Preparation process of Tagetes erecta L. extract.

1. Introduction to Tagetes erecta L. (Marigold)

Marigold, scientifically known as Tagetes erecta L., is a well - known flowering plant. It is native to Mexico and Central America but has been widely cultivated around the world. Marigold is characterized by its bright - colored flowers, which can range from yellow to orange - red. It is not only a popular ornamental plant but also has significant economic value due to the various beneficial substances it contains.

2. Raw Material Collection

2.1. Selection of the Right Time

• The time of collection is crucial for obtaining high - quality marigold raw materials. Generally, it is best to harvest marigolds when the flowers are in full bloom. At this stage, the content of active substances in the flowers is relatively high.
• Harvesting too early may result in insufficient development of the flowers and lower content of target compounds, while harvesting too late may lead to the degradation or loss of some active substances.

• Hand - picking is a common method for collecting marigolds. This method allows for the selection of healthy and fully - developed flowers, ensuring the quality of the raw materials. However, it is a labor - intensive process, especially for large - scale cultivation.
• For commercial large - scale production, some mechanical harvesting methods may also be used. But special care must be taken to avoid damage to the flowers during the process.

3. Pretreatment of Raw Materials

3.1. Cleaning

• Once the marigolds are collected, the first step in pretreatment is cleaning. The flowers are usually washed with clean water to remove dirt, dust, and other impurities on the surface.
• Care should be taken during the cleaning process to avoid excessive mechanical damage to the flowers, as this may affect the subsequent extraction process.

• After cleaning, drying is an important step. Drying can be carried out using natural drying or artificial drying methods.
• Natural drying involves spreading the marigolds in a well - ventilated area, out of direct sunlight. This method is simple and cost - effective but may take a relatively long time and is affected by weather conditions.
• Artificial drying, such as using a drying oven, can control the drying temperature and humidity more accurately. A suitable drying temperature is usually around 40 - 60°C. Drying at too high a temperature may cause the destruction of some active substances.

• After drying, the marigolds are usually ground into a powder form. Grinding can increase the surface area of the raw materials, which is beneficial for the subsequent extraction process.
• The fineness of the powder should be controlled appropriately. Too coarse a powder may result in incomplete extraction, while too fine a powder may cause problems such as clogging during extraction.

4. Extraction Methods

4.1. Solvent Extraction

• Solvent extraction is one of the most traditional and widely used methods for Marigold Extract preparation.
• 4.1.1. Selection of Solvents
  • Common solvents used for Marigold Extraction include ethanol, hexane, and ethyl acetate. Ethanol is a popular choice due to its relatively low toxicity and good solubility for many active substances in marigolds.
  • The choice of solvent depends on the target compounds to be extracted. For example, if the aim is to extract carotenoids, hexane may be a more suitable solvent.
• 4.1.2. Operational Procedure
  • The dried and ground marigold powder is placed in a Soxhlet extractor or a similar extraction device. The solvent is then added to the extractor.
  • The extraction process usually involves continuous refluxing of the solvent for a certain period, which can range from several hours to days depending on the nature of the raw materials and the target compounds.
  • During the extraction, the solvent extracts the active substances from the marigold powder through a process of dissolution. Chemical reactions may occur depending on the nature of the substances and the solvent. For example, some polar solvents may interact with polar compounds in the marigold through hydrogen bonding.

• Enzymatic extraction is a relatively new and environmentally friendly method.
• 4.2.1. Enzyme Selection
  • Enzymes such as cellulase, pectinase, and protease can be used for Marigold Extraction. Cellulase can break down the cell walls of marigold cells, which are mainly composed of cellulose, making it easier for the active substances inside the cells to be released.
  • The selection of enzymes depends on the composition of the marigold cell walls and the nature of the target compounds. For example, if the cell walls contain a large amount of pectin, pectinase may be more effective.
• 4.2.2. Operational Procedure
  • The dried and ground marigold powder is mixed with the selected enzyme solution. The enzyme concentration, reaction temperature, and pH are important factors that need to be optimized.
  • Typically, the reaction is carried out at a relatively mild temperature (e.g., 30 - 50°C) and a specific pH range (e.g., pH 4 - 7). The reaction time may range from 1 - 3 hours.
  • During the enzymatic reaction, the enzymes break down the cell walls and other components of the marigold, releasing the active substances. This process is mainly a biochemical reaction, where the enzymes act as catalysts to accelerate the breakdown of specific components.

• Microwave - assisted extraction is a relatively fast and efficient method.
• 4.3.1. Principle
  • Microwaves can directly heat the polar molecules in the marigold raw materials. This rapid heating can cause the cell walls to rupture and the active substances to be released more quickly.
  • The microwave - induced heating is different from traditional heating methods. It is a volumetric heating process, which means that the entire sample is heated simultaneously rather than just the surface as in the case of traditional heating.
• 4.3.2. Operational Procedure
  • The dried and ground marigold powder is placed in a microwave - compatible extraction vessel. A suitable solvent is added to the vessel.
  • The microwave power, extraction time, and solvent - to - sample ratio are important parameters to be optimized. For example, a microwave power of 300 - 600 W and an extraction time of 5 - 15 minutes may be used depending on the nature of the raw materials.
  • During the microwave - assisted extraction, the microwaves heat the sample - solvent mixture, causing the active substances to be extracted into the solvent through a combination of physical and chemical processes. The rapid heating may also cause some chemical changes in the active substances, but these changes are usually within an acceptable range.

