Grapefruit limonene content

SUMMARY In essential oils, most constituents are terpenes and terpenoid molecules. The method of extraction can influence the terpene content. In citrus oils extracted by expression (squeezing or pressing the plant material), the terpenes present are similar to those found in the living plant tissue for example, orange, lemon, mandarin and grapefruit essential oils may be made up of up to 90% of the monoterpene limonene. When extraction is by steam distillation the action of the hot water and steam on thermolabile (heat-sensitive) molecules present in the plant is responsible for the formation of the bulk of the terpene content. Solvent extraction often produces absolutes that are very low in terpenes or do not contain them at all, when compared to a distillation of the same material, for example as found in lavender and rose products. 

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