Eggs by Jenny Ridgwell
Eggs Contents What is a buffet? Functions of ingredients in food products Ingredients used in cooking Special dietary needs Properties and functions of ingredients Eggs Properties and functions of eggs Function of nutrients Food hygiene Quality foods Food production systems What is HACCP Safety and Quality Checks Designing new food products CAM in food production Quality Checking - what went wrong Glossary of terms Crossword. ISBN-13 978-1-901151-12-1 The pages of this book may be photocopied by purchasing schools and colleges only for use in classrooms with students. The pages may not be photocopied by others without prior permission from the publisher. No part of this book may be reproduced, stored in a retrieval system or transmitted in any other form or by any other means without prior permission from the publisher.
Research Eggs Design theme Buffet products In preparation for the examination you should research: different uses of eggs in buffet products the properties and functions of ingredients used in buffet products production systems used to produce quality food products. This book has been compiled from previous work by Jenny Ridgwell and Ridgwell Press. Most of this work has appeared in other Ridgwell Press publications, but has been chosen to focus on the brief. There is no guarantee that any of the work reflects the examination questions, so students and teachers must make their own provision for questions that may be asked. 5
What is a buffet? A buffet is a spread of ready to eat food which is served at parties, weddings, meetings and any other gathering where there are lots of people to feed. People do not sit down to eat buffet food, they help themselves, so they do not need knives to cut up the food, but they might use forks. How to choose food for a buffet? Food should be easy to eat Dishes should be served in small portions which can be hand held Food is prepared in advance Food should look attractive and not dry out or change colour when it is served There should be a range of savoury and sweet choices The choices should cater for different needs such as vegetarians, gluten free, lower calorie and healthy eating. Foods should appeal to the group which could include children. Food must be safe to eat, especially when serving so many people. This means careful temperature control. Chilled food should be kept at temperatures below 8 C and not kept out at room temperature for more than 2 hours. Food choices for a buffet Why is this a good buffet food? Things to think about Scotch egg, Tasty and easy to eat. Needs careful temperature control. Quiche or egg custard tart Vol au vents Croquettes Choux buns Lemon meringue Pancakes Can be cut into slices to make it easy to handle. Can have a variety of flavours. Easy to handle and can have a range of fillings. Tasty and can have a range of flavours. Easy to eat and can be sweet and savoury. Nice flavour and looks attractive. Served hot and can be savoury or sweet. Needs careful temperature control. Needs careful temperature control. Often served hot so needs care. Must be eaten fresh. May be messy to serve and difficult to make. How will they be made in advance? Victoria sponge Popular and easy to eat. Rather traditional. Mayonnaise Mixes with salad and fillings. Needs careful temperature control. What about healthy choices? Customers are very keen to have healthier food choices, so the menu should include products with High fibre content Lower salt Good balance of nutrients Lower fat content Lower the salt for healthy choices.
What is a buffet? Catering for large numbers How can these dishes be made on the large scale to save time and money? Scotch eggs Quiche Vol au vents Croquettes Choux buns Lemon meringue Pancakes Victoria sponge Mayonnaise Ready made components to save time Buy hard boiled eggs. Buy ready made pastry and liquid egg. Buy ready made pastry and sauces. Buy instant potato and sauces. Buy ready mix choux pastry. Buy ready made pastry, liquid egg, lemon juice. Buy pancake mix. Buy cake mix and filling. Buy ready made. Safety when handling buffet food Always wash your hands before and after handling food. Keep your kitchen, dishes, and utensils clean. Don t cross-contaminate. Keep raw meat and poultry apart from cooked foods. Keep food hot in the oven or cold in the refrigerator until serving time. This means foods will be held at safe temperatures for a longer time. Food should not be at room temperature for more than two hours. Keep track of how long the foods have been on the buffet table and discard anything after two hours. Leftovers from the buffet should be thrown away if any food has been left for two hours or more on the buffet table. IF IN DOUBT THROW IT OUT. Checking the temperature Use a food probe to test the inside core temperature of cooked food. Questions 1. What are the advantages and disadvantages of using the following ready made components when cooking food on a large scale: a) ready made pastry (2 marks) b) cake mix (2 marks) c) a pot of mayonnaise (2 marks)? 2. List 5 things to think about when choosing food for a buffet. (5 marks) 3. List 3 important safety issues when serving buffet food. (3 marks) 4. Explain how you would a) lower the fat content of a quiche, b) lower the salt in a scotch egg, c) increase the fibre in a quiche recipe. (2 marks for each answer) 7
Functions of food ingredients The ingredients in food products have different functions depending upon how they are used. Below are some examples of food products and the functions of the main ingredients. moisturising and enriching margarine or butter Flapjack bulking oats sugar adding texture oats shortening margarine or butter flavouring syrup binding syrup flavouring cherries Cherry scones moisturising and enriching margarine or butter adding texture sugar-glaze colour cherries aerating baking powder binding milk shortening margarine or butter bulking flour sugar binding eggs Sponge cake moisturising and enriching margarine or butter flavouring vanilla essence bulking flour sugar aerating SR flour shortening margarine or butter 8
Functions of food ingredients The ingredients in food products have different functions depending upon how they are used. Below are some examples of food products and the functions of the main ingredients. flavouring strawberries Strawberry dessert moisturising and enriching cream adding texture strawberries setting gelatine colour strawberries bulking sugar thickening gelatine Bread moisturising and enriching margarine or butter aerating yeast steam binding water bulking flour Chocolate chip biscuit shortening margarine or butter moisturising and enriching margarine or butter flavouring chocolate adding texture chocolate chips colour chocolate bulking flour and sugar 9
