What Factors Affect Taste Perception?

Taste refers to the feeling that food stimulates the chemosensory system of the taste organs in the mouth of a person. The most basic tastes are sweet, sour, bitter, salty, and fresh. The tastes we usually taste are the result of mixing these five tastes.

Taste refers to the feeling that food stimulates the chemosensory system of the taste organs in the mouth of a person.

A suitable stimulus for taste is a soluble, flavorful substance. When the taste stimulus stimulates the taste buds with the solution, the taste buds convert the chemical energy of the taste stimulus into neural energy, and then pass along the glossopharyngeal nerve to the center of the brain and cause taste.

The most basic tastes are sweet, sour, bitter, and salty. The tastes we usually taste are the result of mixing these four tastes. Different parts of the tongue surface have different susceptibility to these four basic taste stimuli. The tip of the tongue is sweet, the front of the tongue is salty, the back of the tongue is acid, and the root of the tongue is most sensitive.

Taste sensibility is also closely related to the physiological condition of the body. For example, when hungry, the susceptibility to sweetness and saltiness is higher, and the susceptibility to acidity and bitterness is lower; after eating, the opposite is true. The susceptibility to acidity and bitterness is increased, and the susceptibility to sweetness and saltiness is reduced. Therefore, when you are hungry, you eat something fragrant, and when you are full, you do nt feel fragrant.

The sensibility of taste is closely related to the sense of smell. In the case of losing the sense of smell, such as when you have a cold, there is no taste in what you eat. It can be seen that incense and taste are inseparable. ^[1]

A The process of taste production is that taste substances stimulate the taste receptors in the oral cavity, and then are transmitted to the brain's taste center through a neural sensory system that collects and transmits information. Finally, the brain's comprehensive neural center system is analyzed to generate taste. Different taste sensations produce different taste receptors, and the forces between the taste receptors and the taste substance are not the same ^[2]

Front of tongue ^[2]

Biological mechanism of bitterness formation

Bitterness is the sensation caused by the irritation of liquids containing chemicals. The taste receptors are taste buds. The taste buds are oval in shape and are mainly composed of taste cells and supporting cells. The microvilli on the top of the taste cells extend toward the taste pores and come into contact with saliva. The base of the cells is innervated by nerve fibers. The formation mechanism of taste is that the bitter taste receptor protein distributed on the microvilli on the top of taste cells in taste buds is combined with the bitter taste dissolved in the liquid phase and activated. After intracellular signal transmission, the taste cell membrane is depolarized, which in turn triggers nerve cells. Post-synaptic excitement, excitatory signals enter the medulla nucleus along the facial nerve, glossopharyngeal nerve, or vagus nerve, replace neurons to the thalamus, and finally project to the lower center of the taste center after the central brain. After the integration of the nerve center, a bitter taste perception is finally produced ^3]

Of the four basic taste sensations, people have the fastest feeling of salty taste and the slowest feeling of bitterness, but in terms of their sensitivity to taste, bitterness is more sensitive than other taste sensations and is easier to detect ^[2]

Structure of matter:

Carbohydrates-sweet, acid-sour, salt-salty, alkaloid-bitter.

Water solubility of the substance:

To become a substance, it must have a certain degree of water solubility to have a certain taste. A substance that is completely insoluble in water is odorless, and a substance with a solubility less than a threshold is odorless. The higher the water solubility, the faster the taste is generated, and the faster it disappears. Generally, the substances exhibiting sour, sweet, and salty taste have greater water solubility, while the substances exhibiting bitter taste are generally water soluble.

Temperature:

Generally, as the temperature rises, the sense of taste is strengthened. The most suitable temperature for the sense of taste is 10 ~ 40 , especially 30 is the most sensitive. Above or below this temperature will become dull. Temperature also has a significant effect on the threshold for becoming a substance.

25 ° C: 0.1% sucrose, 0.05% table salt, 0.0025% citric acid, 0.0001% quinine sulfate

0 ° C: sucrose 0.4%, table salt 0.25%, citric acid 0.003%, quinine sulfate 0.0003%.

Feeling parts of taste

We experience taste through taste buds. Each taste bud contains 50 to 150 receptor cells with different tastes. Each taste bud can feel all the basic taste senses. Therefore, no matter how the taste buds are distributed, the sensitivity of different areas of the tongue to different tastes is almost the same.

Taste interaction

When two identical or different substances enter the oral cavity, they will change their taste in the morning, which is called the interaction of taste.

A taste of the contrast phenomenon:

It refers to the phenomenon that two or more flavoring substances are properly blended to make the taste of a particular flavoring substance more prominent. For example, adding 0.15% sodium chloride to 10% sucrose will make the sweetness of sucrose more prominent, adding a certain amount of sodium chloride to acetic acid will make the acidity more prominent, and adding sodium chloride to monosodium glutamate will make umami taste More prominent.

