Задания

1. Ответьте на вопросы:

1. What is the composition of proteins? 2. What foods are valuable sources of proteins? 3. What is the basis of protein classification?

2. Найдите в тексте синонимы выделенных слов.

the significance of nitrogen is indicated by the fact; the nitrogen content usually ranges from 10 to 18 per cent; meat, milk ... are rich in proteins; proteins are complicated in character; they are made up of very many amino acids tied together; variation in the quality of proteins has ended in their grouping; if it is a single protein in the nutrition; a complete protein is one that is sufficient to maintain life; rich sources of proteins are cereals, fish, meat ...

3. Укажите номера пропущенных слов.

1. Cereals rich in protein are essential for the ... of a human being. 2. It is necessary to include into the human diet foods that ... proteins. 3. There are three kinds of proteins that are ... for a body. 4. One of the best ... of vitamins are fruit and vegetables. 5. It is essential for people to consume various foods of great ... . 6. This substance is more ... in nature than that one. 7. 0ne must remember that proteins are of both plant and animal ... . 8. The classification of proteins is based upon their ability ... normal growth and to ... life. 9. It is possible to say that the importance of food ... in proteins for the human diet cannot be overestimated. 10. Proteins ... in the kind and number of amino acids present.

1. complex, 2. nutritive value, 3. vary, 4. origin, 5. high, 6. nutrition, 7. to support, maintain 8. contain, 9. essential, 10. sources

4. Переведите данные предложения на русский язык, выделив подлежащее.

1. It is known that proteins contain different chemical elements. 2. It is evident that proteins are complex in nature. 3. It is said that cereals and cereal products are valuable sources of proteins. 4. 0ne should know that proteins classification is based on their variation in quality. 5. One can find protein in many different foods. 6. Maintaining life partially complete proteins do not support normal growth. 7. Maintaining life is the most significant function of proteins. 8. To include a new product into the baby diet one should be aware of its high food value. 9. To include a new product into the baby diet requires the awareness of its high nutritive value. 10. That proteins are complex in nature is proved by their composition. 11. That he has carried out very interesting research in the field of baby nutrition is known to us. 12. That the human diet should be diverse and nutritive is shown by life itself.

«Vegetable proteins»

1. Прочитайте текст и выделите ту часть, где представлена классификация белков.

Plants can build up from nitrates and salts of ammonia complex nitrogenous substances called proteins. A typical protein is eggalbumin, the white of an egg. It is colourless, thick, sticky¹, fluid², soluble in water. When put into boiling water, it coagulates, i.e., it becomes a solid mass and is no longer soluble in water. If the white of an egg be exposed to the air, it decomposes into a great number of substances. If heated with dilute acid, it breaks down into ammonia carbon dioxide, and a number of complex substances. Proteins are built up principally from the five elements: carbon, hydrogen, oxygen, nitrogen and sulphur.

The proteins found in the vegetable kingdom can be divided into seven main classes. We shall consider here only the glutenins, the prolamins and the globulins. The glutenins to which class wheat glutenin belongs are proteins which are not soluble in neutral salt solutions or in alcohol.

The prolamins are proteins soluble in alcohol. They were once called gliadins. To this class belongs gliadin from wheat or rye, hordein from barley, and zein from maize. The globulins are proteins insoluble in water but soluble in solutions of common salt. They are almost all coagulated by heating their solutions. It has long been known that, if a ball of dough (made from flour and water) be washed out, a compact mass of rubber-like material is left. This is gluten³. On treating with alcohol, it can be separated into two substances – glutenin and gliadin.

1. sticky – вязкий

2. fluid – текучий

3. gluten - клейковина