5. Filtration

5.1. Purpose

• After the extraction process, filtration is necessary to separate the extract from the solid residues. This helps to obtain a clear extract and remove impurities such as undissolved marigold powder particles.

• Simple filtration using filter paper in a funnel can be used for small - scale laboratory extractions. This method is simple and cost - effective but may be time - consuming for large - volume extractions.
• For larger - scale production, vacuum filtration or membrane filtration may be employed. Vacuum filtration can speed up the filtration process by applying a vacuum, while membrane filtration can achieve a higher level of filtration precision, removing even smaller particles.

6. Drying

6.1. Purpose

• The purpose of drying the filtered extract is to remove the solvent and obtain a dry marigold extract product. This not only reduces the volume of the product for easier storage and transportation but also stabilizes the quality of the extract.

• Similar to the drying of raw materials, drying of the extract can be carried out using natural drying or artificial drying methods. However, due to the relatively small volume and different composition of the extract compared to the raw materials, different drying parameters may be used.
• For example, in the case of artificial drying using a drying oven, a lower temperature may be used to avoid over - drying or the destruction of active substances. A drying temperature of 30 - 40°C may be suitable for some marigold extracts.

7. Packaging

7.1. Packaging Materials

• The choice of packaging materials is important for maintaining the quality of the marigold extract. Commonly used packaging materials include amber - colored glass bottles, aluminum - foil bags, and plastic containers.
• Amber - colored glass bottles are often preferred as they can protect the extract from light, which may cause the degradation of some active substances. Aluminum - foil bags also provide good protection against light and moisture, and are suitable for small - quantity packaging.

• The dried marigold extract is carefully weighed and placed into the selected packaging materials. The packaging should be carried out in a clean and dry environment to avoid contamination.
• Proper labeling should be attached to the packaging, indicating information such as the product name, extraction method, batch number, and expiration date.

8. Conclusion

The preparation process of marigold extract involves multiple steps, from the collection and pretreatment of raw materials to extraction, filtration, drying, and packaging. Each step is crucial for ensuring the quality of the final marigold extract product. Different extraction methods have their own advantages and disadvantages, and the choice of method depends on various factors such as the target compounds, production scale, and cost. With the increasing demand for marigold extract in various fields, continuous research and improvement in the preparation process are expected to further enhance the quality and application potential of marigold extract.

FAQ:

What are the main raw materials for preparing Tagetes erecta L. extract?

The main raw material for preparing Tagetes erecta L. extract is, of course, the marigold (Tagetes erecta L.) itself. Marigolds are carefully selected for their quality and freshness. The flowers are the most commonly used part as they contain a high concentration of the desired compounds for the extract.

What are the advantages of enzymatic extraction in the preparation of Tagetes erecta L. extract?

Enzymatic extraction in the preparation of Tagetes erecta L. extract has several advantages. Firstly, it can be more specific in breaking down cell walls, which helps to release the target compounds more efficiently compared to some traditional extraction methods. It often operates under milder conditions such as lower temperature and pH, which can prevent the degradation of heat - or pH - sensitive compounds present in the marigold. This results in a higher quality extract with a more complete profile of the desired bioactive substances.

How does microwave - assisted extraction work in the preparation of Tagetes erecta L. extract?

Microwave - assisted extraction works by using microwaves to heat the marigold sample and the extraction solvent rapidly and uniformly. The microwaves cause the molecules in the sample to vibrate, which generates heat internally. This internal heating leads to an increase in the solubility of the target compounds in the solvent and also accelerates the mass transfer process. As a result, the extraction time can be significantly reduced while still achieving a relatively high extraction yield of the Tagetes erecta L. extract.

Why is filtration an important step in the preparation of Tagetes erecta L. extract?

Filtration is a crucial step in the preparation of Tagetes erecta L. extract. After the extraction process, there are often solid particles such as plant debris, enzymes (if enzymatic extraction was used), or other insoluble substances in the extract. Filtration helps to remove these impurities, ensuring a clear and pure extract. A pure extract is not only more aesthetically pleasing but also more stable and suitable for further processing or application, as the presence of impurities can interfere with the effectiveness or shelf - life of the final product.

How can the quality of Tagetes erecta L. extract be ensured during the drying step?

During the drying step to ensure the quality of Tagetes erecta L. extract, several factors need to be considered. Firstly, the drying temperature should be carefully controlled. If the temperature is too high, it may cause the degradation of some heat - sensitive compounds in the extract. Secondly, the drying method should be appropriate. For example, freeze - drying can be a good option as it can preserve the structure and activity of the compounds better compared to some other drying methods. Adequate ventilation during drying is also important to ensure the removal of moisture without causing any contamination or spoilage of the extract.

Related literature

• Optimization of Marigold (Tagetes erecta L.) Extract Preparation for Enhanced Bioactivity"
• "A Comprehensive Study on the Extraction of Bioactive Compounds from Tagetes erecta L."
• "Advanced Techniques in Tagetes erecta L. Extract Production: A Review"