Essential oil recovery from bergamot juice by supercritical and liquid carbon dioxide

This study makes important observations about the alteration of fruit juice aroma compounds during extraction by CO2-SC. Supercritical carbon dioxide extraction is a promising technique for gentle stripping of fruit juice aroma compounds and deserves further consideration as alternative technique for gentle aroma stripping in industrial fruit juice processing. We have investigated the recovery of a useful fraction from bergamot juice. Usually this juice is a by-product of the citrus industry. The chemical composition of the fraction obtained by SC-CO2 is very different compared to the hydrodistillate. In the hydrodistillate by Clevenger apparatus, the main compound was limonene (higher than 40% of the total peak areas) and other hydrocarbons, such as γ-terpinen (6%) were present. In the alcoholic fraction α-terpineol (about 25%) and linalool (10%) were well represented, linalyl acetate (1-2%) and neryl acetate (0,5%) appeared in low quantity. The chemical composition of the volatile fraction extracted by SC-CO2 at 80 bar and 50°C, showed a large amount of linalyl acetate (about 40% of the total peak areas). In this extract the limonene made up only 20% of the total volatile compounds and also other terpene hydrocarbons decreased. This process produces an extract which is rich in the desirable lower molecular weight flavor and aroma compounds and low i the undesirable higher molecular weight flavor and aroma compounds which could impart off-flavors.