There are some 500,000 species of higher plants around the world, of which around 70,000 serve as a basis for plant-based drugs. Much as applications for vegetable active ingredients vary, they all share one common feature: they are extremely sensitive substances which have to be treated correspondingly gently by the biotechnical process used to obtain them. Extraction decanters and polishing separators from GEA are perfectly designed for this purpose.
Precise Adaptation to Process Parameters
The structure and biological activity of the substances mean that very specific medium conditions have to be used. The extraction process is particularly suitable for this, but has to be precisely adapted to suit process parameters such as pH, temperature, concentration and the delicate structure of the valuable substances. The efficacy of a phytopharmaceutical product also depends on adequate and consistent dosage of the plant extract, so industrial standardization is of huge significance.
Maceration or Percolation?
Plant extracts are defined as concentrated preparations of liquid, solid or viscous consistency. As a rule they are obtained by maceration (extraction to equilibrium with water or alcohol) or percolation (extraction to exhaustion with water or alcohol). A key factor in production is selection of the extraction agent. Water-soluble (hydrophilic) constituents can be extracted with water, whilst fat-soluble (lipophilic) constituents are extracted from a particular part of the plant with alcohol or other solvents.
Extraction Compared to Conventional Processes
Compared to competing separation processes such as distillation, concentration and membrane technology, extraction has proved more efficient in terms of process technology, more selective and cheaper in numerous applications. It is not only extremely gentle, but is also characterized by a low energy requirement.
Typical Plant Extraction Process
The extraction decanter and polishing separators from GEA used in the nutraceutical and pharmaceutical industry cover all processes and modes of operation: liquid-liquid extraction can be realized, as can liquid-liquid-solid and liquid-solid extractions, whether in one or more stages on the concurrent, counter-current and cross-current principles. The flow chart shows a typical plant extraction process.