Acids sour taste

A slightly different but equivalent definition of acids and bases is suggested by these equations. The first reaction results in an increase in hydronium ions (H O ). The second reaction results in an increase in hydroxide ions (OH ). Therefore, an acid can be defined as a chemical substance that, when added to water, results in an increase in the concentration of hydronium ions. A base is a chemical substance that, when added to water, results in an increase in the concentration of hydroxide ions. Hydronium ions give acid solutions the properties we associate with acids—sour taste, corrosiveness, and the ability to turn blue litmus paper red. Hydroxide ions give basic (or alkaline) solutions the properties of feeling soapy, causticity, and the ability to turn red litmus paper blue. 

Table 2 Hsts examples of compounds with taste and their associated sensory quaUties. Sour taste is primarily produced by the presence of hydrogen ion slightly modified by the types of anions present in the solution, eg, acetic acid is more sour than citric acid at the same pH or molar concentration (43). Saltiness is due to the salts of alkaU metals, the most common of which is sodium chloride. However, salts such as cesium chloride and potassium iodide are bitter potassium bromide has a mixed taste, ie, salty and bitter (44). Thus saltiness, like sourness, is modified by the presence of different anions but is a direct result of a small number of cations.

Only acids are sour. Sourness is not identical to chemical acidity or pH, which is a function of the hydrogen ion concentration, but also appears to be a function of the entire acid molecule. A combination of pH and acid concentration determines the actual degree of the sour taste. At the same pH, any organic acid, eg, citric acid, exhibits a far greater sourness than a mineral acid, eg, hydrochloric acid (27,28). 

Examples include hydrochloric acid, nitric acid, and sulphuric acid. These are strong acids which are almost completely dissociated in water. Weak acids, such as hydrogen sulphide, are poorly dissociated producing low concentrations of hydrogen ions. Acids tend to be coiTosive with a sharp, sour taste and turn litmus paper red they give distinctive colour changes with other indicators. Acids dissolve metals such as copper and liberate hydrogen gas. They also react with carbonates to liberate carbon dioxide ... 

The compound that gives vinegar its sour taste is acetic acid, which contains the elements carbon, hydrogen, and oxygen. When 5.00 g of acetic acid are burned in air, 7.33 g of C02 and 3.00 g of water are obtained. What is the simplest formula of acetic acid ... 

Vinegar. Vinegar gets its sour taste from acetic acid. 

You are probably familiar with a variety of aqueous solutions that are either acidic or basic (Figure 4.6). Acidic solutions have a sour taste and affect the color of certain organic dyes known as acid-base indicators. For example, litmus turns from blue to red in acidic solution. Basic solutions have a slippery feeling and change the colors of indicators (e.g., red to blue for litmus). 

Acetic acid, in the form of vinegar, is used to preserve foods such as pickles. It also provides the sour taste for salad dressings and mayonnaise. 

Lactic acid is what gives the sour taste to spoiled milk and to sauerkraut. It is used in foods to add tartness, and to preserve freshness in... 

Flavorings can be derived from simple acids that add a sour taste to foods, or they can comprise more complex molecules, such as dena-tonium benzoate, which is added to products to make them so bitter that no one will accidentally ingest harmful amounts. 

Carboxylic acids with one acid group are known as monobasic acids while those with two acid groups are dibasic acids. All acids with more than one acid group are in the class of polybasic acids. The simplest organic acid, formic acid, is responsible for the irritation of bee and ant stings. Vinegar is a 5% solution of acetic acid in water. The acetic acid is responsible for the characteristic sour taste. Citric acid, found in citrus fruits and used in soft drinks, is a tribasic acid with three carboxylic acid groups. The dibasic acid, adipic acid, is a major component of nylon. 

Boyle (1661) attempted to provide a more definite concept and attributed the sour taste of acids to sharp-edged acid particles. Lemery, another supporter of the corpuscular theory of chemistry, had similar views and considered that acid-base reactions were the result of the penetration of sharp acid particles into porous bases (Walden, 1929 Finston Rychtman, 1982). However, the first widely accepted theory was that of Lavoisier who in 1 111 pronounced that oxygen was the universal acidifying principle (Crosland, 1973 Walden, 1929 Day Selbin, 1969 Finston Rychtman, 1982). An acid was defined as a compound of oxygen with a non-metal. 