Functions of ingredients in food products Ingredients have different functions in food products. The diagrams below show some of the ingredients and the functions of those ingredients in food products. Flour adds flavour nutritious food helps form the structure acts as bulking ingredient thickens liquids enriches mixtures Fat increases shelf life adds moistness adds flavour shortens baked mixtures holds air introduces gases into mixtures Raising agents helps to give lightness to baked products makes the baked product a better eat 10
Functions of ingredients in food products Ingredients have different functions in food products. The diagrams below show some of the ingredients and the functions of those ingredients in food products. Sugar makes a more tender baked product adds texture preservative sweetening helps keep moisture in baked goods adds bulk colour - browning in baking nutritious food thickens sauces helps form the framework enriches mixtures traps air acts as an emulsifier binds dry ingredients glaze for pastry Liquid helps gelatinisation of starch helps action of raising agent helps formation of gluten binds dry ingredients 11
Ingredients used in cooking Flour Choosing a flour White flour is traditionally used for pastry and cakes with a raising agent sometimes added to help the mixture rise. Flour with added raising agent is called Self raising flour. If you choose wholemeal or brown flour you need to add more water to the dough and the baked product may have a drier texture. However, wholemeal flour contains more dietary fibre than white flour so is useful if you want to increase the dietary fibre in your diet. Gelatinisation of starch When starch and water are heated, the water penetrates through the granules causing them to swell and burst. The mixture thickens by a process called gelatinisation. This process happens when flour is used to make thickened sauces like custard, and in bread, cakes and scones. Self raising flour Self raising flour is used for cakes since it contains a raising agent which helps mixtures to rise. To convert plain flour into self raising flour, add 1 level teaspoon of baking powder to 100 grams of flour. Sift the baking powder into the flour and blend thoroughly. Raising agents Raising agents are added to cakes and breads to make them rise. Raising agents are gases which expand on heating to push up the surrounding mixture. Raising agents include: air (used in meringues and flaky pastry) steam (used for batters and choux pastry) carbon dioxide (from yeast and baking powder) Types of raising agent used in baked goods: baking powder sodium bicarbonate raising agents in self raising flour yeast steam from water Raising agents such as baking powder give baked goods a lighter texture. Raising agents, such as baking powder and sodium bicarbonate, give off carbon dioxide gas when cake mixtures and scones are cooked. Baking powder Baking powders usually contain sodium bicarbonate and an acid. Questions 1. What is meant by the term gelatinisation? 2. What flour would you choose for sponge cake and choux pastry, and why? 3. Suggest two food products which could be made from each of the flours listed below: a) white wheat flour, b) strong white flour, c) brown flour, d) wholewheat flour, e) stoneground flour, f) self raising flour. 4. List the different types of raising agent used in cooking and give examples of their use. 12
Ingredients used in cooking Fats in baking In baking, fat acts as a shortening agent and helps to make the products crumbly, short and moist. If you did not use fat in a mixture the result would be hard and dry. If you increase the fat content the product becomes more crumbly and short. Fat in the form of butter or margarine is used in pastry to help improve the flavour and texture of the baked product.the shelf life of pastry, cakes and biscuits is increased when fat is added. Fats used in large scale manufacture often contain emulsifying agents which help limit the development of gluten and make a shorter, lighter crumb. Fats can be liquid, flake, hydrogenated, emulsified, block, or plasticised - all of these products help to change the texture during manufacture. In large scale production, if butter is used, less volume is produced in the finished product. Vegetarian margarine Most of the margarines used in cake and biscuit manufacture are suitable for vegetarians. In other words, they are not made from fat from animals such as fish oils. Vegetarian margarines are made from seeds such as sunflower, rape and corn. Reduced or low fat spreads These spreads contain 40-80% fat compared to butter and margarine which contain 80% fat. The reduced fat spreads have a higher water content which makes them unsuitable for frying, roasting and baking. They are used for spreading on bread. Fats in cooking Fat has the following uses in cooking: enriches mixtures holds air adds moistness increases shelf life adds flavour acts as a shortening agent Fats used in cooking margarine made from a range of processed animal and vegetable fats and used for baking cakes and biscuits butter made from churning cream and used in baking for flavour lard made from pig s fat and used for pastry and frying suet made from the fat around animal s kidneys and used for suet pastry oil usually made from seeds such as sunflower, corn and olives and used for frying, baking and roasting ghee clarified, unsalted butter used in Asian cooking Questions 1. What sort of fat would you choose for a) sponge cake, b) frying pancakes? Give your reasons. 2. Give 2 functions of fat in baked products. 3. Which fats could not be used in vegetarian products? Give your reasons. 4. Which fats are not suitable for baking? 13
Ingredients used in cooking Eggs Eggs have many uses in cooking. On heating, eggs coagulate and set - for example in quiches. Egg proteins stretch when beaten and hold air - for example in making meringues. Egg yolks contain fat which enriches mixtures. Lecithin in egg yolks acts as an emulsifier to stabilise cake and biscuit mixtures and thicken mayonnaise. Eggs can be used to coat foods such as fried fish and scotch eggs. Beaten egg is brushed on top of pastries and acts as a glaze which turns golden on baking. Eggs are nutritious and provide protein, vitamins and minerals. Eggs bind dry ingredients together such as beefburgers and croquettes When egg yolk and milk are heated gently, the mixture thickens. Salmonella in eggs Salmonella is the name of a food poisoning bacteria which can be found in eggs. The Government has warned that we should not eat raw eggs. Care must be taken when handling eggs during cooking as the shells may also contain salmonella. Other foods could be cross contaminated with salmonella during food preparation. When cooking with eggs, make sure that the product is thoroughly baked so that the salmonella bacteria are killed. In large scale food preparation, pasteurised eggs are often used, since they have been heat treated to kill salmonella and so avoid the risk of food poisoning. binding ingredients together (cakes) hold air when beaten (meringue and cakes) glaze foods (pastries) thicken liquids (quiche) emulsify ingredients (mayonnaise) Questions 1. Make a list of ten food products which use eggs as an ingredient. For each product, state the function (use) of the egg in the recipe. 2. Eggs are known to contain salmonella bacteria. When baking cakes, how would you make sure the baked product contained no salmonella bacteria? 14
