What chemicals are considered responsible for bitter, sour, salty, and sweet tastes? When you eat candy or pickled cucumber, you notice the difference, because the tongue has special bumps or papillae on which taste buds are located to help you talk about the difference between different products. Each receptor has many receptor cells that can recognize different tastes. Chemical compounds that have an acidic taste, bitter or sweet, can bind to these receptors, and a person feels the taste without even looking at what he eats.
Acid Receptors
Taste is the ability of nerve cells in the mouth, throat and nose of a person and the body to sense certain chemical compounds and transmit a message to the brain that identifies them. The smell, texture and temperature of the substance contribute to the taste sensation, which is transferred to the taste buds by saliva. This not only stimulates appetite, but also helps to identify hazardous substances. Four classic taste sensations - bitter, sour, salty and sweet.
What are sour tastes? Sour taste, as it is logical to assume, have acidic foods. Acids in food emit hydrogen ions or protons. The concentration of hydrogen ions determines the degree of acidity. Decomposition of food by bacteria causes acidic or hydrogen ions, and while some fermented foods, such as yogurt, have a pleasant acid, but sometimes this taste can be a warning about bacterial contamination of food.
Hydrogen ions bind to acid-sensitive channels in the membranes of taste cells. When the channels are activated, they affect the nerves. Early research has linked acidic tastes primarily to production using hydrogen ions that block potassium channels, but a recent study identifies the oxygen-sensitive cationic channel as the primary transducer of acidic tastes.
Bitter taste receptors
Taste buds are responsible for distinguishing between bitter, sour, salty, or sugary foods. The bitter taste is caused by acids, chemical compounds such as sulfamides, alkaloids, glucose, fructose, ionized salts, glutamate. Many alkaloids, which are usually toxic, cause a bitter taste, as well as quinine, which binds receptors that bind to specific proteins. Their activation initiates a signal cascade, which causes a feeling of bitterness.
Humans have 40-80 types of bitter taste receptors that detect various substances, including sulfamides, such as saccharin, urea, and alkaloids, including quinine and caffeine. Children have more taste buds than adults, and the number of taste receptors decreases with age. In addition, children often do not like vegetables, which may be due to the production of bitter compounds by plants to protect them from animals that eat them. Sensitivity to bitter compounds also depends on genes encoding bitter taste receptors. Variations of these genes prevent some people from detecting bitterness in some compounds.
Bitterness is a taste associated with substances containing polyphenols, flavonoids, isoflavones, glucosinolates and terpenes. They are present in fruits and vegetables and many plant foods such as coffee, beer, wine, chocolate and tea. Many people avoid fruits and vegetables, especially the brassica group, which includes Brussels sprouts and broccoli, because of the bitterness they transmit. The brassica group produces glucosinates, red wine produces phenols, and citrus fruits produce flavonoids. Plants use bitterness as protection against predators. Bitter taste is a warning to people. Small doses of these substances can have health benefits in the fight against chronic diseases, but in large portions they are toxic.
Salt Flavor Receptors
People often crave salinity because sodium ions are essential for many body functions. Food salinity is mainly derived from sodium chloride (table salt). A pleasant salty taste arises when sodium ions enter the sodium channel on the surface of taste cells and mediate nerve impulses through the influx of calcium. A hormone called aldosterone increases the amount of sodium channels on taste cells when there is a sodium deficiency. The sodium channels on taste cells are also sensitive to chemical amiloride and differ from the sodium channels on nerves and muscles.
Sweet Taste Recipes
The desire of the body for a sweet taste may be due to the ability of sweet foods to provide a quick influx of energy. The sweet taste in food consists mainly of glucose and fructose, which are found in sucrose or sugar. However, the sweet taste can also come from non-carbohydrates such as aspartame, saccharin and some proteins. Sweet substances, like bitter substances, bind to receptors associated with protein, which leads to the activation of nerve endings.
Acid Carboxylic Acids
The sour taste is caused by acids called carboxylic acids. They evoke a sour taste in foods such as fruits, vinegar, dairy products and processed meats. They range from malic acid found in apples to lauric acid, the fatty acid found in coconuts. The function of the acid is to improve the nutritional taste and lower its pH level, which prevents any growth of microbes.
Acids also act as hardeners, especially for meat and fish. Initially, scientists explained the acidic taste by dissociation of acids in solution into hydrogen ions and anions, and only the sensation of hydrogen was responsible for the sensation of taste. However, this could not explain the different intensity of acidity. They may be associated with other variables, such as the number of carboxyl groups in the molecular structure of the acid.
In nature, there are many substances that affect taste. There are four basic tastes that can be perceived by the human language. It is bitterness, acidity, salinity and sweetness. A popular myth that is now debunked is that different areas of the language are involved in the perception of different tastes. In fact, all taste buds can feel all tastes, and taste buds are found on the entire surface of the tongue, as well as on the cheeks and upper esophagus.
Threshold substances for sour taste
Examples of acidic foods include lemon, spoiled milk, oranges, grapes, etc. Taste is measured and determined using threshold substances. Acidic taste is measured by the indicator of the acidity threshold of bitterness of dilute hydrochloric acid, which is equal to 1. Therefore, tartaric acid has an acidity index of 0.7, citric acid - 0.46, carbon dioxide - 0.06 compared with the threshold indicator of hydrochloric acid.
How is a sour taste perceived? The answer sounds a little difficult to understand: acidity is determined by the concentration of hydroxonium ions in the channels of ionic hydrogen. What is meant? Hydronium ions are formed from water and acid. The resulting hydrogen ions permeate the amiloride channels, allowing the detection of acidity. In addition to these mechanisms for detecting acidic taste, there are other mechanisms, such as the conversion of CO 2 to bicarbonate ions, facilitating weak acid transfer.
Sour tastants
Speaking about sour taste, people often recall lemons, with the mere thought of which a little salivation begins. What are the substances with an acidic taste at the chemical level? Here are some examples:
- acetic acid in vinegar;
- citric acid in citrus;
- lactic acid in lactic acid products;
- tartaric acid in grapes and wine.
It all depends on the concentration, and strong acids can be deadly to the body. Our usual food contains an acceptable level of concentration, for example, spinach, sorrel, some fruits and berries contain a substance with an acidic taste, like oxalic acid. The most common is citric acid, which is found in citrus fruits, as well as in strawberries, raspberries, gooseberries. Lactic acid is the result of lactic acid fermentation. More acidic properties are possessed by malic acid, which determines the acidic note of apples, cherries, quinces and passion fruit. The wine room looks like crystals. It can be seen in sediment at the bottom of the barrel or on the inside of a wine cork.
What other sour tastes are there? These are inorganic compounds such as carbonic and phosphoric acid, phosphoric acid, which gives an acidic taste to carbonated soft drinks. In the stomach, humans and all animals have hydrochloric acid; ants produce formic acid. Substances with a sour taste are very common in nature and are found not only in food, but also in living organisms themselves.