Multiplicative effect of B flavor:

It refers to the synergistic effect of taste when two substances with the same taste enter the oral cavity, the taste intensity of which exceeds the sum of the taste intensity of the two alone. Glycyrrhizin itself is 50 times sweeter than sucrose. But when used together with sucrose, the sweetness at the end can reach 100 times that of sucrose.

C flavor killing effect:

It refers to the phenomenon that one taste substance can weaken the taste intensity of another taste substance, also known as the antagonistic effect of taste. Such as the interaction between sucrose and quinine sulfate.

D Tone Change Effect:

Refers to the phenomenon that two flavoring substances affect each other and cause their taste to change. I just ate a bite of water after eating bitter things, and the water was sweet. Bitterness is produced when you eat sour after brushing your teeth.

E-flavor fatigue effect:

After being stimulated by a taste substance for a long time, the phenomenon that the amount or intensity of stimulation is reduced is felt. ^[2]

Pathogenic mechanism

Drugs affect taste receptors by directly or indirectly causing taste disorders. Known pathways may have the taste of the drug itself; damage to taste receptors through direct or secondary processes (such as acid through gastroesophageal reflux); immunosuppression and Effects of related sequelae (such as oral candidiasis); impulsive dissemination of disturbed neurons (such as demyelination of peripheral neurons by affecting calcium influx); altered neurotransmitter function; higher-level senses related to taste Changes in the information process; dryness of the oral mucosa restricting the passage of chemicals through the receptor site; antipsychotic drugs can cause dry mouth syndrome and affect taste; change the production and chemical composition of saliva and mucus components, although the basic role of saliva is to provide oral moisture It also acts as a lubricant, but it is necessary for buffering acid and alkali and adding soluble chemicals to taste receptors. In patients with low taste function caused by drugs, serum zinc concentration is reduced in about 50% of patients. The reason may be Is a drug and its metabolites forming a water-soluble complex with zinc, or some drugs increase the excretion of zinc in the urine, from Zinc deficiency leads to the body and cause taste disorders.

Prevention and treatment

Prevention should start in many ways. First, you can change your diet and eat more foods rich in zinc, such as oysters, pork blood, pork liver, meat, sesame, pine mushrooms, and soybeans. Second, determine the blood zinc concentration. If the blood zinc concentration is low, you can increase the serum zinc concentration by taking a zinc preparation. Third, if the drug that causes taste disorders is clear, it should be used under the guidance of a doctor to see if it can change the taste disorder. If it is not effective, switch to a drug with the same effect and low or no effect on taste disorders.

Antidepressants

Amitriptyline, clomipramine, norpromazine, doxepin, and imipramine in tricyclic antidepressants; flumetamine, a serotonin reuptake inhibitor

Antipsychotics

Phenytoin, benzodiazepines, lithium salts

Sedative hypnotics

Triazolam, flunazepam, fluoxetine, zopiclone

Antitremor paralysis

Selikilin (Umax), L-Dopa, etc.

Antimicrobials

Amoxicillin, metronidazole, tinidazole, dirithromycin, clindamycin, azithromycin, norfloxacin, ciprofloxacin, ofloxacin, etc.

Antifungal

Terbinafine, Iconazole, Fluconazole, Griseofulvin, etc.

Antivirals

Acyclovir; anti-HIV nucleosides, such as zidovudine; protease inhibitors, indinavir, etc.

Anti-inflammatory analgesics

Diclofenac, Meclofenamic Acid, Ibuprofen, Diclofenac, Indomethacin

Hypoglycemic agents

Metformin, acarbose, voglibose; sulfonylureas, such as glipizide

Antihypertensive drugs

Angiotensin-converting enzyme inhibitors, such as captopril, enalapril, etc .; angiotensin 2 antagonists, such as losartan, losartan, etc .; various calcium antagonists, such as axandridine; Class: Isosorbide nitrate; others, diazoxide, guanidine

Antihyperlipidemic drugs

Statins, such as simvastatin; probucol

Antiarrhythmics

Amiodarone, bradycardia, encarne, lidocaine injection, etc.

Diuretics

Furosemide, acetazolamide

Antiasthmatic

Ipratropium bromide

Antiulcer

Omeprazole; bismuth agents, such as potassium bismuth citrate

Hypothyroidism

Sulfuracils, such as methimazole, propylthiouracil

Hypothyroidism

Potassium iodide (long-term use: metallic smell in the mouth), iodized oil gel pill (poisoning symptoms: copper smell in the mouth)

Antirheumatic drugs

D-penicillamine

Antihyperuricemia

Colchicine

Anticancer drugs

Cinerpe, doxorubicin, capecitabine, Xeloda, etc., 36% to 71% of cancer patients undergo taste changes after chemotherapy

Vitamins

Vit D2, D3 (early symptoms of poisoning: metallic taste in the mouth, etc.)

Heavy metals and their preparations

Arsenic, Mercury, Lead (Symptoms of poisoning: metallic taste in mouth)

Disinfectant

Potassium permanganate (poisoning symptoms: metallic taste in the mouth)

In addition, thiothiourea antituberculosis drugs and iron sorbitol injections may also cause taste changes in the mouth (metallic taste)