Functions of ingredients in food products Shortening ingredients Fat improves the flavour and keeping quality of baked products. The more fat used, the more crumbly the baked product will be. Shortening ingredients such as fat and oil help to make mixtures such as cakes and pastries light and crumbly. Fat is absorbed by flour and the starch gelatinises and this inhibits the formation of gluten which would toughen the mixture. If fat is not used with a flour and water mixture, the mixture is hard and tough - in other words, not short. Butter and margarine are usually chosen for cake recipes for flavour and shortening. Raising agents Raising agents such as baking powder in self raising flour help cakes to rise by producing carbon dioxide gas when mixed with liquid. On heating, this gas expands and pushes up the mixture, making it light. The mixture sets on baking forming the structure. Binding ingredients Ingredients such as water, milk and egg are used to bind dry ingredients such as flour and sugar together in cakes, biscuits and breads. The binding ingredients bind the dry ingredients into a dough which is then baked into a structure. The liquid helps the flour to gelatinise and form gluten and is essential for the raising agents to work. Flavour and texture Baked products can be savoury or sweet and many ingredients can be added to give flavour and texture. Savoury flavours for baked products include cheese, herbs and spices. Sweet flavours include dried fruits, sugars and chocolate. Sugar not only sweetens cakes and enhances the flavour, but also adds bulk and helps to improve the texture. Ingredients can provide a variety of textures - these include nuts and seeds for crunchiness, dried fruits for moistness. Questions 1. How does fat shorten mixtures - what does the term mean? 2. What is meant by the term binding? 3. Give an example of binding ingredients together. 4. Give 2 examples of ingredients used to flavour savoury and sweet foods. 15
Functions of ingredients in food products Use the pages on Functions of ingredients in food products to answer the questions. Make a list of the ingredients in each product then describe the functions. Recipes are found at the end of the book. Food product ingredients Function of ingredients Quiche Pancakes Sponge cake 16
Functions of ingredients in food products Use the pages on Functions of ingredients in food products to answer the questions. Make a list of the ingredients in each product then describe the functions. Recipes are found at the end of the book. Food product ingredients Function of ingredients Lemon meringue pie Mayonnaise Scotch egg 17
Functions of ingredients in food products Standard components are ready made products such as ready made pastry, sauces, ready prepared salads. Food product What standard components can be used? Quiche Pancakes Sponge cake 18
Functions of ingredients in food products Advantages of using standard components Saves time Saves energy Makes a consistent product Can use if staff do not have skills needed Saves buying specialist equipment Saves buying and storing of raw ingredients Food product ingredients What standard components can be used? Lemon meringue pie Mayonnaise Scotch egg 19
Special dietary needs Here are examples of special dietary needs people weight watching - eating fewer calories low fat diets - reducing fat in food eaten people with allergies to some foods vegetarians who do not eat meat or fish low salt. Weight watching People who want to lose weight make sure that the amount of food they eat meets their daily needs. These people watch the calories in the food they eat and may choose foods which are reduced fat sugar free. Low fat diets For our health we should cut down on the amount of fat that we eat. We should replace the saturated fat with unsaturated fat. Ways to cut down on fat change whole milk and use semi skimmed or skimmed milk choose lower fat foods - read the label don t add cream to recipes. Food allergies Allergic reactions are caused by allergens. Peanuts, milk and eggs are common food allergens. If a person thinks they have a food allergy, they should see a doctor and get an allergy test. Food labels show allergens, so that people with food allergies can make safe choices. The range of ingredients in food products that cause common food allergies include peanuts, tree nuts such as almonds and hazelnuts, crustaceans such as prawns, milk, eggs, sesame seeds, soya, celery, fish, gluten and wheat. People with coeliac disease are unable to eat cereals with gluten (wheat, rye, barley, oats), so they must eat a gluten free diet. Anaphylactic shock is a very serious allergic reaction after eating peanuts. Vegetarian symbols Vegetarian A vegetarian eats a diet of grains, pulses, nuts, seeds, vegetables and fruits with or without the use of dairy products and eggs. Lacto-ovo-vegetarian eats dairy products and eggs. Lacto-vegetarian eats dairy products but not eggs. Will not eat lard or suet. Vegans do not eat dairy products, eggs, or any other animal product such as butter, lard, suet. Food ingredients that vegetarians must avoid: Gelatine is made from boiling animal bones and products. It is used in low fat spreads, desserts, and sweets. Suet and lard are animal fats, and some margarines are made with animal fat. Look for the vegetarian symbol on food labels, such as a V. Low salt Look out for foods labelled reduced salt or lower salt foods. Don t add salt to your foods. Look at the food labels and avoid foods which are high in salt. Diabetics should follow a healthy diet. No special food products are needed. Questions How should the following people choose food to meet their dietary needs - give 2 points for each. a) weight watchers, b) people on low fat diets, c) people with food allergies, d) vegetarians, e) people on low salt diets? 20
