There are five main commercial methods currently used for removing some or all of the water insoluble monoterpene hydrocarbons from orange oils to make flavors: Washing, folding and washing, folding, chromatographic and counter current.
The traditional method of incorporating expressed citrus oils into flavors is to dissolve the soluble portion into an alcohol-water mixture, then rejecting the insoluble portion (the washed oil).
This process is about 50% efficient and the remaining 50% of flavor stays unpartitioned in the washed oil.
A study of different concentrations of aqueous alcohol and cold pressed orange oil to solvent ratios, for deterpenation by washing techniques, has heen published. It was shown that by varying the proportions of alcohol and water solvent mix for extraction and the ratio of oil to solvent, a spectrum of monoterpene, sesquiterpene, aldehyde and alcohol contents from the orange oil could he derived.