Coagulation of protein: fill in the missing words

Transcription

1 Activity: Coagulation of protein 4a Proteins Coagulation of protein: fill in the missing words Denatured protein molecules are and take up more Chapter 4: Functional and chemical properties of food than they used to. Because of this, they other denatured and start to join together in this is called. As they coagulate, the protein molecules from the food in pockets between them. As coagulation continues, the of the. In the picture below, the egg white has changed from to white and the whole egg has changed from a to a. Egg white proteins begin to coagulate at C, the egg yolk coagulates at C. Due to their ability to coagulate, the proteins in eggs are used in some recipes to together other ingredients, for example, vegetables in a quiche flan, a breadcrumb or batter coating on the outside of some fried fish, the ingredients of a fish cake or beef burger. If a food containing protein is, the coagulated protein molecules and squeeze out the water they were holding. This is called and is why overcooked meat or fish is egg becomes., and why overcooked scrambled

2 Activity: Denatured protein 4b Proteins Denatured protein: fill in the missing words The images below show how the protein molecules unfold and change shape when denatured. Chapter 4: Functional and chemical properties of food Fill in the missing words in the paragraph below to explain the process. Protein molecules can easily be. This means that the that hold the together can be broken, which makes the protein molecule bundle and change. Denaturation of protein molecules can be caused by:, for example, an egg, for example, when adding to cream, making or meat in lime, tomato or lemon juice, for example, in a whisked sponge mixture, for example, when egg whites for meringue, for example, adding.

3 Activity: Proteins anagrams 4c Proteins Solve these anagrams to reveal the key terms for proteins. pointer Chapter 4: Functional and chemical properties of food clue mole mechanic bold a mini coda coaling auto untrained oat

4 Activity: Proteins key word quiz 4d Proteins Key words quiz: Match the word and the definition. Key word Definition Chapter 4: Functional and chemical properties of food Coagulation Denaturation Chemical bonds Amino acids Gluten Protein molecule the chemical bonds have broken and the protein molecule has unfolded and changed shape individual building block for protein molecules a protein that is formed from two separate proteins called glutenin and gliadin when liquid is added to flour to make a dough the joining together of lots of denatured protein molecules, which changes the appearance and texture of the food bonds that hold large protein molecules together in compact, folded bundles Chemical bonds

5 Activity: Protein coagulation explain the process 4e Proteins Protein coagulation Explain the process of coagulation in the box below, using eggs as an example. Explain how and why the process happens and what happens to cooked dishes that contain eggs. Chapter 4: Functional and chemical properties of food

6 Activity: Proteins 4f Proteins Research some dishes that could be made to demonstrate each of the following processes. Process Dishes that could be made Chapter 4: Functional and chemical properties of food Coagulation Gluten formation Denaturation Choose one dish for each process and explain the scientific principles that take place during the preparation and cooking of these dishes. Process Dish chosen Explanation Coagulation Gluten formation Denaturation

7 Activity: Caramelisation and dextrinisation 4g Carbohydrates Chapter 4: Functional and chemical properties of food Comparison alley Compare/contrast the processes of caramelisation and dextrinisation COMPARE To identify and justify similarities and differences between two or more sources of information below, write a summary paragraph outlining why similarities exist and how the working characteristics of starch and sugar affect different dishes. Title: Caramelisation Comparison Alley Similarities Differences Title: dextrinisation

8 Activity: Gelatinisation 4h Carbohydrates The statements below show the steps that occur during the process of gelatinisation. Study them carefully and put them in the correct order in which they happen, (1 to 8). a e Chapter 4: Functional and chemical properties of food When starch granules are put into water and then heated, at about 60 C they start to absorb the water, which causes them to swell up and get bigger. This makes the sauce start to thicken, because there is less room for the swollen granules to move around. b At about 80 C, the starch granules are so swollen that they start to burst and release starch molecules into the surrounding liquid. It is important to stir the sauce regularly as it is heating up, to prevent the starch granules from staying at the bottom of the liquid, where they would swell up, stick together and cause the sauce to have a lumpy texture. f These released starch molecules form a three-dimensional (3D) network that traps water molecules and stops them moving around so much. At this point, around 100 C, the sauce completely thickens and is ready to pour out and serve. This whole process is known as gelatinisation. c g As the cooked sauce cools down, the starch molecules start to form longer chains and the water molecules stay trapped inside them, so the sauce gradually becomes a solid gel. d Starch molecules are made of thousands of glucose molecules joined together, either in long straight chains or short chains with branches. h The starch is stored in plants in tiny packets called starch granules. The size and shape of the starch granules varies in different plants. When starch granules are in put into cold water, they sink to the bottom of the pan.