Properties and functions of ingredients Ingredients have different functions and working properties when making food products. Functions of ingredients Function What happens Examples Adding colour Adding flavour Adding texture Aerating and lightening Binding Bulking Emulsifying A range of colours makes food more attractive to look at. Salt, pepper and herbs, and strong flavoured ingredients improve the flavour of food. Different ingredients provide textures such as soft, crunchy, hard and dry, to make food more appetizing. Add lightness by adding air, carbon dioxide or steam. Some ingredients need sticking together by binding the pieces. Foods can add bulk to make up the main part of a recipe. Ingredients hold oily mixtures together. Add garnish to colour a dish such as slices of tomato on salad. In savoury food add bacon and tomatoes. Chocolate and coffee flavour sweet food. Crunchy celery in a salad, apples in fruit salad. Whisking eggs, adding raising agents, adding milk to batter. Ingredients in beef burgers and veggie burgers need binding and binding dry ingredients to make pastry and pasta. Flour is used in bread and biscuits. Oats bulk muesli. Egg holds together foods such as oil and vinegar in mayonnaise. Glazing This adds colour and shine. Eggs are brushed onto pastry for a golden glaze. Preserving Setting food Shortening Sweetening Thickening Ingredients help food keep longer. Foods such as jellies and custard are set. Fats and oils shorten flour mixtures. Sugar and dried fruits sweeten. Soups and stews need thickening. Sugar, salt and vinegar are used to preserve jam, fish and pickles. Gelatine sets jellies. Cornflour sets sauces, eggs set flans. Pastry is made crisp and crumbly in texture. Sugar, fruits and honey. Flour and starchy vegetables or bread to thicken soups and stews. Questions Give an example of an ingredient that shows each of these functions: 1. adding colour 2. adding flavour 3. adding texture 4. aerating 5. binding 6. bulking 7. emulsifying 8. glazing 9. preserving 10. setting 11. shortening 12. thickening (total 12 marks, 1 for each answer) 21
Eggs How are eggs farmed? 66% laying cages, 27% free range, 7% barn. Organic eggs are free range and the hens live on organic land with an organic diet. Lion quality mark shows that eggs have been produced to the highest standard, and the hens are tested for salmonella and the hygiene is strictly controlled. Use of eggs in cooking Eggs are a very useful cooking ingredient. Without them we couldn t make omelettes, cakes, noodles, icecreams and sauces. Functions and properties of eggs: Function How it works Example Binding Coating Glazing or finishing Thickening and setting Trapping air - aeration Emulsifying Enriching Garnishing Eggs bind and stick dry ingredients together. The egg provides moistness. The egg protein coagulates when heated. The egg coagulates with heat and protects the ingredients during frying. Beaten egg is brushed over savoury pastries before baking. The egg protein coagulates with heat and forms a shiny surface on baked products. The egg is a liquid food which contains protein and this thickens and coagulates with gentle heat. 1 medium egg will set 125ml of milk or cream. Eggs can trap air when they are whisked or beaten. Eggs whites trap air to form a foam. A stabiliser in egg white foam is the protein albumen. This is also known as aerating and lightening. Egg yolk contains an emulsifying agent, called lecithin which holds together oil and water. Egg adds nutritional value and thickens and adds colour. Hard boiled eggs can be sliced and chopped. Beefburgers, fishcakes and croquettes. Dip a fishcake in beaten egg then coat it with flour or breadcrumbs. Coatings are used for croquettes and fried fish. Eggs are used to glaze savoury pastry such as cheese straws, vol au vents and bread dough to make it golden when baked. This improves the finish. Eggs thicken custards, savoury flans, quiches, soups and sauces. Eggs thicken as you make omelette and scrambled egg. This is used for soufflés and cakes such as sponges. Also choux pastry and meringues. Used for mayonnaise to hold together oil and vinegar. Egg is used in sauces, potatoes and pastry. Used on salads and sandwiches. Eggs are sold in different sizes small, medium, large and very large. Large eggs are usually used in cooking. Fact egg white proteins coagulate at 60 C. egg yolk proteins coagulate at 70 C. egg yolk proteins thicken at 65 C. 22
Eggs For large scale food production, liquid pasteurised eggs are often used. These are safe to use as dangerous bacteria have been destroyed by heat in the pasteurisation process. They can also use: frozen egg spray dried pasteurised egg. Allergy Egg allergy is most common in children under twelve months. Few children are allergic to egg after the age of six, though in some cases this allergy can persist to adult life, especially for people with a family history of allergy. Nutrition Eggs are a nutritious foods and good value for money. There is no recommended limit on how many eggs we should eat. Nutrition Easily digestible protein needed for growth. Essential vitamins A,D,E and B groups but no vitamin C. Minerals iron, phosphorus and zinc. Low saturated fat, and only 80-90 kcal an egg. How old is an egg? Use eggs within their date marks which can be found on the egg carton. Some eggs have the use by date stamped on their shells. Questions Give an example of a food product which is made using each of these functions/ properties of eggs:.... 5.. 7. binding coating glazing thickening trapping air emulsifying enriching garnishing 8. (8 marks) 9. Why do food producers sometimes use pasteurised egg in their products? (2 marks) 10. What are the main nutrients found in eggs? (4 marks) 11. Give 3 rules to help handle eggs safely. (3 marks) Food safety Eggs, like any protein rich food, need to be handled carefully. Raw eggs may contain salmonella bacteria which cause food poisoning. Egg handling guidelines: Store eggs at a constant temperature below 20 C Store away from strong smelling food - eggs are porous and absorb smells Store away from raw meat you may get cross contamination from the meat Wash your hands before and after handling eggs Never use dirty, cracked, broken or washed eggs Do not re-use left-over egg dishes. Raw eggs may contain salmonella. How do you keep the yolk of a hard boiled egg yellow? If you boil the egg and then leave it, the heat changes the iron and sulphur in the egg into iron sulphide which forms the black ring around the yolk. If you cool the egg quickly the black ring does not form. 23
Eggs This diagram shows the cross section of an egg with the different parts. air sac germinal disc yolk egg white, albumin chalaza An egg consists of 11% shell, 58% white 31% yolk. At the round end, the shell and egg membranes separate to form the air sac There are two fine membranes inside the shell which act as a barrier, protecting the egg contents. The germinal disc is the nucleus from which a chick would develop if the egg had been fertilised. The chalaza hold the yolk in place. Egg yolk is more concentrated than egg white and is made of 17% protein, 31 % fat, and vitamins and minerals. The colour of the yolk makes no difference to the nutritional value the colour depends on the food that the chicken eats. Storing eggs Eggs should always be stored in a cool place as heat speeds up physical and chemical changes. A fridge is best for storing eggs. Store eggs with the pointed end downwards so that the rounded end, with its air sac, is uppermost. The albumin is made up of 9.7% protein, 0.5% carbohydrate, 0.5% mineral elements and 87.7% water. 24
Eggs To do Complete the labelling of this egg. Questions 1. Which is the more nutritious - the yolk or the white? Give reasons for your answer. (2 marks) 2. How should eggs be stored? (2 marks) 25
