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Lesson 5 meat as a source of protein






1.Read and memorize the following words:

requirement [rı 'kwaı ə mə nt] вимога

e.g. At present milk and its products are daily requirements for the population in most parts of the world.

to investigate [ı n'vestı geı t] досліджувати

e.g. The nutritionist investigated the properties and nutritional value of frozen meat.

to estimate ['estı meı t] оцінювати

e.g. It is very wise to estimate the whole diet before making any changes.

measure ['meʒ ə ] міра, одиниця вимірювання

e.g. Calorie is a measure of energy we get from food.

to ingest [ı n'ʤ est] ковтати, проковтувати

e.g. Saliva (слина) moistens the food and helps it to be ingested.

adequate ['æ dı kwə t] достатній

e.g. An adequate intake of all the nutrients is essential for health and activity.

to supply [sə 'plaı ] постачати

e.g. Vegetables supply great quantities of nutrients and are also an important source of dietary fibre.

a surplus ['sɜ: plə s] надлишок

e.g. Brazil had a surplus of coffee last year.

moisture ['mɔ ı sʧ ə ] волога

e.g. Less tender cuts of meat are cooked in the presence of moisture (in water or in moist atmosphere).

starch [stɑ: ʧ ] крохмаль

e.g. There are three major groups of carbohydrates in food: sugars, starches, cellulose and related materials.

to coagulate [ˌ kə ʊ 'æ gjʊ leı t] коагулювати, зсідатися

e.g. During cooking the flour and egg proteins coagulate.

2.Match the words with their definitions.

1. to coagulate 2. to estimate 3. to supply 4. to investigate 5. starch 6. measure 7. requirement 8. adequate 9. moisture 10. to ingest a) something needed or demanded b) make a careful study of c) to calculate (value, cost, etc.) d) something with which to test size, quantity, etc. e) to move food or drink down the throat from the mouth f) enough for the purpose g) to give or provide something needed h) liquid in the form of steam or mist i) to change to a thick and solid state j) white, tasteless food substance (as in potatoes, grain, etc.)

 

3.Read and translate the text.

Human protein requirements. Human requirements for protein have been thoroughly investigated over the recent years and are currently estimated to be 55 g per day for adult man and 45 g for woman. (There is a higher requirement in various disease states and conditions of stress).

Protein quality. The quality of protein is a measure of its ability to satisfy human requirements for the amino acids – those that must be ingested ready-made, i.e. are essential in the diet, and those that can be synthesised in the body in adequate amounts from the essential amino acids. There is a popular impression that the qualities of proteins from animal sources are greatly superior to those from plant sources. This is true only to the extent that many animal sources have Net Protein Utilisation, NPU, (a measure of the usefulness of the protein to the body) around 0.75 while that of many, but not all plant foods is 0.5-0.6. The value of meat in this respect is that it is a relatively concentrated source of protein, of high quality (0.75-0.8), highly digestible, about 0.95 compared with 0.8-0.9 for many plant foods, and it supplies a relative surplus of one essential amino acid, lysine which is in relatively short supply in most cereals.

Effect of cooking on protein quality. At a temperature below 100°C when proteins are coagulated, there is no change in nutritional quality. The first changes take place when food is heated to temperatures around 100°C in the presence of moisture and reducing sugars, present naturally or added to the food. At a higher temperature or with more prolonged heating, the lysine in the food protein can react with other chemical groupings within the protein itself and more becomes unavailable. In addition the sulphur amino acids are rendered partly unavailable. At the temperature needed to cook meat there is little loss of available lysine or the sulphur amino acids but there can be some loss if the meat is heated together with reducing substances, as may be present when meat is canned with the addition of starch-containing gravy or other ingredients.

4.Answer the following questions.

1.What are human requirements for protein per day?

2.Are qualities of proteins from animal sources similar to those from plant sources?

3.What is Net Protein Utilisation?

4.What is protein quality of meat?

5.What is the effect of cooking on protein quality?

5.Match the two parts of the sentences to make true sentences.

1.Human requirements for protein are … 2.Under the quality of protein we mean … 3.The qualities of proteins from animal sources are … 4.Meat supplies … 5.At a temperature below 100°C … 6.The first changes take place when… … superior to those from plant sources. … there is no change in nutritional quality. … 55 g per day for adult man and 45 g for woman. … food is heated to temperatures around 100°C in the presence of moisture. … a relative surplus of lysine. … its ability to satisfy human requirements for the amino acids

 

6.What parts of speech are the following words? Translate them into Ukrainian. Make up your own sentences with each of them.

Supply, supplied, supplying, supplement; moist, moisture, moistly, moistness.

7.Read some more information about proteins and say what the word ‘protein’ means.

Proteins represent the stream of life. They make up the vital part of that essential jelly material of the living cell – the protoplasm. The beginning of life at this and perhaps at few other planets must have been associated with the formation of proteins. This word means “to make first place”, for there is no life without proteins. If you would like to see proteins, look over your own body, or you can look at one that is practically pure, that is the white of an egg which is almost all protein or albumen and water. Usually these most essential of life’s materials have the indefinite and glue-like form known as a colloid though some of them have been separated as pure and definite crystals.

8.Prove that meat is one of the best sources of protein for human diet.






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