Text 4a Polysaccharides

There are a number of starches, which are polysaccharides. They are composed of large numbers of glucose units linked together, which form straight and branched chains (amylose and amylopectin). They exist in granules of a size and shape characteristic for each plant. In this form they are insoluble in water. And foods such as flour and potatoes are indigestible when eaten raw. When heated or cooked in the presence of water, the starch granules swell and gelatinize. They can be more easily digested.

Glucogen is similar to starch in composition, but is made from glucose only by animals, not by plants. There are small amounts of it in the liver and muscles as an energy reserve.

Cellulose provides the rigid structure of vegetables, fruits and cereals. It is insoluble in water. Cellulose consists of many thousands of glucose units. It cannot be digested by man, but can be used as food by cows, whose digestive, tract has microorganisms able to break it down into glucose.

Pectin is another complex polysaccharide, present in apples and many other fruits and in such roots as turnips. Its property of forming a stiff jelly is important in jam-making. Pectin is completely digested and has little effect on the faeces, yet it is often considered as a part of dietary fibre.

Text 4b Health Aspects of Carbohydrates

Fruits and vegetables form sugars in their leaves with the help of sunlight, and store them as starch. Although all sugars and starches absorbed by the body give similar amounts of energy, they have different physiological effects.

Starch provides the greatest part of man's food energy. Sugars are present in the diet as lactose from milk, and fructose from fruit and honey. But excessive consumption of sugars and sweets is associated with tooth decay, development of obesity, heart disease, and bowel diseases such as appendicitis and bowel cancer. At the same time, if diets are low in fat but it is necessary to maintain energy intakes, it is better to eat starchy foods than those of sugars, protein, alcohol.

Some individuals, especially of non-white races, have a limited ability to digest lactose. Lactose intolerance is not usually found in infants whose diet depends on milk, but it may develop in later life.

Diabetes is the result of eating large amounts of readily absorbed carbohydrates. Although there are no recommendations for the amounts of sugars, starches or dietary fibre to be eaten by men, women or children, it is useful to know the amounts of these constituents in foods. The normal daily consumption of sugar should be 100 grams. The proportion of protein, fats and carbohydrates in me daily ration should be as follows: 14—15 % protein, 30 % fats and 55 % carbohydrates.

Unit 5

Вивчіть подані слова i словосполучення

fat	n жир; a жирний
animal fat	жири тваринного походження
butter	n вершкове масло
include	v включати до складу; містити в собі ; утримувати
margarine	n маргарин
oil	n олія
vegetable oil	олія
mineral oil	мінеральна олія
meat	n м’ясо
nut	n горіх
coconut	кокосовий горіх
seed	n сім’я ; v сіяти
oilseed	n сім’я олійної культури
like	v подобатися; любити ;віддавати перевагу; a подібний, схожий; однаковий; в грам. знач. сполучника наче, неначе, як; грам. знач.прийменника таким чином, так
palatable	a приємний на смак, смачний
asid	a кислота; кислотний ;кислий
satiety	n насичення
value	n оцінка, цінність;v оцінювання

Text 5A Fats and Their Properties

Fats include not only "visible fats" such as butter and margarine, cooking Eats and oils, fat on meat, but also "invisible fats" which are found in milk, nuts, lean meat, and other animal and vegetable foods. They are a better source of energy than carbohydrates, and are the form in which much of the energy reserve of animals and some seeds is stored.

Like carbohydrates, fats consist of carbon, hydrogen and oxygen, though the proportion of oxygen is lower. Chemically, food fats consist mainly of mixtures of triglycerides. Each triglyceride is a combination of three fatty acids with a unit of glycerol (glycerin). The differences between one fat or oil and another are largely the result of the different fatty acids in each of them.

Oils are simply fats. They are liquid at room temperature. Usually it is a result of their higher content of unsaturated fatty acids. But on freezing they become solid.

Fats are solid at low temperatures and become liquid when they are heated. Fat makes our meals palatable. Foods rich in fat have a high satiety value, because it is digested comparatively slow. Oils and fats do not dissolve in water.

Animal fats contain vitamins A and D, and varying amounts of cholesterol. Vegetable fats contain carotene (which is converted into vitamin A in the body) and vitamin E, but they have no cholesterol.

Mineral oils (such as liquid paraffin) are chemically different from food fats and oils, though they look similar. They are no1 utilized by the body, but can reduce the absorption of some nutrients.

Unit 6

Вивчіть подані слова i словосполучення:

acid	n кислота;
fatty acid	жирна кислота;
palmitic acid	пальмітинова кислота;
stearic acid	стеаринова кислота;
butyric acid	масляна кислота
oleic acid	олеїнова кислота
linolenic acid	ліноленова кислота
arachidonic acid	кислота арахідонова
bond	n сполука, зв'язок
double bond	подвійна сполука
saturated	а насичений
supersaturated	пeрeнасичений
unsaturated	ненасичений
polyunsaturated	полі ненасичений
affect	v впливати
rancid	а згірклий, протухлий
property	п властивість, якість
treatment	n ставлення; поводження;
̴ with smth	обробка чим-небудь
harden	v тверднути, ставати твердим
lard	n лярд, смалець
contribution	n внесок; сприяння
taste	n смак, присмак; v мати смак (присмак)
release	v звільняти

Text 6A Fatty Acids

There are many different .fatty acids in nature. They differ in the number of carbon atoms and "double bonds" which they contain.

Saturated fatty acids have no double bonds and this makes them stable. Polyunsaturated fatty acids have two or more double bonds which react with the air and make the fat rancid. Large amounts of polyunsaturated fatty acids affect the physical and chemical properties of the fats and make them liquid at room temperature.

Unsaturated fatty acids can be changed into saturated by control treatment with hydrogen. This happens when liquid oils are hardened in the manufacture of margarine.

The most important saturated fatty acids in foods are: palmitic acid and stearic acid. They are major constituents of hard fats such as lard and cocoa butter. Butyric acid is present only in small amounts of milk fat and butter, but it makes an important contribution to their taste. Free butyric acid is released when these fats become rancid.

As for unsaturated fatty acids, the most important of them is oleic acid (monosaturated, with one double chain), which is found in all fats. In olive oil it provides 70 per cent of the total fatty acid content. Linoleic acid (with two double bonds) is found in large amounts in vegetable seed oils such as maize (corn), soya-bean. In small amounts it is found in some animal fats such as pork, Linolenic acid (with three double bonds) occurs in vegetable oils. Arachjdonic acid (with four double bonds) is found in very smart amo­unts in some animal fats. It can be formed in the body from linoleic acid.

Linoleic, linolenic and arachidonic are called "essential fatty acids" because they are required in small amounts for normal health, but cannot be made in the body.

Unit 7

Вивчіть подані слова i словосполучення

sunflower	n соняшник
soya-bean	n соя
manufacture	n виробництво
deposit	n депозит; запас
herring	n оселедець
salmon	n лосось
sardine	а сардина
cod	n тріска
haddock	n пікша