Eggs in food manufacturing Egg products are used as ingredients by bakers, food manufacturers and caterers. Egg products are sold in liquid, frozen or spray dried form. These egg products can save time, may be less expensive, and if pasteurised mean that the products are safer when first used. Whole eggs, which have to be cracked, are used in cake production and egg whites are used for meringues and light sponges for their foaming property. Liquid egg Many bakeries use liquid egg which is convenient and mixes well. The liquid egg is placed in containers and then pumped towards the mixing point. The shelf life liquid egg is 6 days at 0-4 C. Extended shelf life liquid egg products are made by pasteurising at higher temperatures for a shorter time and then aseptically packing the product. For bakeries, products are sold with a 30 day shelf life. How is liquid egg made? Shell eggs are cracked by machines at speeds from 21,000-65,000 eggs per hour. The quality of the of the eggs are carefully monitored to avoid unclean and damaged eggs. Frozen egg is used by the smaller bakeries. Defrosting can spoil the egg, so this product is not popular. Spray dried egg products are added to bakery mixes such as cake mixes. Spray drying Whole egg and yolk are spray dried. Liquid egg albumen is not pasteurised before drying because egg proteins are sensitive to heat. Once dried the albumen powder is pasteurized. Eggs in Catering About 20% of UK eggs are sold to the catering industry. Eggs are economical and easily prepared. Catering outlets include hotels, restaurants, pubs, cafes, fast food outlets, educational establishments, industrial canteens and hospitals. Chilled, pasteurized liquid egg products are very popular in catering. Value added eggs include boiled eggs, scotch eggs, omelettes and cooked scrambled egg. The eggs are either separated into whites and yolks or left as liquid whole egg. The egg is pumped through filters to extract shell particles and chalaza. They are cooled to less than 4 C which stops bacterial growth. The egg is then pasteurized at 64.4 C for a minimum of 2.5 minutes. This time/ temperature destroys all pathogens. The egg is cooled to below 4 C before packing or spray drying. 26
Eggs in food manufacturing This chart shows the use of frozen, liquid and dried egg for food products which are made on a large scale. This chart comes from The Egg File 2006. use of egg products whole egg frozen liquid dried yolk white whole egg yolk white whole egg Cakes x x x x x x x x x Dairy Products x x x x x x Frozen Desserts x x x x x x Biscuits x x x x x x x x x Drinks x x x x x x Baby Food x x x x x Soup x x x Salad Dressing x x x x Noodles x x x x x x yolk white Questions... Name three ways that eggs are made into products. (3 marks) Name 3 advantages of using egg products for a large scale food producer. (3 marks) Explain how a) liquid egg, b) spray dried egg are made. (4 marks) 4. Give 3 examples of value added eggs. (3 marks) 5. What is meant by the term value added? (1 mark) 6. Use the chart above to answer the questions: a) which 2 products can be made from frozen, liquid and dried egg? b) which products are made mainly from egg yolks? c) which products don t use dried egg as one of their ingredients? d) which products don t use egg whites? (8 marks) 27
Properties and functions of eggs - setting and holding air Lemon Meringue Pie Oven 190 C, Gas mark 5 Ingredients Pastry 175 g plain flour 20 g caster sugar 100 g butter or margarine egg yolk and enough water to mix Filling 2 lemons zest and juice Water 25g cornflour 25 g butter 75g caster sugar 2 egg yolks Meringue 2 egg whites 100 g caster sugar Method Rub the butter into the flour and add enough water to make a firm dough. Line a 20 cm diameter flan tin with pastry, fill with paper and baking beans and bake blind for 15 minutes. Remove beans and paper. Mix lemon juice with enough water to make 300ml. Blend in the cornflour, pour in a saucepan with zest, butter and sugar and stir until thick. Remove from heat and stir in egg yolks. Spoon into pastry case. Whisk egg whites until stiff and add the sugar carefully. Spoon over the filling and bake in the oven at 160 C, Gas mark 3. Serve hot or cold. In the recipe for lemon meringue pie, eggs are used in the pastry, the filling and the meringue. What are the functions of egg in the recipe? Pastry - the yolk adds colour and flavour. The yolk enriches and helps to bind the dry ingredients together. Lemon filling - the egg yolks are added to the sauce and they thicken the liquid because the protein coagulates when added to the hot sauce. The egg yolk adds colour and flavour and enriches. The meringue - the egg whites are whisked and the albumen in the egg white protein stretches to hold air bubbles and make a foam. A foam is formed when gas is mixed in liquid - air is held in liquid egg white. The stabiliser in egg white foam is the protein albumen. When baked, the albumen coagulates to form a solid mesh. The main characteristics, properties and functions of eggs are coagulation, foam formation and emulsification. egg white in meringue holds air and makes a foam. egg yolk in the filling thickens the liquid and enriches the sauce. egg yolks in pastry enrich and add colour and bind ingredients together. functions of eggs in lemon meringue pie. 28
Properties and functions of eggs - Colloids Mayonnaise Ingredients 2 egg yolks Salt and pepper ½ tsp mustard 300 ml oil 1-2 tbs white wine vinegar Method Put the egg yolks in a bowl, add seasoning and beat. Gradually add the oil as the mixture thickens. When most of the oil is added, whisk in the vinegar. Store in the refrigerator for a limited time. In the recipe for mayonnaise, eggs are used to make an emulsion. An emulsion is made from two liquids which don t mix - oil and vinegar. They are called immiscible. When shaken together, the oil and vinegar mix together, but if left to stand the two parts separate. To stop the liquids from separating, an emulsifying agent is added. The egg yolk is the emulsifying agent. It contains lecithin. It attracts the oil and the vinegar and holds them together. The mayonnaise makes a stable emulsion which does not separate. To emulsify and stabilise, eggs should be at room temperature. egg yolk contains lecithin which is an emulsifying agent. mayonnaise egg yolks hold the oil and vinegar together in an emulsion which disperses the oil in vinegar. A colloid is a mixture of two parts which are mixed or dispersed into one another. There are 4 types of colloidal structure. 1. Emulsion liquid dispersed in liquid - mayonnaise. 2. Foam - gas in liquid - meringues. Solid foam - gas in solid - baked meringue. 3. Gel - liquid in solid - jam and jellies. 4. Suspension - solid in liquid - white sauce. Questions 1. What is a colloid? 2. What is an emulsion? 3. These are the ingredients for mayonnaise: Ready made mayonnaise Vegetable Oil (77%), Water, Pasteurised Egg & Egg Yolk (8%), Spirit Vinegar, Salt, Sugar,Lemon Juice, Mustard,Flavouring, Antioxidant (Calcium Disodium EDTA), Paprika Extract. Give a reason why the egg is pasteurised in this product. 4. What is the function of egg in the mayonnaise? 29
