JPS5921364A - Preparation of soybean or soybean protein having improved quality - Google Patents

Abstract

PURPOSE:To perpare soybean or soybean protein having improved quality, free from soybean smell and unagreeable odor and taste, by extracting soybean or soybean protein with a liquid obtained by the alkali- and active carbon-treatment of an alcohol-containing solvent used in extraction process. CONSTITUTION:Soybean or soybean protein is extracted with an alcohol-containing solvent to improve the quality of the soybean or the soybean protein. The circulation ethanol containing the components having unagreeable taste and odor is introduced through the line 1 into the thermal reactor 3, and an alkali is introduced through the line 2 into the reactor in the form of an aqueous solution. The amount of the alkali is >=0.1wt% based on ethanol. The mixture of the ethanol and alkali is mixed under heating at 40-82 deg.C to react a part of the ill-odor component with the alkali. After the completion of the reaction, the reaction solution is transferred to the concentrator 4, and distilled under atmospheric or reduced pressure. The concentrated residue is discharged from the outlet 5, and the ethanol vapor is condensed in the condenser 6. The condensed ethanol is passed through the active carbon adsorption column 7 to remove the remaining ill-odor component completely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the quality of plant seeds such as soybeans or defatted soybeans using an organic solvent extraction method. The present invention relates to a method for producing soybean protein that is free from soybean odor and off-flavor taste.

Recently, as the importance of plant proteins, particularly soybean proteins, as foods has increased, alcohol treatment of soybeans has been attracting attention and importance.

Conventionally, soybeans or defatted soybeans are mixed with methanol, ethanol,
It is well known that when brought into contact with hydrous lower alcohols such as propanol or organic solvents containing the above lower alcohols, the odor, flavor, and coloring substances peculiar to soybeans are extracted and removed, and the quality of the resulting soybean products is greatly improved. It is being

If this method is to be carried out industrially, it is economically necessary to distill and recover the solvent from the solvent attached to the soybeans and the used solvent and reuse it, but if the solvent is used repeatedly for a long period of time, it is necessary to use the simple distillation method. It cannot be removed. In addition, off-flavor and taste components that are different from the unpleasant odor peculiar to soybeans gradually accumulate in the solvent, and even if a product that is satisfactory in terms of the unpleasant odor, flavor, and color tone peculiar to soybeans is obtained, the above-mentioned off-odor and taste components are present in the final product. This will greatly reduce the commercial value of the product as a food product.

Various methods can be considered to prevent quality deterioration due to contamination of the circulating solvent, but there is no satisfactory method that simply and effectively prevents it.

There is a method of steam-treating the product (Japanese Unexamined Patent Publication No. 54-101456) to remove this off-flavor and taste component, but this method is not satisfactory in terms of the quality and cost of the soybean protein product, and another method is recycling. A method of increasing the specific volatility of odorous components by adding water to the alcohol used and separating them by distillation was considered (Japanese Patent Publication No. 56-36900), but this method is superior in that it can remove off-flavor components from the solvent. However, this method requires a complicated device and is not necessarily satisfactory in terms of cost, and a more economical and simple deodorizing method has been desired.

An object of the present invention is to provide a new method for easily and effectively removing trace amounts of off-flavor components from circulating alcohol and for producing and obtaining soybean protein products with excellent flavor.

As a result of various studies to achieve the above object, the present inventor found that (1) a step of adding 0.1% by weight or more of an alkali to the alcohol to an extraction-treated alcohol-containing solvent and heat-treating the same, and (2) an extraction process. It has been shown that off-flavor components can be separated and removed by extracting soybeans or soybean protein using an aqueous alcohol solution obtained by performing both steps of adsorbing the treated alcohol-containing solvent with activated carbon, regardless of their order. This discovery led to the completion of the present invention.

That is, the present invention is a method for producing soybeans or soybean protein products with improved quality, which is characterized in that off-flavor and taste components that accumulate in an alcohol-containing solvent subjected to extraction treatment are separated and removed by a combination of alkali treatment and activated carbon treatment. .

