Citrus peel contains essential oils. These oils are formed in the cells of the so-called oil glands, and they are some of the most important by-products obtained from the processing of citrus fruit.

Essential oils are also much in demand as taste and aroma agents for the food industry and also for the production of odorous substances. Several methods are available for recovering essential oil.

Juice and oil are extracted in one process step where FMC extractors are used for processing citrus fruit.

In other methods of recovering juice, either the peel of the citrus fruit is pricked before the extracting process and the oil which appears is washed away with water (BROWN), or the outer section of peel (flavedo) is rasped before being mixed with water and then further processed (INDELICATO).

The oil-water emulsion obtained in modern fruit processing lines contains approximately 70 to 90 % of the essential oil naturally present in the peel. The so-called peel wash water contains between 2 and 5 kg essential oil as emulsion per 100 kg of raw material processed depending on the type of fruit and the processing technology used.

One of the most important criteria in oil recovery from peel wash water is the efficiency of the downstream phase separation system.

Depending on the type of fruit, the proportion of oil in the wash water is between 0.5 and 2.0% (vol.). In the concentration stage (first stage) this oil is generally concentrated up to 70 to 85% (vol.). At the same time, relatively coarse solids fractions are separated off.

The total volume of oil contained in the peel wash water can be efficiently recovered as clear essential oil with a suitably rated two-stage centrifuge system.