Properties and functions of eggs - setting and aerating Choux pastry to make choux buns Oven 220ºC Gas mark 7 Ingredients 150 ml water 50 g butter 65 g plain flour 2 eggs Method Heat the butter and water in a saucepan until the butter melts. Beat in the flour and stir over the heat until the mixture forms a ball. Cool the mixture. Whisk the eggs and beat into the flour mixture to make a sticky mixture. Spoon rounds of mixture onto a baking tray and bake for 30-35 minutes until well risen and firm to touch. Cool and then split in half and add the filling of choice. Choux pastry can be used to make eclairs, choux buns, profiteroles and cheese puffs. The eggs are used to bind the ingredients together. help form the structure when the mixture cooks and sets - the eggs coagulate. aerate the mixture as the water in the eggs and in the mixture evaporates and pushes up the pastry to give a light, crisp, hollow case. Sponge cake Oven 200 C, Gas mark 6 Ingredients 100 g butter or margarine 100 g caster sugar 2 eggs 100 g Self raising flour Method Beat together the butter and sugar until smooth. Beat the eggs and beat into the mixture. Stir in the flour until the mixture is smooth. Spoon into cake tins and bake for 20-30 minutes until golden brown and well risen. Cool and store in a dry place. Creamed sponge cake is an emulsion - air is beaten into the fat and sugar to form a air in fat foam. The egg mixes through the mixture to form a water in oil emulsion. When the eggs are beaten into the cake mixture they hold air, and then coagulate on cooking to make a risen cake. sponge cake Eggs have important properties needed for cake making:- aerating, coagulation, binding, enriching, emulsification. The egg helps produce a cake that is well risen, set, light, a good colour, flavour and texture. 30
Properties and functions of eggs - setting ito a semi solid. Quiche Oven 200 C, Gas mark 6 Ingredients Pastry 175 g plain flour 100 g butter or margarine Water to mix Filling 100 g bacon cut into pieces 100 g grated cheese 3 eggs 150 ml milk pepper Method Rub the butter into the flour and add enough water to make a firm dough. Line a 20 cm diameter flan tin with pastry, fill with paper and baking beans and bake blind for 15 minutes. Remove beans and paper. Turn down the oven to 160 C, Gas mark 3. Fry the bacon until crisp. Place the bacon and cheese in the flan case. Beat the eggs and milk and season. Strain over the bacon and cheese. Bake for 35 40 minutes until the filling is set. Serve hot or cold. In a quiche, the egg is used to set the liquid. The egg coagulates with heat and becomes semi-solid. If the egg mixture is over cooked, the egg protein denatures and the protein shrinks and squeezes out the liquid. This can happen if the quiche or custard is cooked for too long at a high temperature. CHEESE AND ONION QUICHE Dietary Information More Questions 1. Name 1 property/function of eggs which are used for each of these egg dishes. a) choux pastry b) cakes c) quiche. Contains milk, egg, mustard & wheat gluten Ingredients Cheese And Onion Egg Custard Filling (70%); Shortcrust Pastry.Cheese And Onion Egg Custard Filling contains: Cows Milk, Whole Egg, Single Cream*, Onion (13%), Medium Fat Soft Cheese (9%)*, Medium Mature Cheddar Cheese* (6%), Red Cheddar Cheese* (5%) (with Colour: Annatto), Rice Starch, Cornflour, Dijon Mustard (Water, Black Mustard Seed, Spirit Vinegar, Salt), Salt, Potato Starch, Wheat Flour, White Pepper. Shortcrust Pastry contains: Wheat Flour, Rapeseed Oil, Palm Oil, Maize Flour, Unsalted Butter*, Cornflour, Salt.* From Cows Milk. Questions Look at the label for Cheese and onion quiche. 1. What allergens are shown on this label? 2. What ingredients are used in the pastry? 3. What ingredients are used in the filling? 4. How could you improve a) the colour of this quiche? b) the amount of vegetables in the recipe? c) the fat content? 5. Draw and label the quiche to show what it looks like. 31
Functional properties of nutrients When made into food products food performs different functions. These are the properties of protein, fat and carbohydrate. The nutrients Protein Fat Carbohydrate What are they? Protein is made of chains of amino acids. Fats are made of fatty acids and glycerol. Carbohydrates include starch and sugars. Extra facts Functional properties Changes when heated Examples of functions Protein structure changes with heat, acids and alkalis and mechanical action such as beating. Proteins have different properties in foods. In meat and fish the proteins denature and coagulate with heat and the food is tastier to eat. Protein in eggs has many uses in cooking such as holding air. The flour protein, gluten, forms bread structure. Proteins denature with heat and the coils of protein unfold. They form a solid network and coagulate and harden. Eggs are beaten to make meringues and coagulate when cooked. Fats can be saturated or unsaturated. Fats in cooking can be in liquid or solid form. Liquid fats are called oils. Solid fats include butter and margarine. Fat is a shortening agent and makes products crumbly and moist. Solid fats trap air to form a foam which helps cakes to rise. Fats enrich by adding flavour and colour. Fats increase shelf life as they keep products moist. Some fats add colour. Fats melt and mix with other ingredients. For frying, fats reach a high temperature. Margarine and sugar hold air when beaten together. Butter adds colour and flavour to cakes. 3 groups of carbohydrate include monosaccharides, disaccharides and polysaccharides. Starch granules in water swell with heat and thicken. This process is called gelatinisation. Starch is used to thicken soups and sauces and give texture and volume to baked goods. Starch turns brown with dry heat. Sugar adds sweetness, improves flavour and helps aerate food and make foams. Sugar is a preservative. Starches brown and change colour such as golden toast and bread crusts. In liquid, they thicken sauces and soups. Flour is used thicken milk to make a sauce. 32