An acid is classically known as a substance whose aqueous solution (i) turns blue litmus red (ii) neutralizes bases (iii) reacts with active metals with the evolution of hydrogen and (iv) possesses a sour taste. A base is again classically known as a substance which in aqueous solution (i) turns red litmus blue (ii) neutralizes acids (iii) tastes offensive and (iv) gives a soapy feel. These given descriptions of acids and bases may also be regarded as being operational or or experimental definitions. 

Acids and bases are determined by their properties. The word acid comes from the Latin word acidus, which means sour. For example, lemon juice tastes sour because it contains citric acid. Sauerkraut, another sour-tasting food, is cabbage fermented in lactic acid. In fact, sauer (pronounced almost exactly like the English word sour) in German means acid. Sour cream also has lactic acid in it. 

Acid Substance which increases the acidity of a foodstuff and/or imparts a sour taste to it... 

The role of these tastes has been nicely summarized Taste is in charge of evaluating the nutritious content of food and preventing the ingestion of toxic substances. Sweet taste permits the identification of energy-rich nutrients, umami allows the recognition of amino acids, salt taste ensures the proper dietary electrolyte balance, and sour and bitter warn against the intake of potentially noxious and/or poisonous chemicals. ... 

Miraculin is a glycoprotein which not only shields a sour taste, it can also make you believe that what you are eating or drinking is actually sweet It is a 190 amino acid glycoprotein and its amino acid sequence was determined completely by Theerasilip and his Japanese colleagues.Miraculin... 

Perhaps no two classes of compounds are more important in chemistry than acids and bases. All acids have several properties in common They have a sour taste, and they all react with most metals to form hydrogen gas (Hj) and with baking soda to form carbon dioxide (CO2). All acids turn blue litmus paper red, and their solutions conduct electricity because acids form ions when dissolved in water. t 11 bases also share several common properties They have a bitter taste, their solutions feel slippery like soapy water, and they turn red litmus paper blue (the opposite of acids). Solutions of bases also conduct electricity because they too form ions in water. Acids are similar because they produce hydrogen ion, (aq), in water. Bases, on the other hand, all form hydroxide ion, 0 [ (aq), in water. These ions are responsible for the properties of acids and bases. 

Acidity and basicity are paired concepts that are very often invoked to explain the catalytic properties of divided metal oxides and zeolites. The concept of acids and bases has been important since ancient times. It has been used to correlate large amounts of data and to predict trends. During the early development of acid-base theory, experimental observations included the sour taste of acids and the bitter taste of bases, color changes in indicators caused by acids and bases, and the reaction of acids with bases to form salts. 

Aii acid solutions taste sour and are more or iess corrosive and chemicaiiy quite reactive they react with most metais, many of which are corroded and dissoived by acids. Alkaline solutions, aiso chemicaiiy reactive, are caustic (they burn or corrode organic tissues), taste bitter, and feei siippery to the touch. Both acids and bases change the coior of indicators (substances that change coior, hue, or shade depending on whether they are in an acid or basic environment). 

The sour taste of fruit is due to the fruit s own brand of acid. "Citrus fruits, for example, contain citric acid. In other fruits the sour taste is often disguised by the sweetness of fruit sugars. 

Sour and salty. Within the membrane of the taste cell are ion channels which control the movement of ions, such as sodium, potassium and calcium, into and out of the cell. Sour taste sensations are in part due to the effect of hydrogen ions however, some taste is also a function of the hydrophobicity of the organic acid, such as citric acid (18). Acids can produce a decrease in potassium ion conductance (depolarization) in the membrane. 

Sweetness Production by the Combination of Bitter and Sweet Tastes. Sensory tests using typically bitter compounds such as brucine, strychnine, phenylfiiiourea, caffeine and bitter peptides were performed. Sensory tests using typically bitter compounds such as brucine, strychnine, phenylthiourea, caffeine and bitter peptides were performed. Sensory taste impression were also measured for combinations of acetic acid (sour) and typical bitter compounds (5). The data from these studies indicated that the tastes of ese bitter/sour mixtures changed to a sweet taste regardless of their chemical structure of the bitter component (Table II). 

Other experiments were conducted to verify the conclusions drawn and described above. For example, benzoyl-e-aminoaproic acid (BACA), possesses a sour taste despite having a hydrophobic group in the molecule, i.e., it has an X-B component. If... 

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