Flavor

This article is about flavor as a sensory impression. For the particle property, see Flavour (particle physics). For other uses, see Flavor (disambiguation).

Flavor (American English) or flavour (British English; see spelling differences) is the sensory impression of food or other substances, and is determined primarily by the chemical senses of taste and smell. The "trigeminal senses", which detect chemical irritants in the mouth and throat, as well as temperature and texture, are also important to the overall gestalt of flavor perception. The flavor of the food, as such, can be altered with natural or artificial flavorants which affect these senses.

A "flavorant" is defined as a substance that gives another substance flavor, altering the characteristics of the solute, causing it to become sweet, sour, tangy, etc. A flavor is a quality of something that affects the sense of taste.

Of the three chemical senses, smell is the main determinant of a food item's flavor. Five basic tastes – sweet, sour, bitter, salty and umami (savory) are universally recognized, although some cultures also include pungency and oleogustus ("fattiness"). The number of food smells is unbounded; a food's flavor, therefore, can be easily altered by changing its smell while keeping its taste similar. This is exemplified in artificially flavored jellies, soft drinks and candies, which, while made of bases with a similar taste, have dramatically different flavors due to the use of different scents or fragrances. The flavorings of commercially produced food products are typically created by flavorists.

Although the terms flavoring and flavorant in common language denote the combined chemical sensations of taste and smell, the same terms are used in the fragrance and flavors industry to refer to edible chemicals and extracts that alter the flavor of food and food products through the sense of smell. Due to the high cost or unavailability of natural flavor extracts, most commercial flavorants are "nature-identical", which means that they are the chemical equivalent of natural flavors, but chemically synthesized rather than being extracted from source materials. Identification of components of natural foods, for example a raspberry, may be done using technology such as headspace techniques, so the flavorist can imitate the flavor by using a few of the same chemicals present.

Flavorants or flavorings

Flavorings are focused on altering the flavors of natural food product such as meats and vegetables, or creating flavor for food products that do not have the desired flavors such as candies and other snacks. Most types of flavorings are focused on scent and taste. Few commercial products exist to stimulate the trigeminal senses, since these are sharp, astringent, and typically unpleasant flavors.

Three principal types of flavorings are used in foods, under definitions agreed in the EU and Australia:

Natural flavoring substances

These flavoring substances are obtained from plant or animal raw materials, by physical, microbiological, or enzymatic processes. They can be either used in their natural state or processed for human consumption, but cannot contain any nature-identical or artificial flavoring substances.

Nature-identical flavoring substances

These are obtained by synthesis or isolated through chemical processes, which are chemically and organoleptically identical to flavoring substances naturally present in products intended for human consumption. They cannot contain any artificial flavoring substances.

Artificial flavoring substances

These are not identified in a natural product intended for human consumption, whether or not the product is processed. These are typically produced by fractional distillation and additional chemical manipulation of naturally sourced chemicals, crude oil, or coal tar. Although they are chemically different, in sensory characteristics they are the same as natural ones.

Most artificial flavors are specific and often complex mixtures of singular naturally occurring flavor compounds combined together to either imitate or enhance a natural flavor. These mixtures are formulated by flavorists to give a food product a unique flavor and to maintain flavor consistency between different product batches or after recipe changes. The list of known flavoring agents includes thousands of molecular compounds, and the flavor chemist (flavorist) can often mix these together to produce many of the common flavors. Many flavorants consist of esters, which are often described as being "sweet" or "fruity".

Chemical	Odor
Manzanate	Apple
Diacetyl, acetylpropionyl, acetoin	Buttery
Isoamyl acetate	Banana
Benzaldehyde	Bitter almond, cherry
Cinnamaldehyde	Cinnamon
Ethyl propionate	Fruity
Methyl anthranilate	Grape
Limonene	Orange
Ethyl decadienoate	Pear
Allyl hexanoate	Pineapple
Ethyl maltol	Sugar, cotton candy
2,4-Dithiapentane	Truffle
Ethylvanillin	Vanilla
Methyl salicylate	Wintergreen

The compounds used to produce artificial flavors are almost identical to those that occur naturally. It has been suggested that artificial flavors may be safer to consume than natural flavors due to the standards of purity and mixture consistency that are enforced either by the company or by law. Natural flavors, in contrast, may contain impurities from their sources, while artificial flavors are typically more pure and are required to undergo more testing before being sold for consumption.

