1. steam distillation
The production of natural flavors by steam distillation mainly includes three forms: water distillation, water distillation and steam distillation. Although various vegetable oils such as essential oils, rapeseed oil and olive oil are different, they all have the properties of easy volatilization, so they are also called volatile oils. In addition, most of the essential oils are insoluble or less soluble in water, so natural fragrance workers use steam distillation to extract them from various tissue cells and secretions of plant raw materials according to the characteristics of essential oils. This method is the easiest to use for some aromatic components that are less variable in contact with water vapor. Therefore, steam distillation is the most commonly used technology, which is characterized by simple equipment, easy operation, low cost and large output; however, steam distillation is not suitable for plants whose main aroma components are easily dissolved, hydrolyzed or decomposed in boiling water. raw material.
2. solvent extraction
The solvent extraction method is to extract the aromatic components from the plant raw materials with volatile organic solvents, dissolve them in the organic solvent, and then evaporate the solvent. Its characteristic is that it can be carried out at low temperature without heating. In addition to volatile components, important components and non-volatile components can also be extracted. However, when removing the solvent, the organic solvent extraction method will cause product quality degradation or organic solvents. Residues therefore limit the application range of some natural flavors.
3. squeezing
The pressing method is also one of the methods for extracting essential oils from plant aromatic raw materials, but there are not many varieties of this method, and its application range is not as extensive as that of steam distillation. This method is mainly used in the manufacture of citrus essential oils, such as the peel of lemon, sweet orange, bergamot and white lemon. The pressing method is not subject to heat during the processing, so it is also called the cold pressing method. The cold pressing method used in foreign countries is actually the cold grinding method of whole fruit. Domestic food factories mainly use fruit grinders for cold grinding to extract citrus oil, or screw pressing method for loose skins.
