What are the different types of flavours and fragrances and why is the SCFE process preferred for their extraction?

ByLily A Singh

Extraction of flavours and fragrances is a delicate operation because flavours and fragrances are fragile and easily distorted by heat and chemical action, both of which are often utilized in their extraction.

Applications of:

  • Flavours include industries such as beverages, bakery, confectionary, dairy, and convenience foods.
  • Fragrances consist of the cosmetics, toiletries, soaps, detergents, and fine fragrances. 

As many as 250 species of plants serve as the source for the 500 odd raw materials that go into making flavours and fragrances. Rose oil, tuberose absolute, angelica root oil, jasmine absolute, ambrette seed oil, and orange flavour oil are some of the most valued flavours and fragrances. 

Flavours and fragrances can also be natural or aroma chemicals.

  • Natural:
    • Oleoresins such as paprika (piperine), turmeric (curcumin), black pepper (piperine), gingerol, and ginger.
    • Essential Oils viz. orange (myrcene, limonene), eucalyptus (limonene, eucalyptol), lemon (limonene, pinene, camphene), corn mint (menthone, menthol), and peppermint (menthone, menthol).
  • Aroma Chemicals:
    • Esters include benzyl acetate, methyl decanoate, ethyl acetate, and ethyl benzoate.
    • Aldehydes such as vanillin and benzaldehyde.
    • Alcohol viz. Menthol and lauryl alcohol.
    • Phenol includes ethylvanillin. 

Extraction of flavours and fragrances employs processes such as:

SCFE is by far the best method for the extraction of flavours and fragrances because it does not employ heat or solvents, both of which can damage the fragile flavours and fragrances. And when the procedure uses carbon dioxide as the supercritical fluid (SCF), the process temperature is just around the room temperature – something that avoids thermal distortion or the change in molecular structure under the action of heat. 

Steam distillation and hydrodistillation both use heat. The former has a harsher action on raw materials while the latter can thermally distort them. As compared to steam distillation, extracts obtained via SCFE are cleaner, fresher, and crispier. 

Solvent extraction dissolves the flavours-fragrances in the solvent and then separates them. The separation is not complete and solvent residues linger with the flavour-fragrance. Such contamination negatively affects their end function. 

The reason SCFE is so effective is because it uses a supercritical fluid (SCF) – one whole solvent power can be adjusted to isolate only the required flavour or fragrance compound. Little or no amounts of other compounds get associated with the required compound. Solvent power is the capacity of the SCF to dissolve the required compounds. 

At high pressure, the SCF has high solvent power and it dissolves the required compound. When pressure is lowered, its solvent power falls and the required compound separates out.