Молекулярная гастрономия для креативных шеф-поваров (англ. язык) - страница 100

Молекулярная гастрономия для креативных шеф-поваров (англ. язык)

These molecules are neutral, and do not interact with water because they are not attracted to the

water molecules, so they will not preferentially mix.

For example, oil does not mix with water. This can easily be seen if oil is added to water, the oil (which

is less dense) will float to the top and not mix with the water. The hydrophobic oil molecules will “stick

together” with special bonds (called hydrophobic interactions), and the hydrophilic water molecules will

“stick together” due to the hydrogen bonds.

If the mixture is vigorously shaken, the force of shaking will break the two liquids into smaller droplets,

and the tiny droplets of oil will temporarily disperse in the water. However, as soon as this force is

stopped, the oil droplets are free to move around and combine, and as the droplets become bigger

again the two layers separate out.

In order for a mixture of oil and water to stay stably dispersed, a special sort of molecule needs to be

added. These molecules are called tensioactive molecules. They possess a hydrophilic head and a

hydrophobic tail, or in simpler terms they have one end of their molecule that is soluble in water, and

one end that is soluble in oil. The principal is that these molecules surround the tiny oil droplets by

making contact with their hydrophobic parts, leaving their hydrophilic parts to contact the water part

and keep the fat droplets very dispersed. Many foods contain such tensioactive molecules...

contact the water part

and keep the fat droplets very dispersed. Many foods contain such tensioactive molecules which are

commonly used to stabilise oil/water mixtures.

Role in food:

Water is the most abundant molecule in nature. Most foods contain primarily water (eg. vegetables

contain very high amounts of water, as do meat and fish, and diary products like milk and eggs). Many

of these substances therefore lose mass if they are cooked at high temperatures, because the water

contained will evaporate, making the cooked mass less than the raw mass.

In food, water is often perceived as “tenderness”. Hard cheese contains much less water than soft

cheese, and is therefore less tender. A rare steak (where little liquid has been evaporated during the

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