Oleoresins are semi-solid extracts composed of a resin in solution in an essential and/or fatty oil, obtained by evaporation of the solvent(s) used for their production. Naturally occurring oleoresins are also known as balsams.
In contrast to essential oils obtained by steam distillation, oleoresins abound in heavier, less volatile and lipophilic compounds, such as resins, waxes, fats and fatty oils. Gummo-oleoresins (oleo-gum resins, gum resins) occur mostly as crude balsams and contain also water-soluble gums.
Oleoresins are prepared from spices, such as basil, capsicum (paprika), cardamom, celery seed, cinnamon bark, clove bud, fenugreek, fir balsam, ginger, jambu, labdanum, mace, marjoram, nutmeg, parsley, pepper (black/white), pimenta (allspice), rosemary, sage, savory (summer/winter), thyme, turmeric, vanilla, West Indian bay leaves. The solvents used are nonaqueous and may be polar (alcohols) or nonpolar (hydrocarbons, carbon dioxide).