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In this installment of "Comparatively Speaking," industry expert Tony O'Lenick explains the difference between maceration and decoction.
An earlier column described extraction; this column continues with a related concept. Maceration is the extraction of a active in a solvent with shaking or stirring at room temperature. After a defined period, the spent, solid material is separated from the solution (macerate). On the other hand, decoction is a method of extraction that results from placing a matrix in a menstruum (solvent) that is then heated to boiling. The matrix may include leaves, stems, roots, bark and other plant materials.
Decoction involves mashing and then boiling in water to extract oils, volatile organic compounds and other chemical substances. The process has been used since antiquity for the preparation of traditional medicines. In traditional Chinese medicine, it is customary to place the quantity of herbs required for one day's treatment into a vessel, to which hot or boiling water is added. The vessel is then raised to boiling point and allowed to simmer. The decoction so produced is allowed to cool, separated from solid particles, and the decoction is used as the dosage form for oral administration.
Maceration is used in winemaking and is the process by which the red wine receives its red color. In the production of white wines, maceration is either actively avoided or allowed in a very limited manner in the form of a short amount of skin contact between the must prior to pressing. Maceration can also be used to make limoncello. Decoction is used in making tea. Maceration is generally less aggressive, extracting fewer actives.
A disadvantage of maceration and decoction with water or low concentrations of ethanol is that a large quantity of inert material (ballast) that has no therapeutic value is extracted. Ballast may consist of plant cell constituents including, but not limited to, fats, waxes, carbohydrates, proteins and sugars. This may contribute to microbiological spoilage if the product is not used promptly. If dried, the extracts so produced tend to be hygroscopic and difficult to formulate. The ballast may also affect the way in which the active constituents are absorbed from the finished dosage form.