Flavors from food products are usually the result of a combination of natural flavors, which set up the basic smell profile of a food product, while artificial flavors modify the smell to accent it.

Unlike smelling, which occurs upon inhalation, the sensing of flavors in the mouth occurs in the exhalation phase of breathing and is perceived differently by an individual. In other words, the smell of food is different depending on whether one is smelling it before or after it has entered one's mouth.

Taste

While salt and sugar can technically be considered flavorants that enhance salty and sweet tastes, usually only compounds that enhance umami, as well as other secondary flavors, are considered and referred to as taste flavorants. Artificial sweeteners are also technically flavorants.

Umami or "savory" flavorants, more commonly called taste or flavor enhancers, are largely based on amino acids and nucleotides. These are typically used as sodium or calcium salts. Umami flavorants recognized and approved by the European Union include:

Acid salts	Description
Glutamic acid salts	This amino acid's sodium salt, monosodium glutamate (MSG), is one of the most commonly used flavor enhancers in food processing. Mono- and diglutamate salts are also commonly used.
Glycine salts	Simple amino acid salts typically combined with glutamic acid as flavor enhancers
Guanylic acid salts	Nucleotide salts typically combined with glutamic acid as flavor enhancers
Inosinic acid salts	Nucleotide salts created from the breakdown of AMP, due to high costs of production, typically combined with glutamic acid as flavor enhancers
5'-ribonucleotide salts	Nucleotide salts typically combined with other amino acids and nucleotide salts as flavor enhancers

Certain organic and inorganic acids can be used to enhance sour tastes, but like salt and sugar, these are usually not considered and regulated as flavorants under law. Each acid imparts a slightly different sour or tart taste that alters the flavor of a food.

Acid	Description	Formulation	pH
Acetic acid	Gives vinegar its sour taste and distinctive smell.	C 2H 4O 2	pH 3.91
Ascorbic acid	Found in oranges and green peppers and gives a crisp, slightly sour taste, better known as vitamin C.	C 6H 8O 6	pH 3.59
Citric acid	Found in citrus fruits and gives them their sour taste.	C 6H 8O 7	pH 3.24
Fumaric acid	Found in bolete mushrooms, Icelandic moss and lichen, Not found in fruits, used as a substitute for citric and tartaric acid. Enhances flavor and sourness.	C 4H 4O 4	pH 3.19
Lactic acid	Found in various milk or fermented products and give them a rich tartness.	C 3H 6O 3	pH 3.51
Malic acid	Found in apples and gives them their sour/tart taste.	C 4H 6O 5	pH 3.33
Phosphoric acid	Used in some cola drinks to give an acidic taste.	H 3PO 4	pH 3.06
Tartaric acid	Found in grapes and wines and gives them a tart taste. Also called racemic acid.	C 4H 6O 6	pH 3.18

Color

The color of food can affect one's expectations of the flavor significantly. In one study, adding more red color to a drink increased the perceived sweetness, with darker colored solutions being rated 2–10% better than lighter ones, though it had 1% less sucrose concentration. Food manufacturers exploit this phenomenon; different colors of Froot Loops cereal and most brands of gummy bears often use the same flavorings.

Restrictions and regulations

Regulations on natural flavoring

UK Food Law defines a natural flavor as:

A flavouring substance (or flavouring substances) which is (or are) obtained, by physical, enzymatic, or microbiological processes, from material of vegetable or animal origin which material is either raw or has been subjected to a process normally used in preparing food for human consumption and to no process other than one normally so used

The UK food industry also draws a distinction between a food being "X-flavoured", where it contains some amount of X as an ingredient, and "X-flavour", where it has the taste of X but does not contain it.

The U.S. Code of Federal Regulations describes a "natural flavorant" as:

The essential oil, oleoresin, essence, or extractive, protein hydrolysate, distillate, or any product of roasting, heating, or enzymolysis, which contains the flavoring constituents derived from a spice, fruit, or fruit juice, vegetable or vegetable juice, edible yeast, herb, bark, bud, root, leaf, or any other edible portions of a plant, meat, seafood, poultry, eggs, dairy products, or fermentation products thereof, whose primary function in food is flavoring rather than nutritional

The European Union's guidelines for natural flavorants are slightly different. Certain artificial flavorants are given an E number, which may be included on food labels.

