Bitter, Sweet, Salty, and Sour: Senses of Taste Quiz

Answer: The flavor is actually mostly related to smell.

Many of us associate the flavor of food with the taste on our tongues, but in reality, the sense of taste is a minor part of how we interpret or identify food. Rather, the flavor of food is mostly based on the sense of smell which can detect thousands of differences in flavors. If you have ever had a bad cold with a stuffed nose you might have noticed food tasting very bland. The texture of food can be important to our enjoyment but it does not contribute much to the flavor. As for flavor being the same, food often tastes very different from person to person.

Answer: True

There are no specialized regions on the tongue...and you can still see the inaccurate map appearing in textbooks! Raise your hand if you were ever shown a picture of the tongue with sweet being at the tip and bitter being in the back. This map could not be more wrong. The reality is the entire tongue can equally detect taste with a specialized type of cell we will talk about in question three.

Answer: Gustatory cells

Gustatory cells contain the taste buds that are sensitive to several chemicals within the food we eat. Each gustatory cell is able to detect the presence and the intensity of all the basic tastes. There are specific chemicals in salty, sweet, bitter, and sour foods that stimulate the gustatory cell and once a threshold is reached the cell will transmit a signal to the brain that it detects the sensation.

Answer: Ion channels

Ion channels detect salty sensations. The most common are sodium, potassium, and calcium. In particular, they use voltage gates which will get triggered if the salt ion concentration reaches a high enough level. This conversion of chemical to electrical energy stimulates the taste region of the brain. Salty is an important taste as we need these ions to keep the body's pH in balance and our nerves use ions to send signals.

Answer: Umami

Japanese chemist, Kikunae Ikeda, first identified umami in 1908. The term "umami" translates as "pleasant savory taste". On a chemical level, the amino acid glutamate has receptors in the gustatory cells. In particular, free-floating glutamate is a strong trigger for the umami sensation. The umami flavor is associated with meat, cheese, and tomatoes. The umami flavor is very important as it signals to the body that protein is being ingested which is both an energy source and a building block for enzymes. The body responds by releasing enzymes in the stomach and intestines.

Answer: Gustatory cortex

The gustatory cortex is the region of the brain that first responds to the taste sensation. The location of the gustatory cortex is partly in the frontal lobe and partly in the insula lobe. The stimulation of this region causes the body to prepare to break down food or warn of potential danger. The intensity of the stimulation also can be detected based on the number of gustatory cell actively reporting a sensation.

Answer: No

The temperature of food often changes how it tastes. Like on the skin, the mouth has taste receptors that inform the brain what temperature a food item is. Chemicals like capsaicin actually trick the temperature receptors into believing the mouth is burning.

In reality, there is no damage being done. The capsaicin will numb the receptor for a while but once the effects wear off the tongue is good as new. It is possible to desensitize the receptors to the burning sensation with repeated exposure over time, thus explaining why people who frequently eat spicy food do not experience the same level of "heat" as people who avoid spice. Capsaicin, primarily found in chili peppers, acts as the plant's defense mechanism. Capsaicin is also found in pain relief rubs since the chemical causes the pain receptor to become hot and then go numb for a time.

Other spicy chemicals include piperine in black pepper and allyl isothiocyanate in mustard and radishes.

Answer: Mouthfeel

Mouthfeel is, like it sounds, how a particular food feels in the mouth. Custard has a different feel than crunchy carrots. It is worth noting that our mouths can detect very subtle changes in food. Both beer and wine use the term mouthfeel to differentiate the subtle difference between different beverages. By the way, bolus simply means a small mass of something and is used to describe a mouthful of food.

Answer: To protect the body from a wide variety of toxins.

Many toxins and poisons have a bitter flavor. One particular group of chemicals that trigger a bitter taste is the alkaloids, like caffeine or strychnine. The gustatory cells have a very low threshold to many of these alkaloids which makes sense as it often does not take much of the compounds to poison the body. Interestingly, the larger the alkaloid molecule is, the greater the bitter sensation usually is. While bitterness is a warning mechanism to the brain, humans have evolved a liking for many bitter foods like chocolate and coffee.

Answer: Spoiled food often tastes sour.

The acidity of food creates a sour sensation triggering the hydrogen proton (H+) receptors in the gustatory cells. Food spoilage results from bacterial breakdown of the food and creates a by-product of lactic acid. While lactic acid itself is not harmful, often the bacteria creating the acid are, thus resulting in sour being a defensive taste mechanism. Good bacteria are responsible for pickled food, including sauerkraut and kimchi.

These bacteria also release lactic acid which is why they are sour, but in this case, the healthy bacteria actually help prevent the harmful bacteria from growing on the food.

This is why pickled foods can stay edible for a long period of time without refrigeration. Pickled fish anyone?