Functional properties of nutrients Colloids are formed when one substance is dispersed in another. Types of colloid How is it formed? Examples A gel Emulsions Foams When a liquid is held in a solid network. When oily and watery liquids mix together. When bubbles of gas are trapped in a liquid. Jam or jelly Oil and vinegar to make a dressing. Mayonnaise. Whisked egg white for meringues or whipped cream. Emulsifying agents are used to stop an emulsion separating. If a gel is allowed to stand for a time it may start to weep. This loss of liquid is known as syneresis. Key facts for eggs in cooking Egg proteins coagulate and set with heat. If the egg protein has held air as in meringues, this sets and holds the structure. Egg proteins stretch when they are beaten to form meringues. Eggs can emulsify oil and water to make mayonnaise and hold the immiscible liquids together. Immiscible means they cannot be mixed. This emulsion is formed when a liquid such as olive oil is dispersed in a liquid such as vinegar. In meringues, the colloidal structure is a foam when gas in the form of air bubbles is dispersed in liquid egg white. When this is baked, it becomes a solid foam. Questions Complete the sentences: 1. Protein is made of chains of (2 marks) 2. Fats are made of and (2 marks) 3. Carbohydrates include and (2 marks) 4. Name 2 things that make protein structure change during food preparation. (2 marks) 5. Name 2 ways that protein changes when heated. (2 marks) 6. Name 2 functional properties of fat. (2 marks) 7. Name 2 functional properties of carbohydrate. (2 marks) 8. Explain what is meant by these terms and give an example in each case. a) gel, b) emulsion, c) foam. (6 marks) 33
Food hygiene Many people suffer every year from eating or drinking unsafe food. Food poisoning is usually caused by poor food handling and inadequate personal hygiene. You need to know the causes of food poisoning to help you set up control systems to prepare safe food products. Food poisoning is most often caused by: storing food in warm conditions undercooking food not reheating food adequately infected food handlers cross-contamination. Rules for food workers Food workers need training in food hygiene. Hands can carry bacteria so always wash hands before you handle any food, after visiting the toilet, after coughing or sneezing and after handling rubbish. Clothing - wear clean, protective clothes for food work. Sickness - if you have sickness or diarrhoea do not work with food until you are better. Cover cuts with a waterproof, blue dressing. Controls are needed in food production to: protect food from contamination by bacteria, poisons and foreign bodies prevent bacteria from multiplying destroy harmful bacteria by cooking or processing. High risk foods Harmful bacteria can grown on high risk foods. High risk foods are often used without further cooking and include foods such as cooked meats. These foods are usually proteins and need to be kept in the refrigerator, away from raw foods. Examples of high risk foods include: cooked meat and poultry, and their products; milk, cream and other dairy products; cooked eggs and their products such as mayonnaise; shellfish and seafood, and cooked rice. Bacteria Facts about food poisoning bacteria help to develop good practice in food handling. Bacteria are microscopic organisms which are found everywhere. Many are harmless but some (pathogens) cause illness. Bacteria need four things to grow or produce toxins (poisons). These are warmth, food, moisture and time. Control these conditions and the bacteria will not multiply so quickly. Temperature control Bacteria like to grow in warm conditions, between 20 C-50 C. To control their growth, food should be kept out of the danger zone of 5 C to 63 C. Most bacteria do not grow in the deep freezer which is kept at temperatures below -18 C. only grow slowly in the refrigerator at 5 C and below grow very rapidly at body temperature 37 C are killed when heated above 63 C. Buying food Check food before you buy it - do not purchase damaged or out-of-date food. Carry perishable food in a cool bag to keep it cool. Store in the refrigerator as soon as possible. Look at the use by or best before dates on food products. Use within these dates and store according to the instructions. Throw away out-of-date food. Storage Store food in clean conditions and at the appropriate temperature. Freezer storage should be at -18 C, refrigerator storage at 5 C or below. If food is stored at ambient temperature (room temperature), make sure it is covered and the store cupboard is well ventilated. Check the fridges regularly with a thermometer to see if they operate below 5 C. Do not put hot food in the refrigerator. Store raw and cooked food separately in the refrigerator and cover food. 34
Food hygiene Cooking food Cook food until it reaches 72 C for at least two minutes in all areas especially in the centre. Food must be reheated to piping hot. It must reach at least 72 C for a minimum of two minutes. If using a microwave cooker, allow for standing time when the temperature evens out, and follow manufacturer s instructions. Keep food warm at temperatures of 63 C and above. If food is not used within the day, throw it away. Cooling food Cool food as quickly as possible as bacteria can grow during the cooling period. Small pieces of food cool more quickly than larger ones. Cut cooked chicken into smaller pieces to help it cool, spread out cooked rice on shallow trays and put it in a cool place where air can circulate. You could place the container in iced water. Cool within a maximum of one hour then cover and put in the refrigerator. Avoid cross-contamination Keep food covered, wear clean protective clothing, use clean towels and cloths. Avoid wiping your face and hair then touching food. Keep equipment such as knives, boards and utensils used for raw and cooked food separate and clean after use. Questions.... 5.. Name 3 main causes of food poisoning. Name 3 high risk foods. What 3 conditions do bacteria need to grow? Give 2 rules each for safe cooking, reheating and keeping food warm. How can you cool food quickly? How can you avoid cross-contamination of food ingredients? 35
Quality Foods People want safe food to eat that is of a good quality. Quality of design Quality of design is about creating a design that is easy to understand and make, with a clear specification and production process. Quality of manufacture is the way the product is made and how effective the quality checks are at each stage. Food needs to be checked during making and cooking to make sure it meets the quality standards by setting up a system for quality assurance. Quality Assurance systems identify in advance where problems are likely to occur during food production. They are set up before manufacturing begins. The Quality Assurance system is used throughout the production of a food product. Ingredients must be of good quality and the suppliers must be reliable The recipe details must be followed this is the recipe specification The manufacturing process must make safe food which is properly cooked. The food must be packed and labeled accurately. The product has to be stored at the correct temperature in a safe environment. The product has to be distributed safely to food stores. Quality checks These are some quality checks that should be in place during food production. Quality of ingredients making sure they are fresh, attractive, nutritious. Working to designated tolerances which means you have to make things to a size, thickness and weight. Checking on texture, colour and uniformity Measuring weight of ingredients and the weight of the final cooked product. Checking the sizes, shapes, thickness and quantity that is made. Temperature checks including cooking, cooling and storage temperatures and these have tolerance limits. So the storage temperatures for cold food is within a range of 0-5ºC. Detectors are used to find metal and foreign bodies such as glass. The food has microbiological checks to see if it is safe to eat. Control systems are then set up to stop these problems happening. Quality controls (QC)are the routine checks made throughout the production process. QCs are used to check and test a product as it is made. If people use only quality control, the faults in a product are only identified after the product has been made. They need the quality assurance system to support the controls. 36
