Food and Its Соnstituents. Пища и её влияние на организм человека. Учебное пособие

galactose [gq'lxktqus], sucrose ['sHkrqus], lactose ['lxktqus], maltose

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[vq'raiqti]; sweet (! ', % ") – sweetness; to cook (" ")

– cookery

III. .

TEXT D. CARBOHYDRATES Chemistry

There are several types of carbohydrates, but they all contain three elements: carbon, hydrogen, oxygen. Oxygen and hydrogen are present in the same proportion as in water (H2O), hence the term “hydrate”.

Sources

Carbohydrates are produced mainly by plants during the process of photosynthesis, in which the following reaction occurs: carbon dioxide (CO2) + water (H2O) + energy from sunlight = carbohydrate + oxygen (O2)

Classification of carbohydrates

There are three main carbohydrates: monosaccharides, disaccharides and polysaccharides.

Monosaccharides

These are sometimes called simple sugars, as they are the common base units from which other carbohydrates are built, and they are chemically sugars. They are soluble in water and of varying sweetness. There are three main monosaccharides:

Fructose

Fructose is sometimes called fruit sugar because it is found

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mainly in fruits, plant juices, and honey.

Glucose

Glucose is the form of carbohydrate that the body uses for energy, and all other carbohydrates are turned into glucose during digestion. It is found into ripe fruits and some vegetables, e.g. onions, beetroot.

Galactose

Galactose is found in the milk of mammals, where it forms part of the milk sugar, lactose.

Disaccharides

These are sometimes called double sugars, as they are composed of two monosaccharide units joined together. They are soluble in water. There are three main disaccharides.

Sucrose

It is formed from one unit of glucose and one unit of fructose. Sucrose is used in cookery, and is obtained from cane and beet sugar.

Lactose

Lactose is formed from one unit of glucose and one unit of galactose, and it is found in the milk of mammals, to supply the infant with a source of energy.

Maltose

Maltose is formed from two units of glucose. It is sometimes called 'malt sugar', and is found in cereals such as barley, where it is formed during germination.

IV. .

1.Why does the body require carbohydrate?

2.What chemical elements make up carbohydrates?

3.What is photosynthesis and why is it important?

4.Name three monosaccharides and give their sources

5.Name three disaccharides, describe their composition, and give their sources.

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32

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Salsa is the spiciest Spanish sauce.

Plastic cutting boards are less porous then wood and are far less likely to harbor bacteria.

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1.Some research have shown wooden boards are far ……..... (good).

2.Don’t worry. The situation isn’t so bad. It could be ……….. (bad).

3.It’s very stuffy here. You should ventilate the kitchen

……………. (often).

4.As broiling is a way of cooking without added oil, it is ……..……. (popular) in low-fat diets.

5.Boiling is ……………. (cheap) method of killing bacteria.

6.To make …………..….….. (smooth) sauce, all the vegetables are processed and blended.

7.At first I thought it would be tasty, but it was ………. (bad) of all.

8.It is ……………. (easy) to be cut with a dull knife, because more pressure is needed to make a cut.

9.What is …………………...……. (good) dish you have ever eaten?

10.They needed …………………. (much) fuel for this engine.

11.They were designing …………...… (new) blades for the turbine.

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cereal ['siqriql], dextrin ['dekstrin], glycogen ['glaikOuGqn], pectin ['pektin],

34

cellulose ['seljulqus], gel ['Gel], liver ['livq], muscle ['mAsl]

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III. .

TEXT E. POLYSACCHARIDES

These are formed from a varying number of monosaccharide units - the prefix “poly” means “many”. There are five main polysaccharides.

Starch

Starch is formed from many glucose units joined together like links in a chain. It is formed during photosynthesis in plants particularly in root vegetables, cereals, and pulses. During digestion, the chains of glucose units are broken down into smaller chains, then into disaccharides and finally into single glucose units, which are absorbed into the blood.

Dextrin

Dextrin is formed when foods containing starch, e.g. bread, are baked or toasted. The dextrin forms part of the crust on such foods.

Cellulose

Cellulose is formed by plants from glucose units joined together in such a way that a strong, structural material is produced. The plants use this for stems, leaves, husks of seeds and bark.

Pectin

Pectin is a complex polysaccharide formed by some plants, e.g. plums, apples, in their fruits and roots. It forms gel in water and is responsible for setting jam.

Glycogen

Glycogen is formed after digestion in humans and animals. Some glucose is turned into glycogen for temporary storage in the liver and muscles. When energy is required, it is turned into glucose.

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Carbohydrate requirements

Carbohydrate should be used in preference to protein as an energy supplier, so that protein can be used for body growth and repair. Proteinand carbohydrate-rich foods are usually eaten together for this reason, e.g. meat and potatoes, bread and cheese.