Dietary restrictions

Food manufacturers are sometimes reluctant to inform consumers about the source and identity of flavor ingredients and whether they have been produced with the incorporation of substances such as animal byproducts. Some flavor ingredients, such as gelatin, are produced from animal products. Some, such as glycerin can be derived from either animal or vegetable sources. And some extracts, such as vanilla, may contain alcohol. Many Jews, Jains, Hindus, and Muslims adhere to religious dietary laws, and vegans to personal convictions, which restrict the use of animal byproducts and/or alcohol in foods unless subject to oversight and inspection by their respective religious authority or moral beliefs. In many Western countries, some consumers rely on a Jewish kosher pareve certification mark to indicate that natural flavorings used in a food product are free of meat and dairy (although they can still contain fish). The Vegan Society's Sunflower symbol (which is currently used by over 260 companies worldwide) can also be used to see which products do not use any animal ingredients (including flavorings and colorings).

Similarly, persons with known sensitivities or allergies to food products are advised to avoid foods that contain generic "natural flavors" or to first determine the source of the flavoring before consuming the food. Such flavors may be derived from a variety of source products that are themselves common allergens, such as dairy, soy, sesame, eggs, and nuts.

Flavor creation

Food and beverage companies may require flavors for new products, product line extensions (e.g., low fat versions of existing products), or changes in formula or processing for existing products. In 2011, about US$10.6 billion were generated with the sale of flavors; the majority of the flavors used are consumed in processed and packaged food.

Most flavors represent a mixture of aroma compounds, the raw material that is produced by flavor companies. In rare cases, a single synthetic compound is used in pure form. Artificial vanilla flavors vanillin and ethylvanillin are a notable exception, as well as the artificial strawberry flavor (ethyl methylphenylglycidate). The ubiquitous "green apple" aroma is based on hexyl acetate.

The flavor creation is done by a specially trained scientist called a "flavorist", whose job combines scientific knowledge of the chemical palette with creativity to develop new and distinctive flavors. The flavor creation begins when the flavorist receives a brief from the client. In the brief, the clients attempt to communicate exactly what type of flavor is sought, in what application it will be used, and any special requirements (e. g., it must be all natural). The communication barrier can be quite difficult to overcome since most people are not experienced at describing flavors. The flavorist uses his or her knowledge of the available chemical ingredients to create a formula and compound it on an electronic balance. The flavor is then submitted to the client for testing. Several iterations, with feedback from the client, may be needed before the right flavor is found.

Additional work may also be done by the flavor company. For example, the flavor company may conduct sensory taste tests to test consumer acceptance of a flavor before it is sent to the client or to further investigate the "sensory space". The flavor company may also employ application specialists who work to ensure the flavor will work in the application for which it is intended. This may require special flavor delivery technologies that are used to protect the flavor during processing or cooking so that the flavor is only released when eaten by the end consumer. The flavor obtained is determined not just by the simple presence of a flavorant or a mixture of flavorants, but also by their concentrations. Thus, even if a non-flavored ingredient is added/removed to/from a food or beverage, this can noticeably affect the final flavor if it dilutes or otherwise changes the concentrations of the remaining flavored ingredients.

Determination

Few standards are available or being prepared for sensory analysis of flavors. In chemical analysis of flavors, solid phase extraction, solid phase microextraction, and headspace gas chromatography are applied to extract and separate the flavor compounds in the sample. The determination is typically done by various mass spectrometric techniques. A flavor lexicon can aid the development of objective language for food.

Scientific resources

• Flavour and Fragrance Journal

See also

• Aroma compound
• Ester (for list of some artificial flavor chemical compounds)
• Food additive
• Fragrance oil
• Katsuobushi
• Off-flavour
• Palatability
• Seasoning
• Taste bud
• Artificial butter flavoring

External links

• How Stuff Works How do artificial flavors work?
• Monell Chemical Senses Center
• Flavornet