The method of the present invention will be explained by taking as an example a case where a soybean protein product is produced by treating defatted soybeans with ethanol. First, defatted soybeans are extracted with 40% to 99% by weight ethanol to remove the extracts. Ethanol is used for circulation after removing extracts by distillation etc. and adjusting the concentration. In addition, soybeans contaminated with solvent are treated to remove the solvent, the recovered ethanol is supplied for circulation, and the soybeans are ground into products with improved color and flavor.

The recycled ethanol recovered above looks colorless and transparent and has no difference from pure hydrated ethanol, but it contains an off-flavor component that is different from the soybean odor, and when soybeans are treated with this solvent, the soybean-specific odor Although the taste is improved, the off-flavor components in the solvent are adsorbed by the soybeans and remain in the final product, making it impossible to obtain a product with satisfactory quality.

As a result of intensive studies on this off-odor, the inventor of the present invention discovered that the off-odor is not the odor of a single component, but is an odor composed of multiple trace components, and furthermore, this odor can be broadly divided into irritating odor and putrid odor. It was discovered that the former are mainly aldehydes and esters, and the latter are amine-based substances.

The method of the present invention includes (1) a step of adding 0.1% or more of alkali to the alcohol and heat-treating the extracted alcohol-containing solvent in order to remove the irritating odor; and (2)
The process of adsorbing the extracted alcohol-containing solvent with activated carbon to remove the putrid odor is performed in any order to completely remove the off-flavor components in the alcohol aqueous solution.

First, the alkali treatment step uses an alkali such as sodium hydroxide, calcium hydroxide, potassium hydroxide, or an aqueous alkali solution thereof. The amount of alkali added is 0
．． 1% or more is preferable. If the amount is less than 0.1%, the effect of flavor improvement will not be observed much.

After adding the alkali, the mixture is heated to 40° C. to 82° C. and stirred to react the irritating odor components with the alkali. The reaction solution is preferably distilled to remove alkali and off-flavor components.

The amount of activated carbon used in the next activated carbon treatment step is preferably 5% or more based on the alcohol, and the activated carbon after use can be regenerated by a normal regeneration method and recycled.

Although no special equipment is required, an equipment as shown in Figure 1 is preferred. In Figure 1, A indicates alkali treatment and B indicates activated carbon treatment. Moreover, this process shows the same effect even if the order of ¥A¥ and ¥B¥ is changed.

In Figure 1, ¥1 is the ethanol supply port after distillation, ¥2 is the alkali supply port, ¥3 is the heating reactor, ¥4 is the evaporative concentrator, ¥5 is the concentration residue discharge port, 6 yen is a condenser, 7 yen is an activated carbon adsorption tower, and 8 yen is a purified ethanol outlet.

Circulating ethanol containing off-flavor components is supplied from the supply port ¥1 to the heating reactor at ¥3, and the alkali is supplied in an aqueous solution to the ethanol at a concentration of 0.1% by weight or more at the supply port ¥2.
Supplied from ¥. Furthermore, this mixed liquid is 40℃~82℃
The mixture is heated and stirred to cause some of the off-flavor components to react with the alkali.

After the reaction is completed, the reaction solution is supplied to the concentrator 4 and distilled under normal pressure or reduced pressure, the concentrated residue is discharged from the outlet, and the ethanol vapor is condensed in the condenser.

Next, the coagulated ethanol is fed to an activated carbon adsorption tower for 7 yen to completely remove the remaining off-flavor components. It is not necessary to purify the entire amount of ethanol for circulation; the proportion is determined depending on the required quality of the product.

Although the method for extracting defatted soybeans with ethanol has been described above, the present invention is applicable not only to defatted soybeans but also as a quality improvement method in the alcohol extraction treatment of plant seeds such as soybeans and soybean protein products manufactured using soybeans as raw materials. Ru. The most preferred alcohol is ethanol, but other lower alcohols such as methanol, propanol, and butanol can also be used.