If someone eats more carbohydrate than the body requires, the excess is converted into fat and is stored under the skin. This is one of the major causes of obesity.

IV. .

1.Name five polysaccharides, describe their composition, and give their sources.

2.What is the reason of eating together protein-.and carbohydraterich foods?

3.What happens if too much carbohydrate is eaten?

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36

- Present Indefinite, Past Indefinite, Present Perfect

V. .

1.Indians often ………...................... (to prepare) marinades with yogurt and spices.

2.Meats and fish ……….. (to be) the most common smoked foods.

3.The process of marinating …………….. (to last) seconds or days.

4.Stewing ………… (to be) a popular method of preserving meat till the middle of the 20th century.

5.Unfortunately hot smoke …………...………….. (not / penetrate) far into meat and fish.

6.The cereal foods ………………… (to play) and continue to play an important role in world history.

7.Toast ……….. (to be) a common component of many breakfasts.

8.For most of history, most cookbooks ….………... (not / to specify) the amount of food exactly, instead talking of “a nice leg of spring lamb” or a piece of butter “the size of a walnut”.

9.The sugar beet ………………………………….…….. (to spread) from Italy to northern Europe.

10.Salt pork and salt beef ………………. (to be) common foods for sailors before the days of steam engines.

11.Hot-smoking ……………………………………...… (to involve) holding the food directly above the fire.

12.Since ancient times salt …………………………………... (to be) the most popular chemical preservative.

13.Egyptians…..…… (to use) honey for the mummification process.

14.By the 15th century Venetian merchants ………………………

(to succeed) in establishing monopoly on sugar and ………………

(to keep) its cost quite high.

15.Phenol in wood smoke …..…………… (to slow) bacterial grows.

VI.

.

37

1. The purpose of sugaring is to prevent food spoilage.

………………………………………………………………...……

2. Jellied eggs are a delicacy in China

………………………………………………………………..……..

3.Drying was perhaps one of the first methods of food preservation

…………………………………………………………….…………..

4.In Italy spaghetti is longer than in other countries.

………………………………………………………………...……

5.Wood smoke compounds act as preservatives.

………………………………………………………………………...

6.Marinades contain herbs and spices.

………………………………………………………………………...

7.The process of marinating makes the food tastier and easier to

chew and digest.

………………………………………………………………………...

8.Reaction between creatine in muscle meats and amino acids caused by flame cooking, produces cancer-causing agents.

………………………………………………………………………...

9.Pickling began as a way to preserve food for out-of-season use and for long journeys, especially by sea.

………………………………………………………………………...

10.More than 300 years ago Alexander the Great brought sugar from India to Europe.

………………………………………………………………………...

11.The French and English royal courts used maize starch to powder wigs.

………………………………………………………………………...

12.The need for sugar has increased with the advance of civilization.

………………………………………………………………………...

13.People have enjoyed honey as food from the remotest times.

………………………………………………………………………...

14.Scientists have discovered many vitamins but there role in nutrition have not been determined yet.

………………………………………………………………………

15.Experiments have shown canned foods to be as healthy as any

form of preserved food.

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………………………………………………………………………

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II. .

1.Water can also be called a nutrient, as it is vital ….. life.

2.Our bodies are composed ….. millions of cells.

3.Protein can also be used to provide the body ….. energy.

4.The protein molecules are made …... ….. small units joined together like links in a chain.

5.This means that amino-acids must be obtained ….. foods, as they cannot be made ….. the body.

6.Fats are solid ….. room temperature.

7.Starch is formed ….. many glucose units joined together like links in a chain

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1. Different combinations of the same elements have different

39

properties.

2.Fats and oils are the same in their chemical nature.

3.They perform the same function in nutrition.

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1.Vitamin E, like vitamin K, is fat soluble.

2.It is likely that the new type of stores will be more comfortable.

3.Unlike proteins fats cannot be dissolved in water.

4.This substance looks like protein.

IV. .

1.The word “vitamin” ……….... (to mean) very “important for life”.

2.The transfer of population from rural regions to towns ……...……. (to continue), and the nature of the food supply

………….…. (to change).

3.He ………. (not / to seem) to be familiar with the experiments of other scientists.

4.Among common carbohydrates ……….... (to be) sugar and starch.

5.After that they …………………….…. (to begin) their experiment.

6.The modern food industry ……………….. (to rely) far more on technology then on human labour.

7.Science …………. (to make) many major advances this century.

8.Scientists ………………. (to make) some fundamental discoveries in the 18th century.

9.The modern food industry is the result of changes that

…………… (to occur) over the last 150 years.

10.Food processing ………..…. (to be) the method used to transform raw ingredients into food..

V. .

1.Fats and oils come from both animal and plant sources.

…………………………………………………………………….…

…………………………………………………………………….…

2.The sugars, starches and cellulose are carbohydrates.

………………………………………………………………………..

………………………………………………………………………

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