The orange peel contains the fragrance of the fruit, the “essential oil”. An essential oil is different that a “fixed oil” (nut or vegetable oil) which is not fragrant.
Flavor scientists value essential oils and they extract them so they can use them in flavors. These oils are excellent starting materials for flavoring beverages, but they need to be modified to be useful. They do not “go into” a beverage. We modify the oils to make them “go in” or make them “miscible”.
Chemists use miscible to explain the phenomenon of two liquids with similar polarities (intermolecular interactions) being combined uniformly.
In contract, chemists use soluble to explain the phenomenon of a solid (solute) dissolving in a liquid (solvent).
Some tricks of the trade flavorist use to make an essential oil miscible include:
1) Remove the immiscible constituents (terpenes) by steam or fractional distillation.
2) Extract the oil with a food grade solvent (such as alcohol) to obtain the water miscible parts of the essential oil.
3) Make an emulsion with the oil that can stay suspended in the beverage.
Knowledge of the desirable aromatic chemical components of essential oils as well as each component’s partition coefficient helps a flavor chemist decide what steps to take to develop a “miscible flavor”. It’s a puzzle I always enjoy solving. Tools that I find helpful in solving the puzzle include a list of chemical constituents and lists of partition coefficients.
An understanding of Stoke’s law and basic math is also needed to determine how to formulate a flavor for a particular beverage. Stoke’s law helps a flavor chemists formulate a flavor emulsion.
Flavor creation involves an understanding on how a flavor will perform in the desired food or beverage. A solid foundation of math and science is needed to formulate beverage flavors that will have the desired shelf life required by consumers ( six months to a year).
Interested in learning more about food science? Contact IFT (Institute of Food Technologists).