Science of cooking

Cooking is the arrangement of food supplies. It is cultural and depends on the ressources available and the climate the people are in. It evolved a lot through time and regions. Spicy, sweet, salty, tasty, every person has a different affinity with meals. However, what they all have in common, they respond to a primary need amongst humans: feeding. Let’s explore all the elements involved from our needs to the feasts we enjoy.

Food as a source of energy

What we call food is any element that provide an energetic supply to our body, our organism [1].

The vast majority comes from either animals or plants but some have a mineral (salt), a fungal (mushrooms, yeast), a bacterial (yogurt) origin.

Food can be cooked or prepared raw which will change the kind of intake it will provide. While cooking eliminates germs or parasites thanks to heating [2], its other benefits are to change the flavour, the texture and the palatability (the sensation on the palate).

Why do we eat such a wide variety of food? Because our organism has specific needs that only one kind can hardly fulfill.

The need of our body

The body needs nutrients. Nutrients are molecules produced by assimilated food [3]. We have three categories with different functions:

• Proteins: part of the human body composition (muscles, skin, bones, hair, etc.), they play a part in major physiological processes like antibodies [4] or hormones production. They also are the only nitrogen production for our body.

• Lipids: the energetics nutrients. They insure our organs and cells functioning, being a part in the composition of the cells membranes. They help producing some hormones and play a part to transport those hormones as well as proteins and vitamins in our blood.

• Carbohydrates: non-essentials and can be produced with other nutrients (at the contrary of proteins and lipids). The muscle, nerves and brain cells will use them as a reserve of energy.

Another necessary nutrient is water. It acts as a solvant to dissolve salt and sugar and creates a medium propice to chemical reactions. It also helps the transport of the other nutrients. It is contained in almost every food.

The willing to ingest food is determine by one of our nine senses: taste.

5 basic tastes

We distinguish 5 different basic tastes [5]:

• Sweetness: sugars, some alcohols (like glycerol), some proteins, some saponins (like artificial sweetener) produces sweetness. We measure it relatively to sucrose.

• Saltiness: presence of cations (Na+, K+ Li+) triggers saltiness. We measure it relatively to sodium chloride (salt).

• Sourness (acidity): like saltiness, ion enters taste receptors and cause electrical response. We measure it relatively to hydrochloric acid.

• Bitterness: the one taste that feels unpleasant. It is the most sensitive of our tastes. We measure it relatively to quinine, a bitter medicine.

• Savoriness (umami): glutamates (an amino acid) and its interaction to our taste receptors is responsible for savoriness.

Some elements seems to point out a sixth taste, the fat taste, in relation to fatty acids [6]. However it doesn’t reach a consensus yet.

But what tells us which taste we feel?

A chemical reaction to stimuli

Taste is a chemoreception, meaning the sensory receptors transform a chemical element into a biological information.

Our mouth determines those tastes, especially our tongue where most taste receptors are. The tongue is composed with papillae themselves composed with the taste receptors mentioned before, the taste buds.

We have four different kind of papillae named according to their form: fungiform, foliate, circumvallate and filiform papillae. However, only the first three contains the taste buds.

This taste buds are called G protein-coupled receptors. We distinguish 2 kind of them [7][8]:

• Type 1 with the TAS1R1 (for savoriness), TAS1R2 (for sweetness) and TAS1R3 (for savoriness and sweetness) receptors.

• Type 2 with the TAS2R (for bitterness) receptors. We have 25 different receptors from that type.

You may have noticed that I emphased twice about bitterness. It is because our ability to detect bitter food is a very important survival ability we developed.

A survival adaptation

In nature, most poisons you can find on plant leaves have a bitter taste. So, according to natural selection, the individuals with a taste for bitterness more developed have higher survival chances than individuals simply more resilient to those poisons. Then they will pass this characteristic to their offspring.

However, some plants have a bitter taste but are not poisonous. So having such a developed palate would keep us from eating those plants. It means that it is a constraint except for animals that can eat other food like carnivores or omnivores like us, humans [9].

So no matter what kind of food you eat, be sure to have all the nutrients you need and try to feel the glutamates in your favorite meal.

References

[1] Food | Definition & nutrition | Britannica.com, https://www.britannica.com/topic/food

[2] Food Poisoning | NIDDK, https://www.niddk.nih.gov/health-information/digestive-diseases/food-poisoning?dkrd=/health-information/digestive-diseases/foodborne-illnesses

[3] Florence Pujol, Les 100 mots de la diététique et de la nutrition, Que sais-je, 2010, ISBN 9782130616412

[4] All You Need Is Science, Viruses: better understanding for better protection

[5] Ikeda K. (2002), “New Seasonings”, Chemical Senses, Volume 27, Issue 9, November 2002, Pages 847–849, https://doi.org/10.1093/chemse/27.9.847

[6] Keast Russel R.J.; Costanzo Andrew (2015), “Is fat the sixth taste primary? Evidence and implications”, Flavour volume 4, Article number: 5 (2015), https://doi.org/10.1186%2F2044-7248-4-5

[7] Adler Elliot; Hoon Mark A.; Mueller Ken L.; Chandrashekar Jayaram; Ryba Nicholas J.P.; Zuker Charles S. (2000), “A Novel Family of Mammalian Taste Receptors”, Cell, Volume 100, Issue 6, p 693-702, March 17, 2000, https://doi.org/10.1016/S0092-8674(00)80705-9

[8] Nelson Greg; Hoon Mark A.; Chandrashekar Jayaram; Zheng Yifeng; Ryba Nicholas J.P.; Zuker Charles S. (2001), “Mammalian Sweet Taste Receptors”, Cell, Volume 106, Issue 3, p 381-390, August 10, 2001, https://doi.org/10.1016/S0092-8674(01)00451-2

[9] Glendinning John I. (1994), “Is the bitter rejection response always adaptive?”, Physiology & Behavior, Volume 56, Issue 6, December 1994, Pages 1217-1227, https://doi.org/10.1016%2F0031-9384%2894%2990369-7