In this article we want to know in depth what is considered the sweet taste, bitter taste, salty, spicy flavor, one that perhaps desconozcas, umami taste. To get into the topic begin defining the taste and flavor, two words that mean the same thing. Taste, quality of a substance that is perceived by the sense of taste. Flavor is defined as the sensation produced by the chemical compounds present in a food when simultaneously impress the senses of taste, smell and touch during chewing. Once we made this remark we can continue with the division of the different flavors:
The sour taste of foods is mainly due to the presence of organic acids, especially being rich vegetables these components. They are as acids or as salts, potassium and calcium, and contribute not only the flavor but also the nutritional value, as they have caloric value: about three kilocalories per gram. Acids in many cases also contribute to microbiological stability of foods and, as a rule, stability increases with increasing acidity. The most important are the malic acid (not citrus), tartaric acid (grapes), citrus (orange, lemon) and oxalic acid (spinach, chocolate). In rarer proportions polyphenolic acids also are kind, such as benzoic, caffeic, chlorogenic and gallic. Addition of natural acids in the food can also be other acids formed by fermentation. Thus, lactic acid is a product of lactic fermentation and can be found, for example, fermented milk, sour cabbage, olives, green onions and sausage; acetic acid is formed by acetic fermentation from the alcohol and is therefore the most characteristic component of vinegar. Among the inorganic acids, the most abundant food is phosphoric, usually in the form of phosphates, except tail soft drinks, which is as such an acid.
The sweet taste is associated primarily with the sucrose molecule, but so have hexoses (fructose and glucose), sugar alcohols (sorbitol, mannitol, xylitol) and some amino acids of the D series The various sugars and derivatives, in addition to their nutritional function, determine the sweet taste of many foods (honey, syrups, pastry and confectionery, etc.). Similarly, the sweet taste of fruit that increases with advancing the degree of maturation, is also due to the presence of free sugars. In addition to the sugars contained naturally in plant foods, they are more nutritionally significance of almost pure sugar, used to sweeten foods and beverages: sucrose, especially, but also fructose, glucose syrup, etcetera. There is a molecular basis for the sweet taste, so that it knows it must have an electronegative group and hydrogen bonds separated by a given distance. These requirements are necessary even though they do not appear, however, sufficient to explain, since slight variations in a molecule, which does not affect these requirements may determine that the sweet taste of a bitter change. Furthermore, the discovery that proteins may exist sweet taste such as thaumatin , has meant an extension in the type of chemical structures that can provide fresh flavor.
The salty taste is due to inorganic salts of low molecular weight. Sodium chloride or common salt is the genuine representative of the salty taste. Would be followed by lithium chloride, which is not used in feeding. Current recommendations to control or reduce sodium intake, have determined the search for other salts (potassium, ammonium) as a substitute for salt. Cations appear to be the cause of the saltiness, but only produce a pure salty taste of sodium and lithium. The potassium and other cations also produce bitter and metallic occasions. The chloride anion does not inhibit salty taste and does not have any taste itself, which themselves become more complex anions. The sodium chloride is the salt that has the purest salty taste. Chlorides of magnesium, potassium and calcium salts, also provide saltiness, but in this case together with a residual bitter taste.
The bitter taste has common features with the sweet with respect to the chemical structure of molecules that produce them. But, unlike what happens with other flavors, no single chemical structure responsible. They can provide bitter taste: alkaloids, glycosides, flavonoids, terpenoids, xanthine bases (caffeine), most of the L-amino acids, many peptides, some products of the Maillard reaction, oxidized fatty acids and so on. The bitter character is associated in many cases spoiled food, which have been initiated putrefaction reactions releasing peptides and other bittering substances. However, the hydrolysis of proteins can also lead to bitter compounds in certain proportions, contribute to the characteristic flavor of fermented or cured products. The tannins also influence the bitterness, astringency confer as to foods that contain them. But not just tannins, but also other polyphenols. Thus, naringin (one anthoxanthin) is a bitter principle of grapefruit and bitter oranges. In these citrus fruits, however, primarily responsible for the bitterness it is limonene , which is structurally a terpenoid. The bitter taste is an important feature of the flavor of stimulating beverages like coffee and tea, which is due, at least in part, some alkaloids, the xanthine bases, caffeine and theobromine. It is another drink beer with a characteristic bitter taste due to the hops components of isoprenoid nature and lupulona humulone . The quinine alkaloid is a cinchona bark which is considered as the most representative of bitter substance. His main interest stems from its incorporation to the type soft drinks tonic water, which gives it its distinctive flavor. Caffeine is also part of the soft drink cola and therefore contributes to its flavor.
The pungency certain compounds found in various vegetables and, especially, spices, consisting of a stinging and burning sensation, which easily passes should irritating. Highlights in this respect the principles of certain varieties spicy paprika (páprica or chili) and pepper. The capsaicin is the most typical representative of the capsaicinoids, which are crucial to the compounds of spicy paprika (Capsicum) which are structurally vainililamidas of unsaturated carboxylic acids. The black and white peppers, both obtained from the seeds of Piper nigrum, whose main hot start to the piperine , which is chemically an amide. In addition to the spicy substances other spices contain volatile aromatic principles s that bring flavor to foods that season.
The four classic flavors (sweet, salty, bitter and sour), it should add a fifth, umami taste , typical of protein products such as meat products (soups, broths and sauces) and fish, dairy products, vegetable proteins like soy and even vegetables. This flavor indicates the presence of amino acids and proteins and is especially due to monosodium glutamate and certain nucleotides (sodium inosinate and guanylate). These compounds are found naturally in foods, but can also be added as flavor enhancers and aroma (flavor). Maltol and ethyl maltol roasted malt and other baked products also have the ability to enhance the flavor.
There are interactions between flavors and factors influencing the perception of them. For example, sucrose reduces the salty taste and the salt (sodium) lowering the sweetening power of sugar. Moreover, both, salt and sugar, reduce bitterness. Factors that can influence the perception of flavors include temperature and feed consistency. Sweet flavors and acids seem more pronounced hot-cold, while less salty and bitter intense heat. Overall, extreme temperatures reduce sensitivity of taste, albeit temporarily. All the flavors are perceived more easily in liquid on solid foods because sapid, water soluble substances are solubilized in the saliva, through it, interact with the taste receptor.