Quality Foods Total Quality Management TQM includes quality assurance but also total monitoring of the production systems. Companies can gain an ISO9000 certificate when they reach very high standards. It is important for food companies to make sure they produce good quality products. Test by Quality control How often Standard Maximum Minimum Raw materials in Each delivery Must meet specification Chicken in Each delivery Temperature 5ºC 0ºC Ingredients checks Cooking temperature Chiller temperature 2 hours Must meet recipe specification Each batch or component Greater than 75 ºC 75 ºC 2 hours Less than 5ºC 4ºC -1ºC Metal detector ½ hourly 2.5mm non Fe, 2mm Fe Component weight Organoleptic tests Each product Daily To the specification To the attribute sheet Food that is made on a large scale must be the right size and shape. The size has tolerance levels - that is the amount of difference that is allowed for the food to be completed and labelled. Despatch temperatures Each pallet Less than 5ºC 4ºC 0ºC This chart shows the quality control tests for a cooked chicken dish in a food factory. The raw materials are checked and must meet control checks. You can see the cooking and chilling temperature. The product has organoleptic tests which means it is tasted. The final despatch temperature is controlled. Questions.... What is the delivery temperature for the chicken? How often are the ingredients checked? What is the cooking, chilling and despatch temperature for the chicken? How is the product checked for pieces of metal? 37
Quality Controls and Checks This chart shows the process for making a quiche and how you put Quality controls in place. Process What could go wrong? Quality control and checks Heat the oven Oven is too low a temperature Check oven has reached temperature. Mix the pastry ingredients flour, fat, salt. Then add water. Line the flan tins and bake blind. Mix the filling egg, milk, seasoning and flavours. Pour filling into flan and bake. If ingredients are not mixed properly, pastry is not right consistency. Pastry must fit in tin with no holes. Mix evenly and make sure no egg shell is in mixture. Don t over or underfill the flan case. Check that mixture is right texture. Reject any with holes. Check mixture by looking. Check mixture by looking. Bake 20-25 mins Do not underbake or over bake. Set timer to check cooking time. See if filling is firm. If not, bake more. Cool For safety, chill quickly. Test with food probe that they are cool. This chart shows the critical controls - they must be made or you throw away the product. Check dry ingredients Check eggs Check milk Pour filling into flan case. Bake Critical controls Make sure the ingredients are free from foreign bodies and within date of use. Eggs must be within use by date. Do not let them cross contaminate other ingredients, so discard shells and wash hands after use. Check if within date of use. Make sure filling does not cross contaminate other products Make sure quiches are thoroughly baked. If not what Throw away old or dirty ingredients Old eggs must be thrown away. Raw egg is dangerous, so keep working area clean. Throw away if undercooked. Questions 1. In the quiche making, what do you think are the 2 most important quality checks? 2. Critical controls are essential or the product will not be safe to eat - which 2 controls do you think are the most important and why? 3. Temperature control is an important in food production. Give 3 examples in the process of making the quiche that need temperature control points. 38
Quality Controls and Checks To do Complete the Quality control charts for the products below. Use the recipes in the book to help with the processes. scotch eggs meringues chocolate eclairs sweet and savoury tarts. Roll out pastry to an even thickness Process What could go wrong? Quality control and checks Process What could go wrong? Quality control and checks 39
Food production systems A food production system has three parts. Input- starts up the system - the different ingredients, materials and machinery needed to start the system. Process the way the system changes - things that happen to ingredients to change it into output. Output the end result- the finished food product. The food production system for cakes is shown as Sponge cake Input Process Output Ingredients -eggs, sugar, flour. Beating, baking cakes To do Complete the input, process and output for the following products: meringue made from egg whites and sugar pancakes made from egg, flour and milk and fried in oil or butter mayonnaise made from egg yolks, oil and seasoning and whisked to make smooth. Complete these charts for each product. Meringue Input Process Output Ingredients -eggs, sugar. This table shows you checks that are taken during the food production process. Production Process Production Storage Preparation Cooking Transport Temperature in storage What has to be checked Raw materials must be safe and of high quality. High-risk foods should be stored below 5 C. Equipment and food handlers must follow hygiene regulations. Food must be cooked thoroughly to prevent food poisoning. Temperature control may be necessary for high-risk foods. Food must be kept below 5 C during storage and distribution. Examples of checks Looking at things - checking fruits and vegetables Computer checks - thermometers monitor oven temperatures and time Food and equipment has microbiological checks for safety. Many of these checks can be monitored by computer and require very little intervention from food production workers. Continuous monitoring gives feedback on all stages of production and action can be taken quickly to sort any problems. Early detection of problems can prevent waste of ingredients and reduce the need to shut down the whole production line, which would cost money and take time. Pancakes Input Process Output Ingredients -eggs, flour, milk. Mayonnaise Input Process Output Ingredients -eggs, oil, seasoning. Care must be taken at all stages of a food s development - from production through to consumption - to ensure that it is safe and of high quality. What is the process for making pancakes? 40