Capsaicin

Most of the hot in hot peppers comes from capsaicin and a closely related compound, dihydrocapsaicin. It occurs in much lower quantities in oregano, cinnamon, and cilantro.

The compound's molecular weight is the highest of any of the vanilloids we've looked at so far, and the side chain contains a polar amide (-NHCO-) group. That makes capsaicin's volatility very low, and it is completely odorless. (A very good thing!)

Even without a telltale fragrance, capsaicin's presence in foods is hard to miss. A solution that contains only 10 parts per million produces a persistent burning sensation when placed on the tongue. It is tasteable at much lower concentrations. The intense flavor results from the molecule's long hydrocarbon tail. The chain allows it to bind very strongly with its lipoprotein receptor, which has some hydrocarbon side chains of its own (like dissolves like!) The fatty tail also allows the molecule to slip through lipid-rich cell membranes, making the burn more pervasive and persistent.

Several capsaicin-like compounds found in chiles have slight structural variations in the hydrocarbon tail, which changes their ability to bind to the receptors and their ability to penetrate layers of receptors on the tongue, mouth, and throat. That may explain why some chiles burn in the mouth, while others burn deep in the throat.

The perception that peppers are "hot" is not an accident. The capsaicin key opens a door in the cell membrane that allows calcium ions to flood into the cell. That ultimately triggers a pain signal that is transmitted to the next cell. When the cells are exposed to heat, the same events occur. Chile burns and heat burns are similar at the molecular, cellular, and sensory levels.

One expects that the long hydrocarbon tail will make capsaicin less water soluble than vanillin. This is indeed the case. Capsaicin is insoluble in cold water, but freely soluble in alcohol and vegetable oils. This is why drinking water after munching an habanero pepper won't stop the burning. A cold beer is the traditional remedy, but the small percentage of alcohol will not wash away much capsaicin. For relief from a chile burn, drink milk. Milk contains casein, a lipophilic (fat-loving) substance that surrounds and washes away the fatty capsaicin molecules in much the same way that soap washes away grease.

High concentrations are toxic. Exposure is painful and even incapacitating. Capsaicin prevents nerve cells from communicating with each other by blocking the production of certain neurotransmitters; at high concentrations it destroys the cells! Capsaicin's toxicity makes chiles more than just a food- they're also a weapon. The Mayans burned chiles to create a stinging smoke screen, and threw gourds filled with pepper extract in battle. Nowadays, capsaicin is the active ingredient in pepper sprays, used to ward off attacking muggers, dogs, and bears.

Paradoxically, capsaicin's ability to cause pain makes it useful in alleviating pain. Exposure to capsaicin lowers sensitivity to pain, and it is applied as a counter irritant in the treatment of arthritis and other chronically painful conditions.

People that eat lots of spicy capsaicin-rich foods build up a tolerance to it. The incentive: a small jolt of capsaicin excites the nervous system into producing endorphins, which promote a pleasant sense of well-being. The endorphin lift makes spicy foods mildly addictive (and for some, an obsession).

Food Flavor

Zingerone

Zingerone is principal organic compound responsible for giving ginger its pungent taste. It is a crystalline solid that is sparingly soluble in water, but soluble in ether. Scientific name for zingerone is 4-(4-hydroxy-3-methoxyphenyl)-2-butanone.

It puts the zing in ginger and is also a flavor ingredient in mustard oil. The hydrocarbon tail attached to its vanillin foundation ring doesn't lower the solubility of zingerone much because it contains a carbonyl group (C=O) that can form strong hydrogen bonds with water molecules. Zingerone is sparingly soluble in water, but also freely soluble in fats and oils.

The higher molecular weight of zingerone in combination with the polar side-chain carbonyl group makes zingerone molecules attract each other more strongly than eugenol and vanillin molecules do. As a result, zingerone is less volatile than either eugenol or vanillin. The odor of ginger isn't strong, but the hydrocarbon tail gives it a more intense flavor when it does come into contact with its receptor. Fresh ginger does not contain zingerone; cooking the ginger transforms gingerol, which is present, into zingerone.

Ginger root is a popular folk medicine. Some of the beneficial medicinal qualities claimed for ginger may stem from zingerone's effectiveness as an antioxidant. Zingerone reacts with free radicals that can cause tissue damage and inflammation. Studies by research scientists shows how that a topically applied extract containing zingerone may help prevent some skin cancers.
Zingerone

Eugenol

Eugenol (C10H12O2), is an allyl chain-substituted guaiacol, i.e. 2-methoxy-4-(2-propenyl)phenol. Eugenol is a member of the allylbenzene class of chemical compounds. It is a clear to pale yellow oily liquid extracted from certain essential oils especially from clove oil and cinnamon.

It's slightly soluble in water and soluble in organic solvents. It has a pleasant, spicy, clove-like odor. Eugenol is found in bay leaves, allspice, and oil of cloves.

