and the volume was 100ml as shown in Figure 3.
Mixing and stirring to form a slurry, evaporation drying, and recovery of condensed alcohol 38 were carried out using an apparatus mainly consisting of a 0 cc jacketed kneader 31 and a condenser 34.

The product soybean flour obtained under the following operating conditions had no raw odor or bitter taste, had a pale yellow color, and was of good quality. The following table shows a comparison of the quality values of raw soybean flour, product soybean flour, raw alcohol, and condensed recovered alcohol. The product soybean flour had excellent properties for food use, with no decrease in useful components such as protein and lipids, and high percentages of water-soluble protein and NS* values. In addition, 30 is a steam vibrator,
32 is an electric motor with a speed reducer, 35 is a cooling water pipe, 37 is an asvilator, and 38 is a condensed recovery alcohol.

Operating conditions: Kneader internal pressure, temperature: 10) Rr, 4O~45 Condenser cooling water temperature: 10°C Time from start of evaporation to end point: 4
Powder Comparison Example 1 The alcohol condensed and recovered in Example 1 was used repeatedly as the raw material alcohol, and the raw soybean powder was new each time; the quality of the product soybean flour and condensed recovered alcohol obtained in the 8th time was as follows. It was hot on the street.

Example 2 The condensed recovered alcohol obtained in Comparative Example 1 was
0W! 77! , purified using the distillation apparatus shown in Figure 2, mainly consisting of a glass distillation column with 27 plates, to a water content of 9% by weight.
, purified alcohol with an ethanol content of 91% by weight was obtained.

Raw soybean flour was treated with this purified alcohol in the manner described in Example 1 to obtain a product soybean flour of good quality and pale yellow with no odor or bitterness. The analysis value of the product soybean flour is 3.6% moisture.
, protein 39.7%, water soluble protein 30.8%, NSI
The value was 7.8%. As shown in the above examples, by the method of the present invention, high-quality product soybean flour from which odor components have been removed can be produced on an industrial scale without using alcohol to lower the NSI value of soybean protein. .

[Brief explanation of the drawing]

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are process diagrams for implementing the present invention. 11... Distillation column, 14... Condenser, 18
...Purified alcohol tank, 1911-I condensed and recovered alcohol supply pipe, 31 ... Jacketed seconder, 34 ... Condenser, 41 ... Jacketed stirring dryer , 44... condenser, 48...
... Condensate recovery alcohol tank, 50 ... Product soybean flour hopper.

Claims (1)

[Claims] 1. Soybean flour slurried with alcohol or alcohol aqueous solution is dried under reduced pressure to obtain soybean flour from which odor components have been removed, while water evaporated under reduced pressure and alcohol containing odor components are cooled and condensed and recovered as a condensate. A method for producing soybean flour from which odor components have been removed, characterized in that the water and odor components contained in the condensate are purified and removed, the alcohol purity of the condensate is increased, and then the condensate is reused.