9 Activity: Carbohydrates quiz 4i Carbohydrates Chapter 4: Functional and chemical properties of food This term means the swelling of starch granules when they are cooked with a liquid to the point where they burst and release starch. 2 This is a savoury food which naturally contains sugar and caramelises when cooked. 3 This method of cooking uses dry heat that is needed for dextrinisation to occur. 4 The temperature at which starch granules are so swollen they start to burst and release starch molecules into the surrounding liquid. 5 This term means the breaking up of sucrose molecules when heated, which changes the texture, flavour and colour. 6 This term means the breaking up of starch molecules into smaller glucose molecules when exposed to dry heat. 7 The temperature at which a sauce completely thickens. 8 This disaccharide makes caramel. 9 Gelatinisation occurs when starchy foods such as are cooked. 10 This dish is made using the caramelisation process. dextrinisation, onions, 100 C, pasta, grilling, crème caramel, gelatinisation, 80 C, sugar, caramelisation

10 1 Activity: The functional properties of fats 4j Fats and oils Fill in the missing words in the paragraphs below. Shortening Chapter 4: Functional and chemical properties of food Shortcrust pastry, and rely on fat to give them their characteristic texture. The coats the flour particles and prevents them from absorbing. This reduces the formation of development, which would cause the dough to become. Fats such as pure vegetable fats are suitable for shortening because of their water content. There are distinctive colours associated with the type of fat used, for example, butter produces a colour. gluten, crumbly, low, biscuits, water, golden, fat, elastic, shortbread Plasticity Fat can be on bread and crackers due to the plasticity of the fat. Plasticity means its ability to be and spread with light pressure. The plasticity of fats is due to their structure. All fats are a mixture of triglycerides, containing different fatty acids. The triglycerides all have different temperatures. This is why fat will soften and melt over a range of temperatures, for example, butter is very hard and so difficult to spread. When chilled the butter has little plasticity. At temperature, the butter and becomes more plastic and which means it can spread easily. fats, such as butter, ghee and solid coconut oil tend to be more at room temperature and so have plasticity. The more unsaturated fatty acids a fat contains the less solid it is and the plasticity it has. Some vegetable fat spreads are made using triglycerides with a low melting temperature, which means we can spread them as soon as they come out of the. A recipe that demonstrates plasticity is, made with butter and plain chocolate. more, chilled, spread, chocolate mousse, saturated, shaped, softens, chemical, refrigerator, melting, solid, room, less

11 2 Activity: The functional properties of fats 4j Fats and oils Aeration Fats such as and vegetable spreads are able to trap Chapter 4: Functional and chemical properties of food bubbles when they are beaten together with sugar when making a mixture. These fats can do this because they have. Cooking do not trap air as effectively as fats that have plasticity. When fat and sugar are together, air bubbles are trapped in the mixture. The mixture becomes in colour and the volume. The ability of fats to a mixture in this way is very important for producing a light, spongy texture in a baked cake. oils, aerate, butter, lighter, air, increases, plasticity, cake, creamed Emulsification Oil and water do not mix, but if they are forced together by thorough mixing, they stay in a suspension for a very time. If left, they will separate out, with the floating on top of the water. To stop the mixture separating out again, an must be added. One example of an emulsifier is egg yolk, as it contains. This acts as an emulsifier when added to a mixture such as. of water and the amount of oil. are either oil-in-water or water-in-oil, depending on the amount Examples of emulsions include milk, cream, Hollandaise sauce. Examples of water-in-oil emulsions include, vegetable fat spreads and. emulsions, oil, salad dressings, lecithin, naturally, butter, short, oil-in-water, emulsifier, mayonnaise

12 Activity: Emulsification 4k Fats and oils Chapter 4: Functional and chemical properties of food Work in a group of four, but split into pairs. One pair should complete task A and the other should complete task B. Discuss and describe your thought processes throughout. In pairs, read the information and study the diagrams below. Then change the written information and diagram to the format described in your task (A or B) a flow diagram or a storyboard. Making butter Butter is made from milk. It contains a natural emulsifier called lecithin; an emulsifying agent keeps the food from splitting it keeps it stable. Emulsions in food Tiny fat droplets in milk are suspended in a white liquid that is made up of protein, water, carbohydrate, minerals and vitamins. When the milk is left to stand in a cool tank, the fat droplets rise to the top to form a layer of cream. The cream is skimmed (taken) off the milk. This leaves skimmed or semi-skimmed milk behind, depending on how much cream is skimmed off. The cream is churned, which means it is continuously stirred until the droplets of fat start to stick together. Gradually, as more and more of the fat droplets stick together, the cream thickens and then turns into butter. Most of the liquid which is called buttermilk is drained away. The small amount of liquid that is left forms tiny droplets within the fat. A natural emulsifier in the milk keeps these droplets suspended in the fat. From milk to butter Oil-in-water emulsion Milk Water-in-oil emulsion Butter Water Oil Task A: Create a flow diagram to demonstrate the process. Flow diagram Task B: Create an animation or storyboard for a film clip to explain what happens during the process. Storyboard After completing the task Each pair gives feedback to the other. Each pair learns from the other through the explanation of the processes. Each student should then answer questions about how butter is made.