Eugenol has a short hydrocarbon chain attached to the ring, which makes it much less water-soluble than vanillin. Although it is practically insoluble in water, it freely mixes with fats and oils.

Its fat solubility allows it to penetrate tissues and bind more tightly to the vanilloid receptor, which is believed to have a fatty side chain. The tail gives eugenol a stronger odor than vanillin has. One bay leaf is enough to season a pot of soup; more than one or two ground cloves overpower a pumpkin pie.

 Eugenol has a numbing, analgesic effect. It is used as a dental antiseptic (it's one component of that strange smell some dentist's offices have). Why is the molecule an antiseptic? Apparently the hydrocarbon tail in combination with the polar OH group on the ring make eugenol rather soap-like, and it can disrupt the cell membranes of bacteria the way soap disrupts a spot of grease.

Overdose is possible, causing a wide range of symptoms from blood in the patient's urine, to convulsions, diarrhea, nausea, unconsciousness, dizziness, or rapid heartbeat.
Eugenol

Vanillin

One example of food flavor is Vanillin which has a soothing, pleasant aroma. Its molecular weight is relatively low, and it is fairly volatile. Cooking with vanilla vaporizes some of the vanillin molecules and fills the room with its aroma.

Molecules containing only carbon and hydrogen are mostly insoluble in water. The oxygen-containing groups attached to the ring in vanillin can form strong hydrogen bonds with water, making it water soluble (about a gram of vanillin can be dissolved in 100 mL of cold water).

Vanillin's solubility in water is responsible for the "finish" acquired by wines aged in oak casks. Vanilla present in the wood lignin of the wine barrels slowly leaches into the wine over time.
Vanillin

Molecular fundamental of food flavor

A similar lock-and-key type of model has been used to explain why different substances have different flavors. The stereochemical theory of odor suggests that a molecule that fits into an olfactory receptor can fire nerve cells, ultimately producing a particular odor perception.

Five basic odors were associated with different molecular shapes. Football shaped molecules fit in to a "camphoraceous" receptor, and smell like mothballs. Necklace-shaped molecules have a musky odor because they fit into a "musky" receptor. Wedged-shaped molecules have a pepperminty odor, tadpole-shaped molecules smell like flowers, and long thin ether molecules are, well, ethereal.

Putrid and pungent smells were explained on the basis of partial charges on atoms within the molecule, rather than by shape alone. Putrid molecules have a buildup of negative charge somewhere in the molecule that's strongly attracted to a partially positive site on the "putrid" receptor. Pungent molecules (like acetic acid, in vinegar) are just the opposite: they have an electron-deficient region that is strongly attracted to an electron-rich site on the "pungent" receptor.

These seven receptors were believed to be the only letters in the olfactory alphabet in Amoore's version of the theory, published in the early 1970's. Molecules that can lock into more than one receptor have more complex odors. For example, Amoore explained the almondy odor of benzaldehyde by showing that it could fit comfortably into the postulated shapes for the camphoraceous, floral, and pepperminty receptors.

Amoore's stereochemical theory is now known to be an oversimplification, but it's still useful in relating smells to molecular shapes. There are over a thousand olfactory receptors, not just seven. The molecule's ability to move through tissue containing layer after layer of receptors also determines how its odor is perceived.

For example, attaching a hydrocarbon tail to a molecule improves its solubility in fats and alters its behavior at cell membranes. Perfume chemists have long known that adding a hydrocarbon tail to some perfume molecules increases their potency. Next article we will look to some specific examples.
Molecular fundamental of food flavor

Food Flavor

Flavor is a biological perception, a sensation produced by a material taken in the Mouth. It is the aggregate of the characteristics of the material that produces the sensation of flavor.

Flavor is perceived principally by the aroma receptors in the nose and taste receptors in the mouth. It is said that there are basically five flavors namely sweet, sour, bitter, salt and savory. What we experience as flavors is a combination of these with the odors.

 A flavor can in other terms be called the essence of food. Earlier it was considered that there are just four flavors. It was just in the recent years the fifth flavor, that of natural amino acid glutamic acid and certain nucleotides was observed.

This flavor is best noticed in Monosodium Glutamate. The Japanese named this flavor umami and it was translated as savory in English. Natural products have aroma chemicals that together with the taste create the flavor.

Coffee for example contains over 800 aroma chemicals other s may have them in lesser number yet more in quantity as in vanilla where the major flavoring component is vanillin. Some of the synthetic flavorings are prepared using these major components and others are complex mixtures.

Some flavors are created due to certain chemical processes like fermentation, roasting, or frying etc. These processes initiate chemical reactions in the food leading to specific flavor generation.

