The Science of Good Food by Andrew Schloss and David Joachim explains the mysteries of food and cooking. Check out topics like Caviar; Extracts; and Sweet Potatoes; plus recipes, including Acorn Squash Filled with Pumpkin Seed Risotto and Roasted Root Vegetables.
Since cooking began, cooks have been grinding, grating, and pureeing ingredients, sweating them in oil, steeping them in syrup, distilling them into vapors, or drying them to concentrate every drop of flavor they have to offer. However it is done, the goal is always the same: to extract the chemicals that give food flavor and deliver them to receptors on the tongue and in the nose before they dissipate. The process is tricky, for flavors are volatile, easy to release but difficult to capture and preserve.
Natural flavors are extracted from aromatic plant parts—seeds (mostly nuts and spices), bark (like cinnamon), flowers (like rose, violet, or chamomile), fruit (citrus, peppers, and berries are most common), and roots or rhizomes (like ginger or turmeric).
Herbs (aromatic leaves) are some of the most common flavorings in recipes, but they are not typically turned into extracts, except for industrial purposes. This is partly because herb flavors are readily available fresh and dried, but it is also because aromatic oils are far less concentrated in leaves than in other parts of plants, except for mint leaves. For example, dried cinnamon bark or pepper berries might be 15% aromatic oil, while dried basil or oregano leaves would have less than 1%.
Artificial flavor extracts are made by combining chemical compounds that make up the flavors of natural ingredients. Natural flavor extracts can be drawn only from highly aromatic ingredients, but imitation flavors can be created to resemble any food, from root beer to roast beef. The ability of flavor scientists to imitate practically any flavor drives much of the product innovation in processed food, inspiring the creation of orange-flavored prunes, maple-scented oatmeal, or sour cream-and-chive potato chips.
Aromatic chemicals tend to be concentrated in specialized cells near the surface of plant tissue or in channels between cells. As soon as the plant tissue is bruised, the aromatics are released. Mixing the tissue immediately with oil or another compatible medium draws the aromatic compounds from the plant into the extracting medium.
Several extraction techniques are used for making natural flavors.
|Natural Source||Flavor||Characterizing Chemical Species|
|Anise||Aniseed||Anethole, methyl chavicol|
|Cinnamon||Cinnamon bark||Cinnamaldehyde, eugenol|
|Ginger||Ginger||Gingerol, shogaol, geranial|
|Lemon||Lemon peel||Limonene, terpinene, pinene|
|Lime||Lime peel||Limonene, terpinene, pinene|
|Orange||Orange peel||Limonene, linalool, decanal, pinene|
|Peppermint||Macerated peppermint leaves||Menthol, menthone|
|Rose||Macerated rose petals||Geraniol, citronellol, nerol|
|Spearmint||Macerated spearmint leaves||L-carvone|
|Vanilla||Macerated vanilla bean||Vanillin|
|Wintergreen||Macerated wintergreen leaves||Methyl salicylate|
Essential oils are defined as aromatic, volatile flavors isolated from plant materials by steam distillation. The same basic production technique has been used since the 9th century. Plant material is loaded onto a grid and steam percolates up through the material, carrying the flavor compounds with it. The steam, along with the flavor compounds, is collected and condensed back into a liquid and recovered. Steam distillation is used to recover flavors for many herbs and spices. One disadvantage of essential oils is that they contain only the volatile flavor components of a herb or spice. Advantages are that they contain no colors or tannins. Citrus essential oils are held in sacs or glands just below the pigmented layer of the peel and are recovered by cold pressing of the peels. Lime oil can also be obtained by distillation. Undiluted, essential oils are hazardous.
Fruit flavors are obtained by concentration, using either vacuum or freeze concentration to remove water. Care must be taken to retain as many volatile compounds as possible and not damage the flavor with heat.
Enfleurage flavors are extracted by mixing macerated material with cold or warm fat. Flavors transfer to the fat and are then extracted from the fat with alcohol.
An extract is a solution obtained by passing alcohol or an alcohol-water mixture through a food material.
Oleoresins are concentrated extracts produced by removing the solvent from an extract using heat and vacuum. Oleoresins are dark and viscous and contain many of the notes that characterize a flavor.
Compound flavors used in food products are combinations of essential oils, oleoresins, and carriers produced by flavorists drawing on their experience and creativity.
See also (in the book): Flavor, Flowers, Food Additives, Herbs, Spices
This page created January 2009
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