Preparation process of soybean extract.

1. Introduction

Soybean extract has become a very important substance in many different areas. It is rich in various valuable components such as isoflavones and proteins, which make it highly applicable in the food, pharmaceutical, and cosmetic industries. The preparation of soybean extract is a complex process that requires careful attention to each step to ensure the quality and effectiveness of the final product.

2. Selection of Raw Materials

2.1 Quality Criteria

• The first step in the preparation of soybean extract is the careful selection of high - quality soybeans as raw materials. High - quality soybeans should be free from mold, pests, and other contaminants.
• They should also have a consistent size and shape, which can indicate their maturity and quality.
• The variety of soybeans is also crucial. Different varieties may have different levels of active components. For example, some varieties are known to be rich in isoflavones, while others may have a higher protein content.

• Soybeans are usually sourced from reliable suppliers. These suppliers should follow good agricultural practices to ensure the quality of the soybeans.
• Some large - scale production may even require soybeans to be sourced from specific regions known for their high - quality soybean production, such as certain areas in the United States or China.

3. Cleaning of Soybeans

3.1 Purpose of Cleaning

• Once the soybeans are selected, they need to be cleaned thoroughly. The main purpose of cleaning is to remove any impurities that may be present on the surface of the soybeans.
• These impurities can include dirt, stones, and plant debris. If not removed, these impurities can affect the quality of the extract and may also damage the equipment used in the subsequent processing steps.

• One common method of cleaning soybeans is by using a mechanical cleaner. This type of cleaner uses screens and air blowers to separate the soybeans from larger impurities such as stones and smaller impurities such as dust.
• Another method is washing. However, washing needs to be carefully controlled to avoid excessive moisture absorption by the soybeans, as too much moisture can lead to spoilage or mold growth.

4. Crushing of Soybeans

4.1 Importance of Crushing

• After cleaning, the soybeans are crushed into a fine powder. Crushing is an important step as it increases the surface area of the soybeans, which in turn facilitates the extraction of the active components in the subsequent step.
• A larger surface area allows the extraction solvents to come into better contact with the soybean components, leading to more efficient extraction.

• There are several types of equipment that can be used for crushing soybeans. One common type is the grinder. Grinders can be adjusted to produce different particle sizes of the soybean powder.
• Another option is the mill. Mills are often used in large - scale production and can crush a large quantity of soybeans at once.

5. Extraction of Active Components

5.1 Selection of Extraction Solvents

• Once the soybeans are crushed into powder, extraction solvents are used to extract the active components. Commonly used solvents include ethanol and hexane.
• Ethanol is a popular choice because it is relatively safe, has a good solubility for many of the active components in soybeans, and is also acceptable for use in the food and pharmaceutical industries in certain concentrations.
• Hexane, on the other hand, is often used for its excellent ability to extract lipids. However, it is more flammable and requires more careful handling.

• The crushed soybean powder is mixed with the extraction solvent in a suitable container. The ratio of soybean powder to solvent is carefully controlled to ensure optimal extraction.
• The mixture is then stirred or agitated for a certain period of time. This helps to ensure that all parts of the soybean powder are in contact with the solvent and that the active components are effectively extracted.
• The extraction process may be carried out at a specific temperature. For example, a slightly elevated temperature may sometimes be used to increase the solubility of the active components and speed up the extraction process, but this also needs to be carefully controlled to avoid degradation of the components.

6. Filtration

6.1 Purpose of Filtration

• After the extraction process, the next step is filtration. Filtration is carried out to separate the extract (which contains the active components) from the solid residues (such as the remaining soybean fiber).
• By removing the solid residues, a cleaner and more pure extract can be obtained, which is essential for the subsequent steps of concentration and purification.

• There are several filtration methods available. One common method is using a filter paper in a funnel. This is suitable for small - scale laboratory - level filtration.
• For larger - scale production, more advanced filtration equipment such as filter presses or membrane filters may be used. Filter presses can handle larger volumes of the extract - residue mixture and can effectively separate the solid and liquid phases.

7. Concentration and Purification

7.1 Concentration

• After filtration, the extract may still contain a large amount of solvent. Concentration is carried out to reduce the amount of solvent in the extract, thereby increasing the concentration of the active components.
• One common method of concentration is evaporation. Evaporation can be carried out under reduced pressure to lower the boiling point of the solvent and speed up the process. This helps to preserve the integrity of the active components as they are less likely to be degraded at lower temperatures.

• Purification is the final step in obtaining a high - quality soybean extract. The purpose of purification is to further remove any impurities or unwanted components from the extract.
• There are several purification methods available. One method is chromatography. Chromatography can separate different components in the extract based on their different chemical properties, such as their affinity for a particular stationary phase.
• Another method is crystallization. Crystallization can be used to purify components that can be crystallized out of the extract. This method is often used for purifying isoflavones or proteins in soybean extract.

8. Conclusion

In conclusion, the preparation of soybean extract is a multi - step process that involves careful selection of raw materials, cleaning, crushing, extraction, filtration, concentration, and purification. Each step is crucial in ensuring the quality and effectiveness of the final soybean extract. With the increasing demand for soybean extract in various industries, it is important to continuously optimize these processes to produce high - quality extracts with a high content of desired components such as isoflavones and proteins.

FAQ:

1. What are the main criteria for selecting high - quality soybeans as raw materials?

When selecting high - quality soybeans for soybean extract production, factors such as the absence of mold, a high protein content, and a normal appearance are considered. Soybeans should be free from physical damage and signs of disease. The variety of soybeans also plays a role, as some varieties may have higher levels of the desired components like isoflavones.

2. Why are ethanol or hexane commonly used as extraction solvents?

Ethanol and hexane are commonly used as extraction solvents because they have good solubility properties. Ethanol is a polar solvent and can effectively extract polar components such as isoflavones. Hexane, on the other hand, is a non - polar solvent, which is suitable for extracting non - polar substances in soybeans. Their chemical properties allow them to selectively dissolve the active components from the soybean powder during the extraction process.

3. How is the filtration process carried out in the preparation of soybean extract?

Filtration in the preparation of soybean extract can be achieved through various methods. One common method is using filter papers or filter membranes. The extract - solid residue mixture is passed through the filter medium. The pores of the filter are small enough to retain the solid residues while allowing the liquid extract to pass through, thus separating the two components.

4. What are the typical methods for concentration and purification of soybean extract?

For concentration, methods like rotary evaporation are often used. This involves reducing the volume of the extract by evaporating the solvent under reduced pressure at a controlled temperature. Purification can be done through chromatography techniques. For example, column chromatography can separate different components based on their differential adsorption to the stationary phase in the column, allowing for the isolation of the desired components in a purer form.

5. How are the isoflavones or proteins in soybean extract beneficial in the food industry?

In the food industry, isoflavones in soybean extract can act as antioxidants, which can help prevent the oxidation of food products and extend their shelf life. Proteins can be used as a source of nutrition, for example, in the production of protein - enriched foods. They can also contribute to the texture and functionality of food products, such as improving the emulsifying and gelling properties.

Related literature

• Preparation and Characterization of Soybean Extracts Rich in Isoflavones"
• "Optimization of the Extraction Process of Soybean Proteins"
• "Soybean Extract: A Promising Ingredient in Cosmetics"