For example the flavor of fried onions is due to a reaction that takes place between its proteins and carbohydrates. Almost all the flavors can be classified into following categories: Fruit, Vegetable, Spice, beverage, Meat, Fat, Cooked, Empyreumatic and Stench.
Food Flavor

Nature of flavor components

The range of natural and synthetic flavorings available to the modern food technologists is very large. Essential oils form a major source of flavorings.

Essential oils are odorous components of plants and plant materials that are characteristics odors of the materials form which they are extracted. Because of the large production of orange juice, quality of essential oil of orange are produced as by products.

For this reason, there is little need for the production of synthetic orange flavorings. Fruits extract has being used as flavorings, but these are relatively weak when compared to essential oils and oleoresins.

An oleoresin is a solvents extract of spices from which the solvent, usually a hydrocarbon, has been removed by distillation. Because of their weak effects, fruits extract may be intensified by combining them with other flavor.

Synthetic flavorings are usually less expensive and more plentiful than natural flavorings. On the other hand, natural flavorings are often more acceptable. However, they are quite complex and difficult to reproduce synthetically.

In fact, one of the problems with natural flavorings is that they may vary according to their season and their uncontrollable variance.

Synthetic flavorings, however, can be reproduced quite accurately, many artificial flavors, such as amyl acetate (artificial banana flavor), benzaldehyde(artificial cherry flavor), and ethyl caproate(artificial pineapple flavor), are added to confectioneries, baked products, soft drinks, and ice cream. These flavorings are added in concentrations of 0.03% or less.
Food Flavor

Nature of flavor components

Plant materials used in foods depend for their characteristics aroma and flavor on a complex blend of organic chemicals produced in the plant tissues during its normal growth.

Hundred of chemicals present in natural foods and flavorings have already positively identified but some still defy categorization.

Nature is complex and does not readily reveal many of her secrets. The techniques necessary to separate aromatics compounds from inert plant tissues are often involved and tedious

Many of the chemicals which have most significance on the odor and flavor profile are known to be present only in trace quantity and often demonstrate very limited stability when isolated purified.

All these factors make research into the chemistry of flavor components one of extreme complexity but, in spite difficulties, considerable progress has been made.
Food Flavor

Classification of natural food flavor

Food Flavor
Natural food flavor generally may classify into three distinct groups.
Low flavor impact
Medium flavor impact
High flavor impact

Those in the group in the first form the basis of a staple diet providing a full range of protein, fats, carbohydrate and vitamins necessary to maintain the body in good health.

Those in the second group occupy half way place in that they are usually eaten in the natural state either as part of a meal to produce entirely different flavor sensation the mouth, or at other times as a snack.
Food flavor

Classification of food flavor

Food Flavor
The flavor of food is all important. Much of our diet by itself is unattractive, unappetizing and often so lacking in intrinsic flavor.

If the aroma and flavor is enticing and satisfying to the eater then it is digested better and results in an overall feeling of satisfaction.

It does not matter how the is look and how balanced nutritionally it is, if its does not smell and taste goods then these essential reflexes are not activated and eating remains mere chore rather than the positive pleasure which it should be.

The flavor of any food product, confectionary or beverage will depend upon all ingredients used in its preparation and the nature of processing involved.

Therefore, the knowledge of component of any products is necessary important.
There are may classified as:
*Prime ingredients
*Flavorings
*Colorings
*Additives or stabilizer
Classification of food flavor

What is food flavor?

Flavor is one of the most important sensory qualities of a food. Flavor can refer to a biological perception, such that is the sensation produced by a material taken in the mouth or flavor can refer to an attribute of the material being perceived.

Food flavor normally are compounds, many of which are natural, although there are also many synthetic ones, which are added to foods to flavors or to modify existing flavors.

The flavor is determined by a complex mixed of taste, aroma, chemical response and texture.

Food flavor may be a single chemical entity of naturals or synthetic origin. In the early days of human existence, salt, sugar, vinegar, herbs, spices were added to foods to improve their taste or to produce special, desirable taste.

Spices have been used in food for a long time. They contain essential oils, which contribute toward the fine aroma.

The range of natural and synthetic flavorings available to the modern food technologists is very large.

Food flavor includes taste sensations perceived by the tongue- sweet, salty, sour, bitter and smell perceived by the nose.

Consumers consider flavor one of the three main sensory properties decisive in their selection, acceptance and ingestion of a particular food.

Often the term flavor and smell are used interchangeably. Food flavor and aroma are difficult to measure and difficult to get people to agree on.

Flavor is a broader concept that either taste or aroma; aroma provides about 75% of the impression of flavor.

The flavor of food is created by aromatic chemicals that are biosynthesized during normal metabolic processes in plants and animals and possible further modified by cooking or processed.

Flavor regardless of the medium ion which they are dissolved, do not stay at the same intensity day after day, but diminished over time.
What is food flavor?