Flavoursome foods at home

What can you sense as you sit in front of this screen? First of all, you can sense the light coming from the screen. It shines into your eyes and your eyes send messages to your brain. The messages are in the form of tiny electric currents and they travel along nerves, which look like white wires. Inside the brain, the messages are put together to give you the sense of sight. This sense allows you to read these words, look at your keyboard or out of the window.

The second sense you are aware of is your sense of hearing. The spinning of the fan inside your computer makes sounds, which travel out from the case in all directions. Those waves that enter your ears make nerves send messages to your brain to give you your sense of hearing.

The third sense you may be aware of is your sense of touch. Just hold your mouse to feel its smooth surface. There are two more senses, which you use particularly at special times. They are your sense of smell and your sense of taste. You use them every mealtime.

When food is cooking, little particles of the food break away and travel through the air. High inside your nose are patches of skin which are sensitive to these particles. When you are breathing normally, the air does not pass these patches so you do not really smell the air. If you want to smell the air, you sniff. This action makes the air rise right up inside your nose and flow over the sensitive patches. Just as with the other senses, nerves send messages to the brain and you become aware of the smell.

On your tongue are thousands of tiny patches called taste buds. They are sensitive to taste as their name suggests. Tastes, like smells, are due to tiny particles, which break off from the food. There are four basic kinds of taste. They are salt, sweet, sour and bitter. Each one is sensed by a particular area of the tongue. Sweetness is sensed near the tip, while saltiness is sensed close by on each side. Sourness is sensed further back along the sides and bitterness is sensed in the middle of the tongue at the back.

Smell and taste work together. If you do not believe it, just hold your nose and chew a pickled onion for a half a minute. You will probably taste very little. Now let go of your nose and the taste of your food will be much stronger.

The sense of taste is really a way of keeping you safe. If something tastes foul you spit it out. The foul taste is a danger warning. It tells you the substance could be harmful to eat.

Do nerves just go from the sense organs, like the eye and the ear, to the brain?

No. There are nerves that go from the brain to all the muscles in your body. When your sense organs send messages to the brain, your brain may send out messages to your muscles. For example, you may see an apple in a fruit bowl and decide to eat it. Your brain then sends messages to your muscles to make them work. When the muscles work they make you walk over to the fruit bowl, pick up the apple and start to eat.

Do animals have the same senses as us?

Yes, they do. Some of their senses may be better than ours and some of their senses may be worse. For example a mole, which lives underground, is almost blind. It has a much worse sense of sight than we do. A dog has a much stronger sense of smell than we do but has a poorer sense of sight. Some animals have unusual sense organs. A snake called a pit viper has sense organs, which can detect the heat coming from an animal's body. This allows the snake to hunt in the dark to find animals such as mice. When any snake sticks out its tongue, it collects particles on its surface then draws its tongue back into its mouth and presses it into a tasting patch in the roof of the mouth. The tongue is used in a process to taste the air not smell it. You may see that some fish have fleshy 'fingers' which hang down from their mouths. These 'fingers' have tasting patches on them. When the fish are in the water, they sometimes swim close to the bottom of a pond or river and taste its surface to find food.

Why does food go bad?

Everything is surrounded by tiny living things called microbes. Some of them may enter our body and make us ill. We call them germs. Many do not affect us but when some land on food they feed on it and make it go bad. Foods which have water in them, like meat, are particularly in danger of being attacked by microbes because the microbes need water to feed and breed. Other food, such as biscuits, contains little water and can be kept fresh and edible a long time if covered up.

How can meat be stopped from going bad?

In the past large amounts of salt were added to meat. This stopped the microbes feeding and breeding but it also gave a strong salty taste to the food. Today meat is prevented from going bad by freezing. Microbes cannot feed and breed quickly when the meat is frozen so the food stays fresh. If you look on a fishmonger's counter you may see the fish resting on chunks of ice. This keeps the fish meat cool and fresh while also letting people look at the fish and chose one for their meal.

What is the difference between a herb and a spice?

Both herbs and spices produce substances that make food tasty. Generally, herbs are plants which can grow in places with cool, wet climates such as Great Britain. Spices are produced by plants which grow in places with warm climates that may be either dry or wet.

Is the whole of the herb plant used in cooking?

No. The leaves of most herbs are used in cooking. Examples of herb plants which have leaves used for flavouring are mint, sage, parsley and marjoram. Horseradish is a herb in which only the root is used. Garlic is a herb in which a bulb is used. Garlic is unusual in having an edible bulb. Most plants have bulbs which are poisonous.

Which part of a plant is used to make a spice?

Many spices are produced from seeds. Plants which produce seeds that are used as spices are coriander, cumin and mustard. Cinnamon is produced from the bark of the cinnamon tree. Ginger is produced from the underground stem of the ginger plant. Cloves are the unopened flower buds of the clove tree.

What are the spices in curry powder?

There may be between twelve and twenty different spices in a curry powder. The main spices are cayenne, cloves, coriander, cumin, fenugreek, ginger, mace, pepper and turmeric.

Where does salt come from?

Salt does not come from a plant. It forms a mineral in the ground. The mineral is dug out of the ground and broken up to make salt grains. Salt is also found in sea water. In some hot parts of the world pools of sea water are made. The pools are allowed to dry up. When they do this, the salt is left behind. The salt you put on your food may come from the ground or the sea.

In the past, before there were many ways to keep food fresh, meat could start to taste bad after a short time. Although the meat did not taste very well, it was not too harmful to eat so cooks made the meat taste better by adding herbs and spices. Today, all meat that is sold is fresh and edible but herbs and spices are still used as they make the food taste delicious.