Plant Concrete And Absolute Oil Extraction Processing

Plant concrete and absolute oils extraction are important processes for obtaining active ingredients from plants. The following introduces the common process points of the two:

Aromatic plant → extracted by hexane → hexane evaporation → concrete → extracted by ethanol (low temperature -15℃) → filtering solid impurities → ethanol evaporation → absolute oil

I. Process of plant concrete extract

1. Raw material pretreatment

Select dry, mildew-free plant raw materials (such as flowers, leaves, roots, etc.), crush them into appropriate particle sizes (such as coarse powder or granules) to increase the contact area with the solvent.

2. Extraction

Solvent extraction method: Solvents such as ethanol, water, and petroleum ether are commonly used for extraction by decoction, percolation, reflux or ultrasound assistance. For example, ethanol extraction is suitable for most natural ingredients, while water extraction is often used for water-soluble ingredients (such as polysaccharides and proteins).

Key: Select the solvent according to the solubility of the target ingredient, and control the extraction temperature, time and material-liquid ratio (such as material-liquid ratio 1:10-1:20).

3. Concentration

After filtering to remove the residue, the extract is concentrated by vacuum distillation (to reduce the boiling point and avoid the destruction of heat-sensitive components) or thin film evaporation until a thick paste is formed (relative density is usually 1.2-1.4, measured at 60°C).

4. Drying (optional)

If a solid extract is required, spray drying (suitable for heat-sensitive components), vacuum drying or freeze drying can be used to make powder or block.

II. Process of plant absolute oil

Absolute oil is mainly used for natural fragrance extraction, and the process focuses more on the purification of volatile components. The common methods are as follows:

1. Extract preparation (pretreatment)

First, the plant extract is obtained by solvent extraction (such as petroleum ether, ether). At this time, the extract may contain impurities such as wax and pigment.

2. Dewaxing treatment

Low-temperature freezing method: dissolve the extract in an organic solvent (such as ethanol), let it stand at low temperature (-10°C to -20°C) to precipitate the wax, and filter it out.

Recrystallization method: Utilize the difference in solubility between wax and target component in different solvents, and purify by multiple dissolution-crystallization.

3. Concentration and purification

The dewaxed solution is distilled under reduced pressure to remove the solvent, and a relatively pure oily substance is obtained, namely, the clean oil. Some processes will combine column chromatography (such as silica gel column) to further separate impurities and improve purity.

4. Quality control

Detect the aroma, color, relative density, refractive index and other indicators of the clean oil to ensure that it meets the standards of fragrance or medicinal use.

3. Comparison of process differences between the two

Concrete extract: Focus on the comprehensive extraction of components, the process is simple, and the product is a thick paste or solid, which is commonly used in traditional Chinese medicine preparations, food additives, etc.

Absolute oil: The goal is to purify volatile components (such as aromatic substances). The process has one more step of dewaxing and fine purification, and the product is liquid, which is mainly used in high-end fields such as flavors and cosmetics.

The specific process needs to be adjusted according to the plant species, target components and application scenarios. For example, rose absolute oil needs to avoid high temperature to destroy the aroma components, and low-temperature solvent treatment is often used.