Why Common Salt Tasts Bitter.

 

 Why common Salt Tastes Bitter.

P.K.Ghatak, MD

No.42.

Every dining table has a permanent place for a saltshaker. When sprinkled on food, each white crystalline salt grains dazzle food and add favor to food. If the same dish cooked without salt and no saltshakers are available no one would take a mouthful of food because it turns tasteless.

The difference is all due to Salt which is Sodium Chloride. The common salt contains a small amount of additional chemicals to prevent caking of and also supply daily iodine requirement.

The taste of Sodium chloride is salty but that is not all, salt may appear bitter, sweet or even sour and metallic. In addition, salt enhances other primary tastes and eating experience.

Sodium chloride dissolves in saliva and sodium ion enters the salt taste buds through Na+ channels and trigger an electrical impulse which is carries first to thalamus and next relayed to taste center located in the Anterior Insular Cortex and posterior part of Brodmann area 3B. Here integration of taste and smell of food takes place. Additional nerve fiber connects to Orbital Frontal cortex where enjoyment of a particular food takes place. By this mechanism we appreciate of taste sensation of salt.

The basic mechanism is the same for the remaining primary taste senses - sweet, sour, bitter, and umami (savory), triggered by specific taste molecule specific for that taste.

Salty food taste Bitter:

Some physicians order healthy salt for their cardiac patients. Healthy salt contains added Potassium chloride. Potassium chloride is bitter in taste.

If unknowingly salt is added twice while cooking a small dish, the highly concentrated salt tastes bitter. In nature all herbivorous and omnivorous animal consider bitter as poison and avoid bitter tasting food. This safely feature programmed in our brain to make food unpalatable and prevent illness.

Salt has a Metallic Taste:

Common salt by regulation must contain a certain amount of added Potassium iodide. That regulation has drastically reduced the incidence of Thyroid Goiter which was commonly prevalent in rural areas away from the seacoast due to chronic iodine deficiency. Potassium iodide has a metallic smell and taste.

Salty food taste Sweet:

It is known to most, that if one drinks mouthful of water a few times after eating something bitter then gradually a sweet taste emerges. Just washing away an unpalatable sensation brings sweet sense.

When water molecules dilute sodium from the local taste buds, the bitter or salty taste is replaced by a mild sweet sensation.

Salty food taste Sour:

It may be due to many reasons which either results in abnormal sensual perception by the brain or altered health of the surface cells, including taste buds of the tongue. Neurological conditions – Alzheimer disease, Multiple Sclerosis and Parkinson's disease.

Local condition of the mouth and tongue: -   Diabetes mellitus, Gastroesophageal reflux, dry mouth and poor oral hygiene and alcohol and smoking.

Salt enhances other tastes:

Each variety of taste has its own specific taste bud and responds to that taste and at the same time salt enters Na+ channel and magnify the electrical signal, as a result sweet tastes sweeter and bitter taste less bitter. (has signal suppressor effect for bitter). And the same effect is seen in the remaining tastes.

Footnote:

Anticaking agents:

Caking of common salt occurs because moisture present in the air is absorbed by salt and gets dissolved in water, then return to crystalline sate. During recrystallization it adhere to other salt granules and forms clumps. To prevent caking several chemicals are added by different manufactures, namely -

Sodium ferrocyanide. It decreases solubility of salt by modifying the surface of salt crystals and prevent liquification. Manufacturers use yellow prussiate of soda, an old name instead of sodium ferrocyanide because people associate Cyanide with a deadly poison and would not use that brand. Ferrocyanide is tasteless and odorless.

Calcium silicate. It absorbs moisture avidly (hygroscopic) and oil from air before salt has gotten a chance to mix with water. Calcium silicate is tasteless

Sodium aluminosilicate. It is a hygroscopic material and tasteless.

Calcium carbonate. It is a hygroscopic agent and taste chalky and tasteless.

Magnesium carbonate. It is hygroscopic, chalky and tasteless.

Natural anticaking materials. Rice grains and corn starch and silica.

Variety of salt.

Rock salt. It is made of entirely NaCl and mixed with minimal number of impurities like gypsum, dolomite, calcite, and quartz.

Sea salt. Composition of Sea salt. Sodium 31%. Chloride 55%, Sulfate 7%, Magnesium 4%, Calcium and Potassium 1 % each.

Himalayan salt. NaCl 98% and traces of minerals like calcium, magnesium, potassium and iron, Iron gives its pink color.

Himalayan Black salt. NaCl 98%, very small amount of sodium sulfate, sodium bisulphate, and iron sulfide and traces of minerals. Iron sulfide gives it pungent odor.

Koshar salt. NaCl plus anticaking Sodium ferrocyanide and no Iodine. It comes in large flakes and popular with professional chefs.

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