The soybeans or soybean protein products obtained by the method of the present invention have a lower quality, whereas those obtained by the conventional method are contaminated with off-flavor components in ethanol and have inferior flavor and loss of commercial value. No off-odor taste was detected in the sensory tests of the product and circulating ethanol, indicating that the quality has been improved.

Example 1 Defatted soybean flakes (280 kg/hr) were subjected to continuous countercurrent extraction with 79 wt% ethanol solvent ratio 2 (560 kg/hr) at a temperature of 50°C. The obtained extracted ethanol miscella was concentrated in a concentrator under normal pressure, and the residue was collected at 72 kg/hr.
429 kg/hr of ethanol was obtained. Further, the soybean flakes containing the solvent were removed to obtain 218 kg/hr of flakes and 123 kg/hr of ethanol. The ethanol recovered from both processes was mixed and supplied to the next deodorizing process, but although this alcohol was clear and colorless, it contained components with off-flavors and tastes.

The recovered ethanol is first diluted with 0.5% of the ethanol solution.
% of sodium hydroxide 2.8 kg/hr and heating reaction vessel 3
The mixture was heated and stirred at 70° C. for 30 minutes.

The reaction solution was then concentrated in a concentrator under normal pressure, and 7.2 kg/hr of ethanol vapor as a residue was condensed in condenser 6 to obtain 548 kg/hr.

Although the pungent odor of this ethanol has disappeared, it still has an odor similar to putrid odor. The alkali-treated ethanol was then fed to the activated carbon adsorption tower 7 to obtain purified ethanol with no off-flavor or taste, and after adjusting the concentration to 79% by weight, it was recycled as an extraction solvent.

On the other hand, the recovered ethanol was recycled without being deodorized and purified, and the defatted soybeans were treated under the same conditions.

Expert panel 11 said that soybean flakes obtained by both methods were
A sensory test was conducted using a 5-point evaluation.

The results are shown in Table 1.

Table 1: Sensory test for soybean products (evaluation criteria: 0 points...5 points: no abnormal odor or taste...
・Extremely strong off-odor and taste) As shown in Table 1, products obtained using the conventional system that does not perform ethanol deodorization and purification clearly have residual off-odor and taste. It was an excellent product, with the odor and taste improved to the extent that it was almost unnoticeable.

Example 2 In Example 1, the following experiment was conducted for the purpose of examining the deodorizing effects of the first and second steps of the deodorizing process.

In Experiment A, only the first step of alkaline treatment was used in deodorizing purification. In Experiment B, only the first step of activated carbon treatment was used in deodorizing purification. In Experiment C, both steps of Example 1 were adopted, and in Experiment D. The extraction processing conditions and the like are the same as in Example 1 except that the order of both steps in C is reversed.

As shown in Table 2, a satisfactory soybean product could not be obtained by using each process alone, but a soybean product with improved off-flavor and taste was obtained by combining both processes even when the order was reversed.

Example 3 The following experiment was conducted for the purpose of investigating the influence of the amount of sodium hydroxide added in the alkali treatment step.

Extraction was performed according to the conditions of Example 1, and the recovered ethanol was extracted with sodium hydroxide at 0.02%, 0.05%, and 0.1%.
%, 0.5%, and 2%, and alkali treatment was performed at 70° C. for 30 minutes. The reaction solution was purified by distillation, then treated with activated carbon, and recycled for use.

About the soybean flakes obtained in the experiment at these 5 levels
A sensory test was conducted using point evaluation.

The results are shown in Table 3.

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Claims (1)

[Claims] In a method for improving the quality of soybeans or soybean protein by extracting soybeans or soybean protein with an alcohol-containing solvent, (1)
The steps of adding 0.1% or more of alkali to the alcohol to the extracted alcohol-containing solvent and heating it, and (2) adsorbing the extracted alcohol-containing solvent with activated carbon, are carried out in that order. 1. A method for producing soybeans or soybean protein with improved quality, which comprises extracting soybeans or soybean protein using an aqueous alcohol solution obtained by applying any of the following.