13 Activity: Pastry making investigation 4l Fats and oils Chapter 4: Functional and chemical properties of food These pastry samples were made as part of an investigation to find the most suitable fats to make shortcrust pastry. The samples were made using strict controls to ensure the results are reliable. Shortcrust pastry recipe 50g flour 25g fat Pinch salt 10ml cold water Results Sample Flour Fat Result Control 50g plain flour 12½g block fat and 12½g lard The pastry had a short and crumbly texture and melted in your mouth. XYX 50g plain flour 25g lard The pastry was very crumbly and greasy. It was very fragile and pale in colour. The pastry was bland. XYY 50g plain flour 25g butter The pastry was crumbly and had a rich flavour. YXX 50g plain flour 25g block margarine The pastry was crumbly and a good flavour. YYX 50g plain flour 25g oil The pastry was bland and not crumbly. YXY 50g plain flour 25g low fat spread The pastry had a flaky texture and layers were created. Air bubbles could be seen in the pastry. Analysis 1 Using your knowledge of the functional and chemical properties of fats, conclude the experiment by explaining which fats are suitable for making pastry. Give reasons for your answer. 2 Explain the controls that the students would have followed to make this an accurate and fair test. 3 Which of the samples could not be tasted by a vegetarian? Explain your answer. 4 If you have made pastry, give five rules or tips for making good quality pastry.

14 Activity: Raising agents 1 4m Raising agents Look at the foods below. Match the food product with the raising agents that were used to make them rise. Don t forget there may be more than one agent used during the cooking process. Raising agents: air, steam, baking powder, yeast, bicarbonate of soda Chapter 4: Functional and chemical properties of food Mixture Which raising agent(s)? Mixture Which raising agent(s)? Chocolate éclairs Puff pastry Whisked sponge cake, for example, Swiss roll Scones Gingerbread Fruit buns Creamed sponge cake, e.g. Victoria sandwich cake Croissants Batter, for example, Yorkshire puddings All-in-one chocolate muffins Bread rolls Profiteroles

15 Activity: Raising agents 2 4n Raising agents For each of these items, identify the agent(s) that made the food rise and fully explain the process involved. Food Raising agent Explanation Chapter 4: Functional and chemical properties of food Profiteroles Swiss roll Bread rolls Croissants Sponge cake Gingerbread

16 Activity: Raising agents yeast 4o Raising agents The following test was carried out to find the best conditions for yeast to release carbon dioxide. Test tube Contents Results Chapter 4: Functional and chemical properties of food Test tube A Yellow balloon Test tube B Orange balloon Test tube C Blue balloon Test tube G Green balloon Yeast, warm water (30 C), sugar, left for 60 minutes Yeast, cold water, sugar, left in the refrigerator for 60 minutes Yeast, warm water (30 C), salt, left for 60 minutes Yeast, hot water (80 C), sugar, left for 60 minutes The balloon inflated Signs that some inflation was starting to take place Deflated balloon Deflated balloon Key words Fermentation Carbon dioxide Food Moisture Time Temperature Analysis: 1 Using the results of the investigation and your knowledge of the functional and chemical properties of yeast conclude the experiment by explaining: each result the ideal conditions for yeast when making bread. Give detailed reasons. 2 Explain the controls that the student would have followed to make this an accurate and fair test.

17 Activity: Raising agents 4p Raising agents This text is about raising agents. Fill in the missing words. Gases when they are heated and are capable of raising a mixture. Raising agents are used to introduce a into a Chapter 4: Functional and chemical properties of food mixture. The used for this purpose are: (CO 2 ), (a mixture of gases) and (water in a gaseous state). As the batter or dough cooks, the become set in the mixture, giving breads, cakes, scones and other baked goods a soft, sponge-like texture. Baking powder is used as a raising agent for a range of doughs and batters. It is made from a combination of alkaline and acid substances (usually and ) that react when they come into contact with moisture and warmth to produce gas bubbles. Self-raising flour is plain flour with added to it. In bread production, converts and into gas, which causes the dough to, and, which evaporates during baking. The whole process is called. It will only take place when certain conditions are available. These conditions are:,, and. is a mixture of gases and it can be incorporated into mixtures in a number of ways to help them rise, such as flour, fat and sugar together, eggs, and to make pastry and fat into flour. When water is boiled, water molecules turn into. This causes mixtures such as, and pastry to rise. The oven temperature must be in order to raise the liquid rapidly to boiling point. Choose from these words. air carbon dioxide folding puff steam air carbon dioxide food rise sugar alcohol choux gas rolling time baking powder cream of tartar gas bubbles rubbing in warmth batters creaming gases sieving whisking bicarbonate of soda expand hot starch yeast carbon dioxide fermentation moisture steam Yorkshire pudding